Posted: Mon Aug 29, 2005 10:25 am Post subject: Darwinism Verses Intelligent Design
Currently in America there is a growing debate about whether to teach Darwinism as a theory that explains the evolution of life based on random mutation and natural selection – that is the survival of the fittest on the on the one hand and the concept of Intelligent Design which states that life is too complicated for Darwinism to work on the other. The following three articles that appeared in yesterday’s Calgary Herald cover all the issues involved in the debate.
Design or Darwin?: The push to teach Intelligent Design as faith-based science in America's schools has reignited the long-standing debate between creationists and evolutionists over how life began
Sunday, August 28, 2005
It's not often that scientific theory becomes political controversy, but when that happens, it can become nasty.
The United States is now convulsed over the teaching of Darwinism in its schools. Conservative Christians, committed to some notion of divine creation, object to what they see as dogmatic secular propaganda that the universe, life and human life are the result of random chance. The educational establishment, represented by the National Centre for Science Education, resist what they consider the intrusion of dogmatic religion into science.
Yet the curriculum battle is just a symptom of the controversy in evolutionary research itself, a controversy that transcends national borders. In biology and microbiology departments worldwide, there are signs of a "paradigm shift" -- the latent but suppressed awareness that the Darwinian mechanisms, random mutation and natural selection, may not be able to explain the elegance and complexity of life.
In early August, the U.S. Office of Special Counsel, a federal investigator, confirmed what biologist Richard Sternberg already knew: because he'd dared to allow publication of an article arguing for Intelligent Design theory, his scientific colleagues set out to destroy his career.
Sternberg, with two PhDs in evolutionary biology, was a prominent Smithsonian Institution researcher, editing the peer-reviewed Proceedings of the Biological Society of Washington. Though not an Intelligent Design proponent himself, in 2004, he allowed publication of an article critical of Darwinism and advocating Intelligent Design. He wanted to "stir the scientific pot," he said, since "science only moves forward on controversy."
The article, Intelligent Design: The Origin of Biological Information and the Higher Taxonomical Categories, was written by Cambridge PhD Steve Meyer, now director of the Centre for Science and Culture at the Seattle-based Discovery Institute. Prior to publication, following strict scientific protocol, Meyer's article had been approved by a confidential panel of biologists. But Sternberg still sinned by allowing it to see the light of day.
Senior Smithsonian scientists spread lies about him as "a shoddy scientist and a closet Bible thumper," the OSC documented. His (non-existent) religious and political affiliations were investigated. He was denied workspace and virtually driven from the building. Though all allegations have been proven false, no retractions have ever been issued.
The scandal came at a bad time for mainstream evolutionary biology. There is growing public anger over what is seen as heavy-handed dogmatism, like University of Minnesota biologist P.Z. Myer's call for "public firing and humiliation" of teachers who question Darwin.
In the conservative "red states," boards of education are opting to "teach the controversy" between natural evolution and biblical creationism -- which means mainly teaching the problems besetting Darwinian theory. George W. Bush himself has publicly supported that movement.
Internationally, Pope Benedict XVI has corrected a misapprehension about his predecessor's position. In the late-1990s, Pope John Paul II had referred to evolution as a "fact." But in July, papal spokesman Cardinal Christoph Schonborn said that, while the Catholic Church can accept the idea of a common origin and descent for all life, it could never accept the idea of "an unguided, unplanned process of random variation and natural selection."
"Any system of thought that denies or seeks to explain away the overwhelming evidence for design in biology is ideology, not science," Schonborn said.
So Darwinism is besieged, and now there's a contender in the wings.
As early as 1982, as microbiologists learned more about the complexity of the cell, scientist Charles Thaxton raised "the design hypothesis" in his book, The Mystery of Life's Origins. This was followed by Michael Denton's purely skeptical critique of Darwinism, Evolution: A Theory in Crisis. Then in 1987, California lawyer Philip Johnson's book, Darwin On Trial, gave a popular and persuasive synthesis of both.
Major academic conferences followed in 1992 and 1996 -- the latter at Biola University drawing more than 500 participants.
That same year, 1996, the Discovery Institute's Centre for Science and Culture was founded in Seattle, with Meyer as its director.
Since then, the centre's 40 yearly research fellows -- working scientists such as Michael Behe, William Dembski, Jay Richards and Jonathan Wells -- have produced 54 books on Intelligent Design, published by the likes of the Cambridge University Press. And fully 417 PhD scientists have signed on to the Centre's Statement of Dissent from the Darwinian orthodoxy.
There is an irony in the Intelligent Design controversy. ID theorists tend to be pariahs almost as much among traditional Creationists, as they are by doctrinaire Darwinians.
Mainstream evolutionists lump ID theorists in with biblical "Young Earthers," who reject the geological and fossil evidence as deceptive. Journalists over-simplify the debate with "God versus Darwin" headlines. And Time magazine's cover story, Aug. 15, 2005, brands Intelligent Design as a "Subtler Assault" on science, while dismissing ID arguments as "scientifically abstruse, jargon-heavy."
In fact, Intelligent Design theorists generally accept all the geological and biological evidence. They argue that the evidence itself falsifies any purely materialistic interpretation. Random chance alone cannot explain the amazing complexity of life.
Bucking biblical literalists, ID theorists generally accept the universe is 14 billion years old and began in the "Big Bang." They accept that the Earth is 4.5 billion years old, that single-cell life -- bacteria, plankton and algae -- began 3.8 billion years ago, and while they speak of Intelligent Design, they don't mention a "Designer."
All that puts them in the bad books of biblical Creationists, such as the Institute for Creation Research's Henry Morris and Dwayne Gish.
But Darwinism's problems begin with the evidence, IDers argue. Darwinism's skeletons first started tumbling out of its closet with the 1986 book Evolution: A Theory in Crisis, by biologist Michael Denton, who yet dismissed both creationism and ID as "occult." But Darwinian problems there are.
First, in a materialistic account, there is still nothing close to an explanation for the emergence of the first life: complex, interlocking, reproducing structures of molecules that buck the Second Law of Thermodynamics dictum, everything tends to randomness.
"We're appreciating that the life of a simple cell is far more elegant and far more sophisticated than we ever expected," says Lehigh University biologist Michael Behe, author of the book Darwin's Black Box. "We're continually discovering new machines inside the cell, the molecular equivalent of little dump trucks and factories."
Even at their simplest, Behe argues, cells have "irreducible complexity." His favourite example is the bacterial flagellum, the little motor that propels a one-celled organism. The complex parts must work in unison: the little molecular motor running on a stream of mild acid, a molecular frame holding it to the cell wall, a whip-like propeller. No random development of the individual parts could be of the slightest use to the organism, until all the parts can work together. Yet, Darwinism requires that each part develop randomly and be preserved, until such point as they can work together.
The famous 1953 Miller-Urey experiment, where an electric spark energized a beaker of "primordial soup," produced a few simple organic molecules, but nothing close to the design of a living cell, Behe said. So, faced with "irreducible complexities" in organisms, he says, it's less far-fetched to suppose a design is somehow built-in.
Second, geologists have now documented the "Cambrian Explosion."
Darwin supposed organisms have random mutations, then natural selection lets beneficial mutations survive and harmful ones die. So, given a very long time of very gradual change, simple cells could develop into complex organisms. But Darwin himself warned that abrupt emergence of new species would call his theory into question, and that's what happened.
The first single-celled animals appeared 3.8 billion years ago, and for the next 3.3 billion years, any evolution stayed on the level of single cells. Then, precisely 543 million years ago, every category of complex life on Earth emerged in an unbelievably short five to 10 million years: the Cambrian Explosion.
Does God have a place in class?
Intelligent Design ignites great debate
John Angus Campbell and Bill Marty
For the Calgary Herald
August 28, 2005
Evolution is once again in the public spotlight. As always, local school boards and legislatures debate it; lawyers from California to Kansas, Georgia and Pennsylvania litigate it. But this time around there is a noticeable change.
The topic is no longer fuelled merely by the next lawsuit or flap over textbook stickers. One opens a recent New Yorker and sees that even in that bastion of highbrow liberalism, culturally as far from Kansas, Georgia, Alabama or Tennessee as one can get, the topic is featured in The Talk of the Town. "Intelligent Design" was a segment on Night Line, has become grist for cartoonists, a staple for talk-show hosts and fair game for the jibes of Jon Stewart.
And it is not even fake news. The president of the United States announces support for teaching evolution along with critiques of it posed by ID theorists.
Bill Frist, Senate majority leader and Republican presidential hopeful, having distanced himself from the president on stem-cell research, heads for the centre (and the polls show 70 per cent of the population would support him) by endorsing the president's position on teaching evolution.
Time magazine runs a cover story, Evolution Wars, depicting Michelangelo's famous Sistine Chapel painting of God stretching his finger to a reclining Adam. In place of Adam, Time substitutes a bust-like shot of a chimp, its eyes pensively staring at the subtitle positioned directly before its face: "The push to teach 'intelligent design' raises a question: Does God have a place in science class?"
Friday's Washington Post breaks a story about Rick Sternberg, a research scientist associated with the Smithsonian who, as editor of a science journal, published a peer-reviewed article by Steven Meyer questioning Darwinian orthodoxy.
The Post reported that an official investigation had vindicated Sternberg's formal complaint that his decision to publish the article had been punished by a campaign of intimidation and harassment by officials at the Smithsonian.
Not so long ago, the Sternberg story might have rated at least a short peak of discussion. Not any more. It was instantly pushed from public view not by an event, but by the cultural momentum of the topic itself.
Sunday's New York Times carried a front-page story on the ID controversy that spilled over to fill (replete with pictures and captions) five full columns in the front section. As we write, both Monday and Tuesday's New York Times feature front page stories in a series exploring points of difference between scientists on opposing sides of the issue.
Since it is not necessarily the headlines, but deeper changes in common language that indicate the direction of our thinking, William Safire's regular feature On Language in Sunday's New York Times magazine was particularly revealing.
Safire examined the derivations of the terms "Intelligent Design" and its catchy pejorative "neo-Creo" (for neo-creationism) coined by Philip Kitcher. But Safire gave "the last word on this old controversy" to Leon Cooper, Nobel laureate and neuroscientist, who observed: "If we could all lighten up a bit perhaps, we could have some fun in the classroom discussing the evidence and the proposed explanations -- just as we do at scientific conferences."
Whatever one thinks about Intelligent Design or Evolution, there is no dispute that understanding these terms is now a matter of merest cultural literacy.
Should this discussion be part of the science curriculum? As a practical matter, to ignore the issue places the science teacher in an untenable position. At this late date, to ask the science teacher to repeat all the usual disclaimers -- to insist that there is no criticism of evolutionary theory worth talking about -- brings to mind the scene from the Wizard of Oz in that awkward moment just after Dorothy's dog Toto has tugged open the screen to reveal the "wizard" pulling the levers of the machine that produces the official version of Truth.
Is Intelligent Design smoke and mirrors? Or is it not, rather, a part of the historic and philosophic matrix from which our current theories emerged, giving it at least one clearly legitimate place in the science curriculum? And, speaking of scientific literacy, is it really possible to read the Origin of Species with its 105 rebuttals of ID interpretations of natural phenomena (first edition) without bothering to understand that which Darwin is arguing against?
The distinguished Canadian Darwinist and philosopher of science Michael Ruse in his latest book, The Evolution-Creation Struggle, (Harvard, 2005) does not offer simple solutions to the many questions raised by what he calls this "Quarrel . . . within the family," but refreshingly urges both philosophic Darwinists and those skeptical of Darwin to search for common ground for the sake of cultural progress.
Though we as authors of this essay differ between ourselves about Darwin's theory, in the spirit of Prof. Ruse's volume and following the example of his recent Cambridge University Press (2004) collaboration with the ID theorist William Dembski, Debating Design, we urge participants in the discussion to resist demonizing their opponents and to consider a simple principle central to liberal education and central equally to the role of science in the open society we all cherish.
We propose that teachers should present Darwin's theory of evolution as Charles Darwin himself did: as a credible, but contestable scientific argument. Even though teachers should make unambiguously clear that Darwin's is the established theory, rather than teaching Darwin's theory as incontrovertible "truth," teachers should present the main arguments for Darwinism and encourage students to evaluate them critically -- as they would any other theory, whether new or long established.
There are good reasons for teaching not just Darwin's theory, but all of science this way.
First, teaching science as argument helps students understand the nature of science. Contrary to the stereotype of scientists as tight-lipped technicians in white coats wordlessly producing facts from boiling beakers, scientists typically deliberate -- and argue -- about how best to interpret experimental evidence.
Second, teaching science as argument helps prepare tomorrow's citizens to use scientific information to decide personal and public issues -- of personal health, of when to ask for a second medical opinion, of how to make sense of public health-care policy, environmental policy, stem-cell research, advances in technology, and of how to make informed decisions about government funding of scientific research.
Third, though science is not and should not be democratic, teaching science as a forum for open argument -- even about the nature of science -- fosters cultural trust in science as an antidote to ideology and as an enterprise essential to democracy.
Darwin, to his great credit, included in the Origin of Species every objection to his theory he could think of.
When evolution is taught as Darwin himself presented it -- as a theory resting on a large and diverse body of facts, but one from which thoughtful people (and even scientists) can nevertheless dissent -- fewer parents will object to their children learning about it.
The opening sentence of the final chapter of Darwin's Origin can provide a guide to school board members and educators as they shape science education policy and curriculum: "This whole volume is one long argument . . . "
John Angus Campbell and Bill Marty are Fellows at Discovery Institute, Seattle, Wash. John Angus Campbell is editor with Stephen C. Meyer of Darwinism, Design and Public Education (Michigan State University Press, 2003).
Creationism taken to task
Intelligent Design idea troubles U of C professor
For the Calgary Herald
August 28, 2005
Few issues are as capable of arousing strong opinions and heated discussion as the origin and evolution of life. This isn't surprising. Origin stories are prominent in every culture and religion and they contribute to our conception of ourselves.
The topic of evolution arouses strong feelings in people because in this area the findings of science are most obviously in conflict with deeply held tenets of their origin concept. In contrast, the theory of electromagnetism or the atomic theory don't elicit that kind of response because most cultural origin stories and religious doctrines are fairly mute on the nature of electricity or the composition of matter.
The Intelligent Design movement is just one of many examples of backlash against modern science. It is an interesting and particularly troubling one, in that it seeks to borrow the respectability of science through choice of language and superficially scientific sounding arguments while at the same time attacking the core of scientific reasoning.
So much has been written and said in debates on creationism versus evolution that it would be hopeless to try to summarize and resolve the entire debate in this short piece. However, I will make two simple and related points which I think get at the heart of the issue.
The first is that evolution and Intelligent Design are not two theories that can be compared and evaluated using scientific rationale. The second is that science and religion represent completely different ways of understanding the world, and that they are fundamentally concerned with different questions. Conflict is created only when people insist on using one to make sense of things that only exist in the other.
One of the more common charges laid by creationists against evolution is that it is "just a theory." In the scientific sense of the word, this is correct. However, there is an important distinction to make here.
The word "theory" has a somewhat different meaning in science than in everyday use. Evolutionary theory is a theory in the scientific sense, but that does not mean it is unlikely to be correct or that there is real controversy in the scientific community about the theory that life has evolved through natural processes.
In fact, all areas of science are built on theories, including those that are used to build airplanes, develop drugs or design computer chips.
Interestingly, we do not hear proponents of Intelligent Design clamouring for physics instructors to warn students that the existence of atoms and molecules is "just a theory," although this would be equally appropriate as warning students about evolutionary theory in biology class.
Theories are fundamental to science and this relates to the central difference between evolutionary theory and creationist concepts such as Intelligent Design. It may seem counterintuitive, but science proceeds by suggesting propositions about the material world, called hypotheses, and then trying to disprove them.
This is because the only thing we can ever say with absolute certainty is that something isn't true. We can never be sure that a hypothesis is true because there is always the possibility that something that we haven't yet thought of might explain whatever it is that the hypothesis is supposed to explain.
A theory is a hypothesis or group of related hypotheses that can explain a large number of observations. The theory of evolution is such a theory. One of the most important criteria of a scientific theory is that it must be at least potentially falsifiable. That is, you must be able to set up a critical test so that if the theory fails the test it can be said to be false.
This is why the Intelligent Design concept is not a theory and therefore not an idea that can be assessed with the tools of science. Proponents of Intelligent Design assume from the outset that life is created directly by God and that it is too complex and intricate to have been shaped by materialistic forces such as natural selection.
That is, they already know the "truth" because it has been handed to them by religion. We can't construct a critical test for this idea because every inconsistency can be explained away by divine intervention.
In everyday use, the word theory can mean an idea which is in doubt or even just a hunch. Evolution is clearly not a theory in this sense because the hypothesis that life evolves has stood up to intense scientific scrutiny for about a century and a half.
The vast majority of modern biologists would agree with the eminent evolutionary biologist, Theodosius Dobzhansky, when he wrote, "Nothing in biology makes sense except in the light of evolution." The probability that some observation will ever be made that will disprove the theory of evolution is minuscule. This is the most we can ever say about any well-accepted scientific theory.
However, science remains logically open to the possibility that it will. Proponents of Intelligent Design often accuse evolutionary biologists of failing to look for alternative explanations for their observations. This is a profound irony because the Intelligent Design idea represents an unwillingness to consider alternative explanations for life other than those that people have held for thousands of years.
In contrast, science is premised on the assumption that we don't know the truth and that ultimately -- even sometimes reluctantly -- we must embrace new ideas when old ones are found to be false. The theory of evolution should be taught in biology classes because it is the theory which best explains the diversity of life. Intelligent Design has no place in biology precisely because it isn't a theory at all.
My second point is that the debate between evolution and creationism represents a conflict between different ways of understanding the world and not one between competing explanations for the same phenomenon.
Science deals with questions about the material world around us including its origin and history. Our ability to use science to manipulate in chemistry, physics, medicine etc., is one measure of the success of the scientific method as a way to understand the material world.
In contrast, religions are generally not concerned with explaining the material world. The Bible, for instance, does not codify second century Western thought on the nature of air or gravity. Instead, religious thought centres on metaphysics, ethics, and spirituality.
We would not look to science for answers about the meaning of life. Similarly, Watson and Crick did not use religion to investigate the molecular composition of DNA. It makes no more sense to use religious beliefs to determine the evolutionary origins of bacteria, horses, or humans.
Pope John Paul II recognized this fundamental difference between the domains of discourse of science and religion in his Message to the Pontifical Academy of Sciences in 1996 in which he reiterated the Vatican's position that there is no fundamental conflict between evolution and Catholic doctrine.
Charles Darwin, who was a religious man, would doubtless have agreed. As an evolutionary biologist and educator, one thing that I'm conscious of when interacting with students is to not use scientific arguments to undermine or influence my students' religious beliefs.
I wish that proponents of Intelligent Design were equally willing to avoid imposing their religious beliefs on my discipline and classroom.
Benedikt Hallgrimsson is associate professor and associate dean in the faculty of medicine at the University of Calgary.
In a finding that is likely to intensify the debate over what to teach students about the origins of life, a poll released yesterday found that nearly two-thirds of Americans say that creationism should be taught alongside evolution in public schools.
The poll found that 42 percent of respondents held strict creationist views, agreeing that "living things have existed in their present form since the beginning of time."
In contrast, 48 percent said they believed that humans had evolved over time. But of those, 18 percent said that evolution was "guided by a supreme being," and 26 percent said that evolution occurred through natural selection. In all, 64 percent said they were open to the idea of teaching creationism in addition to evolution, while 38 percent favored replacing evolution with creationism.
The poll was conducted July 7-17 by the Pew Forum on Religion and Public Life and the Pew Research Center for the People and the Press. The questions about evolution were asked of 2,000 people. The margin of error was 2.5 percentage points.
John C. Green, a senior fellow at the Pew Forum, said he was surprised to see that teaching both evolution and creationism was favored not only by conservative Christians, but also by majorities of secular respondents, liberal Democrats and those who accept the theory of natural selection. Mr. Green called it a reflection of "American pragmatism."
"It's like they're saying, 'Some people see it this way, some see it that way, so just teach it all and let the kids figure it out.' It seems like a nice compromise, but it infuriates both the creationists and the scientists," said Mr. Green, who is also a professor at the University of Akron in Ohio.
Eugenie C. Scott, the director of the National Center for Science Education and a prominent defender of evolution, said the findings were not surprising because "Americans react very positively to the fairness or equal time kind of argument."
"In fact, it's the strongest thing that creationists have got going for them because their science is dismal," Ms. Scott said. "But they do have American culture on their side."
This year, the National Center for Science Education has tracked 70 new controversies over evolution in 26 states, some in school districts, others in the state legislatures.
President Bush joined the debate on Aug. 2, telling reporters that both evolution and the theory of intelligent design should be taught in schools "so people can understand what the debate is about."
Senator Bill Frist of Tennessee, the Republican leader, took the same position a few weeks later.
Intelligent design, a descendant of creationism, is the belief that life is so intricate that only a supreme being could have designed it.
The poll showed 41 percent of respondents wanted parents to have the primary say over how evolution is taught, compared with 28 percent who said teachers and scientists should decide and 21 percent who said school boards should. Asked whether they believed creationism should be taught instead of evolution, 38 percent were in favor, and 49 percent were opposed.
More of those who believe in creationism said they were "very certain" of their views (63 percent), compared with those who believe in evolution (32 percent).
The poll also asked about religion and politics, government financing of religious charities, and gay men and lesbians in the military. Most of these questions were asked of a smaller pool of 1,000 respondents, and the margin of error was 2.5 percentage points, Pew researchers said.
The public's impression of the Democratic Party has changed in the last year, the survey found. Only 29 percent of respondents said they viewed Democrats as being "friendly toward religion," down from 40 percent in August of 2004. Meanwhile, 55 percent said the Republican Party was friendly toward religion.
Luis E. Lugo, the director of the Pew Forum on Religion and Public Life, said: "I think this is a continuation of the Republican Party's very successful use of the values issue in the 2004 election, and the Democrats not being able up until now to answer that successfully. Some of the more visible leaders, such as Howard Dean and others, have reinforced that image of a secular party. Of course, if you look at the Democratic Party, there's a large religious constituency there."
Survey respondents agreed in nearly equal numbers that nonreligious liberals had "too much control" over the Democratic Party (44 percent), and that religious conservatives had too much control over the Republican Party (45 percent).
On religion-based charities, two-thirds of respondents favored allowing churches and houses of worship to apply for government financing to provide social services. But support for such financing declined from 75 percent in early 2001, when Mr. Bush rolled out his religion-based initiative.
On gay men and lesbians in the military, 58 percent of those polled said they should be allowed to serve openly, a modest increase from 1994, when 52 percent agreed. Strong opposition has fallen in that time, to 15 percent from 26 percent in 1994.
An article yesterday about a poll on Americans' views on the teaching of creationism misstated the margin of error of findings taken from a smaller sample of respondents who were asked about religion and politics, government financing of religious charities and gays in the military. It was 3.5 percentage points, not 2.5.
Humans, chimps share 96% of their DNA
Genome project offers clues about evolution
For CanWest News Service
September 1, 2005
CREDIT: Yerkes National Primate Research Center, Associated Press
Scientists used DNA from Clint the chimpanzee in a huge project comparing the genes of humans and chimps.
Successful sequencing of the chimpanzee genome and comparison with the human genome has offered scientists an unparalleled "peek into evolution's lab notebooks."
The discovery that humans and chimps share from 96 to 99 per cent of their DNA sequences will help researchers better understand our own biology and could lead to medical breakthroughs.
"The goal isn't just butterfly collecting or to simply describe mammals," said Eric Lander, one of the 67 scientists involved in the project who shared authorship of the paper on the chimp-human genome comparison published Wednesday in the journal Nature.
"All of that comparative work across mammals is about informing the human genome for medicine. Until we understand all the working parts within our genome, we won't really be able to practise the most informed medicine."
Dixie Magar, a senior scientist at the B.C. Cancer Agency, called the publication "the paper we've been waiting for."
Magar is studying the difference in DNA sequences of humans, chimpanzees and Rhesus monkeys. Understanding such differences may provide insight into the genetic basis of some human diseases.
"What a lot of us are interested in is what makes us human, what genetic characteristics are different between humans and chimpanzees," Magar said. "There are obviously critical genetic differences which distinguish the two species and a lot of people are interested in finding out what those are."
Francis Collins, the director of the National Human Genome Research Institute, called the chimp genome sequencing a historic achievement.
"This ability to draw evolutionary comparisons really adds great richness to what would otherwise be a one-dimensional story.
"Now we can look at it through the lens of evolution and peek into evolution's notebooks to see what really went on there."
The Chimp Sequencing and Analysis Consortium researchers noted the typical human protein has accumulated just one unique change since chimps and humans diverged from a common ancestor some six million years ago.
Researchers said the number of genetic differences between a human and a chimp is about 10 times greater than between any two humans.
Despite the similarities between the two genomes, researchers point out some 35 million DNA differences between the two species. In the next few years, the scientists hope to determine what DNA sequence changes in humans may have led to such human-specific features as walking upright, a greatly enlarged brain and complex language skills.
Among the scientists' findings is the discovery that more than 50 genes present in the human genome are missing or partially deleted from the chimp genome. The corresponding number of gene deletions in humans is not yet precisely known.
But already researchers have uncovered implications of their findings. For instance, humans have lost the function of one gene that produces an enzyme that may help protect other animals against Alzheimer's disease.
"Knowing that there is a human-specific difference in this pathway is very important when we study Alzheimer's disease models in other animals," said Tarjei Mikkelsen, one of the study's lead authors.
Eleven parents in the US state of Pennsylvania are taking their local
school board to court in an attempt to protect the teaching of evolution.
The Dover Area School Board requires teachers to say evolution is a
just a theory and is still being tested.
Teachers have to announce that Intelligent Design is an alternative
explanation for the origin of life.
The parents and scientists argue that ID is a form of religious
belief, which has no place in the science curriculum.
'Not a theory'
At one level, the argument is about a very tiny part of the US school
curriculum. But at another, it is about the very meaning of science.
For well over 100 years, biology has accepted Charles Darwin's idea of
evolution through variability and natural selection - survival of the
fittest as it is better known.
The underlying mechanisms of evolution are totally natural - there is
no role for a higher being.
And every new breakthrough - even the tremendous discovery of the
genetic code - has fitted easily into the Darwinian framework.
So when the school board in Pennsylvania chose to instruct its
teachers to say that Darwin's theory is "not a fact", and that there
are "gaps in the theory", mainstream scientists became extremely prickly.
The head of the American Association for the Advancement of Science
says that the alternative put forward by the board, Intelligent
Design, "is not even a theory".
And as for the gaps in evolution, Dr Alan Leshner says: "today's great
mystery is tomorrow's great discovery".
Intelligent Design, which argues that key moments in the history of
life were guided by a higher power, is being promoted in schools
across 20 states in the US.
It argues the case that evolution cannot explain key features of the
biological form, such as the human eye. ID proponents say this organ
is so complex, it could only have arisen as a result of some guiding hand.
The case of the Dover School board is seen as vital by scientific
organisations in restricting its spread.
They say that this is the biggest case in 18 years - taking the fight
back to a court decision that "creation science" - ID's precursor -
was in fact religion and therefore unconstitutional in the secular US
They hope to prove the same of intelligent design, and they are
prepared to take it all the way to the Supreme Court, if they have to.
HARRISBURG, Pa., Sept. 26 -- New barrages sounded in the evolution war Monday
as lawyers for a group of parents challenged the teaching of "intelligent
design" as nothing more than an old argument for God's hand wrapped in fancy new
"This clever tactical repackaging of creationism does not merit consideration,"
Witold Walczak, legal director of the Pennsylvania American Civil Liberties
Union and a lawyer for the parents, told U.S. District Judge John E. Jones in
opening arguments. "Intelligent design admits that it is not science unless
science is redefined to include the supernatural."
This is, he added, "a 21st-century version of creationism."
Eleven parents from Dover, in central Pennsylvania, are seeking to block their
school board from requiring that high school biology teachers read a
four-paragraph statement to students that casts doubt on Darwin's theory of
evolution. This mandatory statement notes that intelligent design offers an
alternative theory for the origin and evolution of life -- namely, that life in
all of its complexity could not have arisen without the help of an intelligent
The foremost advocates of intelligent design are silent on whether that
intelligent hand belongs to God or some other intelligent force, even including
a space alien. The school board, represented by the Thomas More Law Center, a
conservative, religiously grounded nonprofit firm, took the position that the
case was about freedom of speech.
"There is in fact a controversy over Darwin's theory," Richard Thompson, chief
counsel for the law center, said afterward during an impromptu news conference
on the courthouse steps. "Clearly both theories have religious implications. But
this is not about God."
Last year, however, Dover school board members -- who voted 6 to 3 for the new
policy -- made it clear that they believed that the origin of life was guided by
a heavenly hand. Several of them suggested that their views on evolution are far
closer to Young Earth Creationism, which holds that God created the world 6,000
years ago and that Noah's flood covered Earth, than to intelligent design.
One board member told a public meeting -- in a remark he has since tried to
deny -- that the nation "was founded on Christianity, and our students should be
taught as such."
The war over the teaching of evolution is almost a century old, the first great
shot having been fired in Dayton, Tenn., in the famous 1925 Scopes "monkey
trial," in which the ACLU defended a teacher convicted of teaching evolution.
Former presidential candidate and prairie populist Williams Jennings Bryan
represented the school board. Another shot sounded in 1987, when the Supreme
Court prohibited the teaching of creationism in public schools, ruling that it
was not science but religion and violated the separation of church and state.
Shortly after that Supreme Court ruling, intelligent design began to appear on
the lecture circuit, championed by a small band of scientists and academics.
Intelligent design advocates tend to concentrate their criticism on Darwinian
theory; they have been far less successful at laying a foundation for a new
scientific theory, which by definition must be testable.
This was a point hammered at Monday as the ACLU called its first witness,
Kenneth R. Miller, a Brown University biology professor and author of a biology
textbook used in nearly half the schools in the nation -- including in Dover.
Miller noted that virtually every prominent scientific organization in the
United States has upheld Darwin's theory of evolution as an unshakable pillar of
Intelligent design, he emphasized, has not fared nearly as well.
"Intelligent design is inherently religious. It is a form of creationism,"
Miller said during four hours of testimony that often resembled an extended
college seminar. "If you invoke a spiritual force in science, I can't test or
"Scientific theories are not hunches," he added. "When we say 'theory,' we mean
a strong, overarching explanation that ties together many facts and enables us
to make testable predictions."
The school board's attorneys countered by arguing that several of the leading
intelligent design theorists are respected scientists and professors. And they
said the school board merely makes students aware of another viewpoint. The
board also mandated the placement in the school library of the book "Of Pandas
and People." The book makes the case for intelligent design, and the school
board's attorneys made the case that it was sort of an alternative textbook.
But Miller rejoined in his testimony that it was nothing of the sort. He
pointed out many examples of outdated or distorted science in the book. He said
the errors were so numerous as to amount to an intentional misreading of
science, designed to drive unwary students to reject evolutionary theory.
"The errors in the book are systematic," Miller said.
Both sides plan to call a long line of witnesses, from scientists to
philosophers to local teachers and parents. And, in a rare moment of agreement,
they said the case is likely to eventually reach the Supreme Court.
Fossils challenge old evoluton theory
Washington, Aug 10: Surprising research based on two African fossils suggests our family tree is more like a wayward bush with stubby branches, challenging what had been common thinking on how early humans evolved.
The discovery by Meave Leakey, a member of a famous family of paleontologists, shows that two species of early human ancestors lived at the same time in Kenya. That pokes holes in the chief theory of man's early evolution — that one of those species evolved from the other.
And it further discredits that iconic illustration of human evolution that begins with a knuckle-dragging ape and ends with a briefcase-carrying man.
The old theory is that the first and oldest species in our family tree, Homo habilis, evolved into Homo erectus, which then became human, Homo sapiens. But Leakey's find suggests those two earlier species lived side-by-side about 1.5 million years ago in parts of Kenya for at least half a million years. She and her research colleagues report the discovery in a paper published in Thursday's journal Nature.
The paper is based on fossilized bones found in 2000. The complete skull of Homo erectus was found within walking distance of an upper jaw of Homo habilis, and both dated from the same general time period. That makes it unlikely that Homo erectus evolved from Homo habilis, researchers said.
It's the equivalent of finding that your grandmother and great-grandmother were sisters rather than mother-daughter, said study co-author Fred Spoor, a professor of evolutionary anatomy at the University College in London.
The two species lived near each other, but probably didn't interact, each having its own "ecological niche," Spoor said. Homo habilis was likely more vegetarian while Homo erectus ate some meat, he said. Like chimps and apes, "they'd just avoid each other, they don't feel comfortable in each other's company," he said.
There remains some still-undiscovered common ancestor that probably lived 2 million to 3 million years ago, a time that has not left much fossil record, Spoor said.
Overall what it paints for human evolution is a "chaotic kind of looking evolutionary tree rather than this heroic march that you see with the cartoons of an early ancestor evolving into some intermediate and eventually unto us," Spoor said in a phone interview from a field office of the Koobi Fora Research Project in northern Kenya. That old evolutionary cartoon, while popular with the general public, is just too simple and keeps getting revised, said Bill Kimbel, who praised the latest findings. He is science director of the Institute of Human Origins at Arizona State University and wasn't part of the Leakey team.
"The more we know, the more complex the story gets," he said. Scientists used to think Homo sapiens evolved from Neanderthals, he said. But now we know that both species lived during the same time period and that we did not come from Neanderthals.
Now a similar discovery applies further back in time.
Susan Anton, a New York University anthropologist and co-author of the Leakey work, said she expects anti-evolution proponents to seize on the new research, but said it would be a mistake to try to use the new work to show flaws in evolution theory.
"This is not questioning the idea at all of evolution; it is refining some of the specific points," Anton said. "This is a great example of what science does and religion doesn't do. It's a continous self-testing process."
For the past few years there has been growing doubt and debate about whether Homo habilis evolved into Homo erectus. One of the major proponents of the more linear, or ladder-like evolution that this evidence weakens, called Leakey's findings important, but he wasn't ready to concede defeat.
Dr. Bernard Wood, a surgeon-turned-professor of human origins at George Washington University, said in an e-mail Wednesday that "this is only a skirmish in the protracted 'war' between the people who like a bushy interpretation and those who like a more ladder-like interpretation of early human evolution."
Leakey's team spent seven years analyzing the fossils before announcing it was time to redraw the family tree — and rethink other ideas about human evolutionary history. That's especially true of most immediate ancestor, Homo erectus.
Because the Homo erectus skull Leakey recovered was much smaller than others, scientists had to first prove that it was erectus and not another species nor a genetic freak. The jaw, probably from an 18- or 19-year-old female, was adult and showed no signs of malformation or genetic mutations, Spoor said. The scientists also know it isn't Homo habilis from several distinct features on the jaw.
That caused researchers to re-examine the 30 other erectus skulls they have and the dozens of partial fossils. They realized that the females of that species are much smaller than the males — something different from modern man, but similar to other animals, said Anton. Scientists hadn't looked carefully enough before to see that there was a distinct difference in males and females
Posted: Sun Aug 19, 2007 3:56 pm Post subject: Re: www.harunyahya.com
A whole website is devoted to darwin's theory in many of its ramifications from an Islamic point of view. www.harunyahya.com is based on the works of a turkish scholar. his central idea comes from the original publications of darwin himself.
THE ABSENCE OF INTERMEDIATE SPECIES.
If the darwin's theory is correct about mutations and natural selection, we will see a continuum of mutations (in the sense of closely spaced discrete steps of changes) and each intermediate specie would have millions or billions of fossils that would then mutate in different directions before the best one is selected. Also there would be some species with a maxima that need not come down. for example, there would be a fish-bird with evolutionary advantage over both fish and bird so that it can escape predators in water and land and find food in both environments. We do not see such a creature.
HYahya then connects his theory of evolution with political theories of fascism, communism, nazism and zionism to show how it gave the justification to these
political ideologies to carry out their heinous crimes based on the assumption
that humans are mere animals in constant conflict for survival. Dialectical materialism was fused with evolution in these movement to justify crimes against humanity.
I dont see why star munir and kmaherali bring long articles from amateur sources like newspapers and ignore authentic and comprehensive websites?
Most beginners have a raw mind and they should start on a subject with the most concise and most authentic sources. HYahya has a few basic ideas only (on darwinism) which he has elaborated into many hundred free ebooks, presentations and videos. The site is very good. I first found it in connection with trying to understand the human hormone system on which the site has an excellent ebook. Be sure to watch the video on love among animals on the website, its a most enjoyable one.
Ya Ali Madad
Mowla Ali Madad,
How can you saythat the information by Harun Yahya is authentic source and articles posted by me and Karim are not so. IThe article I had posted was from Zee News report.
I had read once some of H yaha on reincarnation and I not agreed much with him.
Posted: Mon Aug 20, 2007 6:46 pm Post subject: Re: www.harunyahya.com
While I did the service of making a single post after a relatively comprehensive study, and posting a gist and giving a reference to his site, you and kmeherali copy articles.
Ya Ali Madad
The intention of this thread was to post articles written by qualified people in the field (and not as amateurs as you seem to suggest), was to bring to the attention of the readers the debate around the issue and the wider implications in terms of the curriculum. I did however express my personal opinion in another thread as under:
And We created you, then fashioned you, then told the angels: Fall ye prostrate before Adam! And they fell prostrate, all save Iblis, who was not of those who make prostration.(007:011)
So, when I have made him and have breathed into him of My Spirit, do ye fall down, prostrating yourselves unto him.(015:029)
So the angels fell prostrate, all of them together(015:03)
And He taught Adam all the names, then showed them to the angels, saying: Inform Me of the names of these, if ye are truthful (002:031)
In my opinion based upon the above verses of the Glorious Quran, Adam is not the first man but symbolic of the first process or occurence of the self consciousness and intellect in the highest form of evolved creation. The dust or clay is symbolic of the fact that we share genes with the rest of creation. The fashioning is symbolic of the evolutionary process of life. The breathing of my spirit alludes to the infusion of intellect which enables man to be self conscious on the one hand and able to comprehend creation and the Creator on the other- 'and he taught Adam all names'.
This implies that the psychological state of Adam would have been quite mature in order to be able to accomodate the new consciousness and intellect and with it to take charge of his life.
In his much acclaimed book, The Language of God, Francis Collins one of the scientists at the forefront of the science of genetics, quotes the explanation of C.S. Lewis a distinguished scholar of myth and history on Adam and Eve as per the following excerpt from the book and which echoes the above interpretation of the creation of Adam.
Many believers find the story of Adam and Eve compelling as literal history, but no less an intellect than C. S. Lewis, a distinguished scholar of myth and of history, found in the story of Adam and Eve something resembling a moral lesson rather than a scientific textbook or a biography. Here is Lewis's version of the events in question:
For long centuries, God perfected the animal form which was to become the vehicle of humanity and the image of Himself. He gave it hands whose thumb could be applied to each of the fingers, and jaws and teeth and throat capable of articulation, and a brain sufficiently complex to execute all of the material motions whereby rational thought is incarnated. The creature may have existed in this state for ages before it became man: it may even have been clever enough to make things which a modern archaeologist would accept as proof of its humanity. But it was only an animal because all its physical and psychical processes were directed to purely material and natural ends. Then, in the fullness of time, God caused to descend upon this organism, both on its psychology and physiology, a new kind of consciousness which could say "I" and "me," which could look upon itself as an object, which knew God, which could make judgments of truth, beauty and goodness, and which was so far above time that it could perceive time flowing past. ... We do not know how many of these creatures God made, nor how long they continued in the Paradisal state. But sooner or later they fell. Someone or something whispered that they could become as gods. . . . They wanted some corner in the universe of which they could say to God, "This is our business, not yours." But there is no such corner. They wanted to be nouns, but they were, and eternally must be, mere adjectives. We have no idea in what particular act, or series of acts, the self-contradictory, impossible wish found expression. For all I can see, it might have concerned the literal eating of a fruit, but the question is of no consequence.
Posted: Tue Aug 21, 2007 3:41 am Post subject: Re: www.harunyahya.com
A whole website is devoted to darwin's theory in many of its ramifications from an Islamic point of view. www.harunyahya.com is based on the works of a turkish scholar. his central idea comes from the original publications of darwin himself.
THE ABSENCE OF INTERMEDIATE SPECIES.
Ya Ali Madad
Mowla Ali Madad,
How can you saythat the information by Harun Yahya is authentic source and articles posted by me and Karim are not so. IThe article I had posted was from Zee News report.
I had read once some of H yaha on reincarnation and I not agreed much with him.
I can say it because his reasoning is sound. I can independently analyze it based on my knowledge and corroborate outside the field of science also to the Holy Quran and the story of Adam and Eve. While I did the service of making a single post after a relatively comprehensive study, and posting a gist and giving a reference to his site, you and kmeherali copy articles. The universal method in all examinations and also for teaching is to give a lecture or write a small essay based on your own study and in your OWN WORDS so that you can defend it and then give references for greater detail and substantiation to initiate other students/readers on the path. Otherwise, just copying an article in examination would be considered acceptable and the teacher who reads verbatim from the book would be the most interesting one. If you try to write in your own words, your faculty of critical analysis would be heightened and you would produce a better tutorial. Why dont you do some through research and write an article in your own words and giving references to a site where your favorite theory is as thoroughly discussed as HYahya has done to refute evolution.
The subject here is evolution and not reincarnation. Stick to the topic or the thread would degenerate. We all know no human is perfect in everything.
P.S. If you are a scientist, you would be aware of persistance of fallacious theories for long periods of time. These are ultimately refuted when people re search the truth and dont accept facts based on someone's reputation. Here is an example: Big bang or the oscillating universe? Both theories have existed for a long time. The former is now in favor based on scientific evidence. The latter was in fashion at an institute many years ago where I was and there was a preponderance of atheistic jews from the US and Israel in the department. Yet now the Big bang is the one leading today based on the scientific evidence. I never accepted oscillating universe despite lack of hard evidence for either. Because you have to then go to other disciplines, namely religion.
I have not went out of the topic and have started discussion on reincarnation as you mentioned. I have just given example and my view point that while I had read about reincarnation I have find that he has written just from one perspective and while comparing other religion he just tried to prove the view point of Quran in any way.May be that is what creating attraction in the article.
Anyways I dont have any problem with him or his website. What I meant to say you cant say that just this website has authentic information on this topic. I will say thanks for sharing it as we are here just to share knowledge and get more knowledge.
As far as posting of articles is concrned. What do you think...if we all start posting just website links here then how would it look? Would not it look like all are here just advertising here. Whats wrong in posting articles here? It is not against the rule of forums. Any one who will refer the forum can get experts opinion and current articles, news etc.
Scaredy-fish or bon vivant? Personalities found in trout
CanWest News Service
Monday, November 26, 2007
Fish have personalities. Ordinary Canadian brook trout exhibit different traits: some social, others not. Some risk-takers, others scaredy-fish. And so on.
University of Guelph scientists noticed the different personalities as they sat by the Credit River, west of Toronto, watching trout feed. Then they scooped out the fish and ran them through six days of personality tests in the lab, and even some swimming tests.
And the revelation suggests an answer to an old question: how can different species, with different types of behaviour, evolve from a single starting point?
The idea of personalities is starting to spread across our views of the whole animal kingdom, says Rob McLaughlin, the Guelph biologist who ran the study. This seems obvious in the case of dogs or chimpanzees, but less obvious among fish.
"We've known that out in the field, these young brook trout exhibit differences in their foraging behaviour -- what they're feeding on," he said.
In many lakes and rivers, there are two visibly different subgroups of the same fish species -- a slower and fatter version near shore and a sleeker, faster one out in open water.
But the Credit River brookies haven't reached that stage. They all looked the same, all living in a pool together, yet showing behaviour that differed. Some slower trout stayed near shore and hunted for tiny crustaceans while others rushed around in deeper water, picking insects off the surface.
Off the fish went to the Guelph aquarium for tests.
McLaughlin and student Alex Wilson found that the personalities stayed distinct even after the young fish, still just two to four centimetres long, left their natural homes.
For instance, he put the fish in a dark tube in the aquarium. The more active fish were always the ones that emerged into the main body of the tank first. They were more ready to take risks, and less afraid of unfamiliar objects in the water.
"What they do in the field predicts what they do in the lab," he said. "We were getting this sense that they perceive the environment differently, and the kind of things we measured are part of what people are starting to call personality traits in animals."
Darwin`s `Group Selection` theory no longer a taboo
Washington, Nov 29: Charles Darwin's theory of group selection, which has been neglected for about four decades, has once again found supporters in leading evolutionary scientists David Sloan Wilson and Edward O. Wilson.
The theory, published in Darwin's 'The Descent of Man' in 1871, proposes an evolutionary explanation for morality and pro-social behaviours.
Darwin proposed the theory with the words: "Although a high standard of morality gives but a slight or no advantage to each individual man and his children over the other men of the same tribe...an advancement in the standard of morality will certainly give an immense advantage to one tribe over another."
Almost a century after its publication, the theory became taboo and has not recovered since.
David Wilson and Edward Wilson, whose book 'Sociobiology: The New Synthesis' brought widespread attention to the field in 1975, have now called for an end to forty years of confusion and divergent theories in their landmark article.
In a landmark article for The Quarterly Review of Biology, 'Rethinking the Theoretical Foundation of Sociobiology', they propose a new consensus and theoretical foundation that affirms Darwin's original conjecture, and is supported by the latest biological findings.
The two evolutionary scientists trace much of the confusion in the field to the 1960's, when most evolutionists rejected "for the good of the group" thinking, and insisted that all adaptations must be explained in terms of individual self-interest.
In an even more reductionistic move, genes were called "the fundamental unit of selection", as if this was an argument against group selection.
With the publication of 'The Selfish Gene' by Richard Dawkins in 1976, scientific dogma entrenched in popular culture.
While evidence in favour of group selection began accumulating almost immediately after its rejection, its taboo status prevented a systematic re-evaluation of the field to this day.
Writing about the current theory and evidence, Wilson and Wilson said that natural selection was unequivocally a multilevel process, as Darwin originally envisioned, and that adaptations could evolve at all levels of the biological hierarchy, from genes to ecosystems.
They concluded: "Selfishness beats altruism within groups. Altruistic groups beat selfish groups. Everything else is commentary."
Chimps performed about as well as college students at mental addition, U.S. researchers said Monday in a finding that suggests non-verbal math skills are not unique to humans.
The research from Duke University follows the finding by Japanese researchers earlier this month that young chimpanzees performed better than human adults at a memory game.
Prior studies have found non-human primates can match numbers of objects, compare numbers and choose the larger number of two sets of objects.
"This is the first study that looked at whether or not they could make explicit decisions that were based on mathematical types of calculations," said Jessica Cantlon, a cognitive neuroscience researcher at Duke, whose work appeared in the Public Library of Science journal PLoS Biology (www.plosbiology.org).
"It shows when you take language away from a human, they end up looking just like monkeys in terms of their performance," Cantlon said in a telephone interview.
Her study pitted the ape math team of Boxer and Feinstein -- two female chimps named for U.S. senators Barbara Boxer and Dianne Feinstein of California -- with 14 Duke University students.
"We had them do math on the fly," Cantlon said.
The task was to mentally add two sets of dots that were briefly flashed on a computer screen. The teams were asked to pick the correct answer from two choices on a different screen.
The humans were not allowed to count or verbalize as they worked, and they were told to answer as quickly as possible. Both chimps and humans typically answered within 1 second.
And both groups fared about the same.
Cantlon said the study was not designed to show up Duke University students. "I think of this more as using non-human primates as a tool for discovering where the sophisticated human mind comes from," she said.
The researchers said the findings shed light on the shared mathematical abilities in humans and non-human primates and shows the importance of language -- which allows for counting and more advanced calculations -- in the evolution of math in humans.
"I don't think language is the only thing that differentiates humans from non-human primates, but in terms of math tasks, it is probably the big one," she said.
Keep creationism out of science classes: academy
Report backs teaching of evolution
Friday, January 04, 2008
The U.S. National Academy of Sciences Thursday issued a spirited defence of evolution as the bedrock principle of modern biology, arguing that it, not creationism, must be taught in public school science classes.
The academy, which operates under a mandate from Congress to advise the government on science and technology matters, issued the report at a time when the theory of evolution faces renewed attack by some religious conservatives.
Creationism, based on the explanation offered in the Bible, and the related idea of "intelligent design" are not science and, as such, should not be taught in public school science classrooms, according to the report.
"We seem to have continuing challenges to the teaching of evolution in schools. That's something that doesn't seem to go away," Barbara Schaal, an evolutionary biologist at Washington University in St. Louis and vice-president of National Academy of Sciences, said in a telephone interview. "We need a citizenry that's trained in real science."
Evolution is a theory explaining change in living organisms over the eons due to genetic mutations.
The report stated that the idea of evolution can be fully compatible with religious faith. But teaching creationist ideas in science classes confuses students about what constitutes science and what does not, according to the report's authors.
The report was released by the academy and the Institute of Medicine, which advises policymakers on medical issues. It was written by a committee headed by University of California-Irvine biology professor Francisco Ayala.
"Biological evolution is one of the most important ideas of modern science. Evolution is supported by abundant evidence from many different fields of scientific investigation. It underlies the modern biological sciences, including the biomedical sciences, and has applications in many other scientific and engineering disciplines," the report states.
U.S. President George W. Bush said, in 2005, American students should be instructed about "intelligent design" alongside evolution as competing theories. "Part of education is to expose people to different schools of thought," Bush said.
Advocates of "intelligent design" contend that some biological structures are so complex they could not have appeared merely through natural processes.
February 19, 2008
What People Owe Fish: A Lot
By NATALIE ANGIER
Being a resolute hydrophobe who has no more desire to go for a swim than might a kitten in a bag or Luca Brasi in “The Godfather,” I admit I never thought of myself as a large, scaleless fish out of water.
Yet after reading Neil Shubin’s brisk new book, “Your Inner Fish,” and speaking with other researchers who use fish to delve into the history of vertebrates in general and ourselves in particular, I realize that many traits we take pride in, the body parts and behaviors we exalt as hallmarks of our humanity, were really invented by fish.
You like having a big, centralized brain encased in a protective bony skull, with all the sensory organs conveniently attached? Fish invented the head.
You like having pairs of those sense organs, two eyes for binocular vision, two ears to localize sounds and twinned nostrils so you can follow your nose to freshly baked bread or the nape of a lover’s irresistibly immunocompatible neck? Fish were the first to wear their senses in sets.
They premiered the pairing of appendages, too, through fins on either side of the body that would someday flesh out into biceps, triceps, rotating wrists and opposable thumbs.
Or how about that animated mouth of yours, with its hinged and muscular jaws; its enameled, innervated teeth; and a tongue that dares to taste a peach or, if it must, get up and give a speech? Fish founded the whole modern buss we now ride.
The fish’s tale of firsts is a tall one. “The backbone that holds us upright, that’s a fish invention,” Dr. Shubin, a paleontologist at the University of Chicago and the Field Museum, said in an interview. “The cranial nerves that we use to control the muscles in our jaw, that we use to talk and to hear, they relate to a fish’s gill arches. The basic wiring in our skull, the body plan we take for granted, that’s part of our story. It’s all from fish.”
Our inner fish extends beyond physicality. New research reveals that many fish display a wide range of surprisingly sophisticated social behaviors, pursuing interpersonal, interfishal relationships that seem almost embarrassingly familiar.
“Fish have some of the most complex social systems known,” Michael Taborsky, a behavioral ecologist at the University of Bern in Switzerland, said. “You see fish helping each other. You see cooperation and forms of reciprocity.”
Dr. Taborsky and his colleagues have studied the social lives of African cichlids, colorful freshwater fish from Lake Tanganyika. The cichlids live in relatively large groups of 10 or so individuals, a dominant breeding pair and a retinue of adult and adolescent helpers. The helpers share in all duties, Dr. Taborsky said. They defend territory, they help keep the nests tidy and they clean, fan and oxygenate the breeding pair’s eggs. When the eggs hatch into larvae, the helpers take up the babies in their mouths for cleaning — all the while forgoing their own breeding efforts.
Significantly, the helper fish are often unrelated to the royal pair over whose spawn they so officiously fawn. What’s in it for the helpers? “We call it pay to stay,” Dr. Taborsky said. “Helpers are allowed to stay in the territory and gain security and protection against predators. But they have to pay rent, so to speak, or they risk being expelled.”
In laboratory experiments, the researchers have shown that when subordinate cichlids are temporarily prevented from performing their duties, the fish compensate at the first chance by ostentatiously redoubling displays of helpful behaviors.
Researchers have identified many other surprising analogies between humans and fish. Dr. David Reznick of the University of California, Riverside, has discovered that female guppies go through a kind of menopause, surviving well beyond their reproductive life span, a finding that may bear on the evolution of menopause among women.
Catherine L. Peichel of the Fred Hutchinson Cancer Research Center in Seattle has determined that the fish are awfully human, particularly in their migratory prowess.
“Sticklebacks migrated out of their ancestral marine habitat and invaded lots of new environments over an evolutionary time frame of about 10,000 generations,” Dr. Peichel said. “That’s roughly the same number of generations since humans migrated out of Africa and adapted to habitats all over the world. It’s a parallel process.”
Even some of the same genes that shifted format in human migrations, like those responsible for skin pigmentation, also changed as sticklebacks ventured from salt water to fresh.
If everything we can do fish can do wetter, we should not be surprised. “The vertebrate family tree,” Dr. Shubin said, “is really a tree of fish.”
Some 30,000 species of fish are alive, a figure that represents more than half of all known backboned beings and encompasses Ripley’s oddities like fish that fly, fish that climb trees and fish that change from male to female and back again.
Fish are also the oldest group of vertebrates, the earliest possessors of rudimentary teeth, skulls and spinal cords having arisen from wormlike predecessors maybe 550 million years ago. That means that fish have had a long time to experiment with body plans and strategies.
Spurring the evolution of the vertebrate body plan, Dr. Shubin said, was a benefit of being an active predator. The origin of jaws and teeth “was a great equalizer,” he said, adding, “It allowed smaller fish to eat bigger fish.”
The advent of teeth demanded protection against those teeth, and the earliest skulls were little more than thousands of tiny teeth fused together. Through the pairing of sense organs up front, in the well-shielded head, fish gained spectacular new powers to seek food and slink from the seekers.
“The increasingly competitive landscape was a cauldron for the invention of new things,” Dr. Shubin said — including, 365 million years ago, the power to hoist your scaly self out of the sea and begin sampling the plants and arthropods that preceded you on dry ground.
In 2004, Dr. Shubin and his colleagues reported discovering the fossil of one such pioneer, a half-fish, half-amphibian creature they named Tiktaalik. Plucky Tiktaalik had rudimentary shoulders and enough upper body muscle to do push-ups, and so the beefcake era was born.
February 24, 2008
Birds Do It. Bees Do It. Dragons Don’t Need To.
By NEIL SHUBIN
DRAGONS and virgin births are the stuff of myth and religion. Except, that is, in Kansas, where they have recently come together in a way that should alter the way many of us look at nature and demonstrate the risks in our habit of using it to help us make ethical decisions.
Keepers at Wichita’s zoo got a surprise last year when they found developing eggs inside the Komodo dragon compound. Komodos are large rapacious lizards naturally found in Indonesia, but increasingly populating zoos around the world. Finding fertile embryos of dragons is a joyous occasion — there are only a few thousand of the lizards in the wild and captive breeding may be the only way to keep the species around.
But these eggs — two of which hatched a few weeks ago — were unusual: they developed from a female that had had no male of the species in close proximity for more than a decade. Judging from similar occurrences over the past two years in Britain, it appears that these lizards sometimes use a form of virgin birth in which eggs hatch without conception. The embryos are genetic clones of the mother.
Komodos — like many fish, amphibians and reptiles — have lots of reproductive tricks. For example, females can store sperm for a long time, tiding them over when conditions may be poor for reproduction. It’s possible that the Wichita dragon eggs could have been fertilized by the sperm from a male that was on site a long time ago. But DNA analysis of the “miracle embryos” from Britain showed that every bit of their DNA came from the females, and nobody should be surprised if this is also true of the Kansas dragons.
Virgin birth, known to biologists as parthenogenesis (from the Greek, “parthen” meaning virgin or maiden and “genesis,” beginning), has been seen in other species over the years. Some lizards occasionally produce offspring in this way. So do several species of fish, including a female hammerhead shark at the Henry Doorly Zoo in Omaha that produced offspring without a male last year.
The shark example is particularly striking because sharks are very primitive living fish, having shared a common ancestor with us over 400 million years ago. Biological cloning is not a recent invention of scientists; it is an ancient ability. And sharks, fish and lizards are probably only the tip of the iceberg. We know of virgin birth only in those rare instances when we’ve been lucky enough to see it. Nobody knows how common it is because there has been no systematic search for the phenomenon.
The big question these virgin births raise is this: If some females can get along without males, why does any species have males? The reason is simple. With virgin birth, hatchlings are simply genetic duplicates of the mother. In a world of clones, there would not be enough variation for populations to adapt. Virgin birth, then, is a great stopgap measure to ensure the survival of a species, but works against it in the long haul.
Cloning is one of many mechanisms species use to survive in a dangerous world. Indeed, the diversity of reproductive strategies seen in animals staggers the imagination. Some reptiles do not determine sexes genetically, but rely on different incubation temperatures to determine the development of males and females. Other creatures can actually switch sexes during their lifetimes, being born male and developing as females. Still others can switch sexes based on behavioral cues in the social group. There is no one way that creatures start development, grow and form sexes — there are many varied ways.
Unfortunately, humans seem to forget this fact when we find ourselves turning to nature to guide us through difficult choices, such as arguments about whether life begins at conception, or over the proper structure of the family. Or, more recently, regarding the morality of cloning. Whether we’re talking about raising bigger cattle or growing life-saving organs or trying to “live forever,” both sides like to stress their abilities to judge what is “natural.” Judging from Komodo dragons, lizards and sharks, the answer seems to be that for reproduction, almost anything goes.
And that is the point. Biology is about variation. Without variation, the world would be static and unchangeable, and species would gradually disappear as they failed to meet challenges like changing climates and environments. So as we continue our very necessary debates over ethical issues, let’s bear in mind that morality is a concept limited to our species. The natural world is a fuzzy place that doesn’t always accommodate our decidedly human need to find cut-and-dried categories.
Neil Shubin, an associate dean at the University of Chicago and the provost of the Field Museum, is the author of “Your Inner Fish: A Journey Into the 3.5-Billion-Year History of the Human Body.”
April 25, 2008
What Darwin Saw Out Back
By CORNELIA DEAN
IN 1860, while studying primroses in the garden of Down House, his home in Kent, England, Charles Darwin noticed something odd about their blooms.
While all the flowers had both male and female parts — anthers and pistils — in some the anthers were prominent and in others the pistils were longer. So he experimented in his home laboratory and greenhouses, cross-pollinating some plants with their anatomical opposites. The results were striking.
“He determined that if they cross-pollinate, they produce more seed and more vigorous seedlings,” said Margaret Falk, a horticulturalist and associate vice president at the New York Botanical Garden. The variation is evolution’s way of increasing cross-pollination, she said.
Now the Botanical Garden is replicating this work, and more of Darwin’s Down House experiments, in a stunning, multipart exhibition called “Darwin’s Garden: An Evolutionary Adventure.”
In all, the tour is 33 stops, spread throughout about half of the garden’s 250 acres. Visitors who enter the exhibition through the Enid A. Haupt Conservatory will encounter a replica of a room in Darwin’s house, designed so they can look through the window, as he did, to a profusion of plants and bright flowers: hollyhocks, flax and of course primroses, what Todd Forrest, the garden’s vice president for horticulture, calls “a typical British garden.” On a table stands a tray holding quills, brushes, sealing wax and tweezers, the kinds of simple tools Darwin used to conduct his world-shaking research.
Darwin grew the flowers not just for their own sake, Mr. Forrest said, but as subjects for observation and experiment, work he carried out in his home laboratory and greenhouses, on workbenches like those in the exhibition. The work displayed on the benches is typical of studies Darwin made of pollination, how plants grow, even what happens when a carnivorous plant devours an insect. Orchids on display remind visitors of the varieties Darwin studied, and how his observations and dissections of their blooms led him to conclude that particular species were pollinated by particular species of insects, a conclusion later research confirmed.
The exhibition also includes a “tree of life” map that guides visitors to the garden’s plants and describes where they fit in the natural scheme of things; books, drawings and notes, some in Darwin’s own hand; and an interactive exhibit for children.
It anticipates two Darwin anniversaries next year — his 200th birthday and the 150th of his world-changing book, “The Origin of Species.”
Though most people associate that book and Darwin’s ideas generally with his voyage to the Galápagos and his study of finches there, his work with plants was far more central to his thinking, said David Kohn, a Darwin expert and science historian who is a curator of the exhibition.
Even in the Galapágos he focused on plants, said Dr. Kohn, who is general editor of the Darwin Digital Library of Evolution at the American Museum of Natural History. “He did not even label the finches,” he said. “He was fascinated by plants,” particularly the way their variation and sexual reproduction challenged the idea that species were stable, a key idea in botany at the time.
As Dr. Kohn writes in the exhibition catalogue, “plants were the one group of organisms that he studied with most consistency and depth over the course of a long scientific career” of collecting, observing, experimenting and theorizing. But Darwin studied more than flowers. He was intrigued by what Dr. Kohn calls the “behavior” of plants — how they move, respond to light, consume insects and otherwise act in the world.
So another exhibit in the Garden conservatory replicates Darwin’s studies of climbing plants. Mr. Forrest said Darwin studied plants whose roots move along walls, whose stems twine, whose tendrils curl around other plants and which climb as their leaves grow into tendrils. Visitors who stop to ponder this display will also be able to see, in the garden library, the wispy, primitive drawings Darwin made as he studied plant movement and insect eating. Dr. Kohn said the drawings, which remind him of time-lapse photography, are among his favorite items here even though, as he noted, “Darwin was a terrible drawer.”
In his orchard at Down House, Darwin established a “weed garden” by clearing a patch of sod and tracking the germination and growth of every seed that sprouted there. The Botanical Garden has done much the same thing with a small patch in the conservatory.
Most seedlings in Darwin’s weed garden vanished, Ms. Falk said, losses he attributed to slugs. (“That’s a gardener for you,” Mr. Forrest said, “always complaining about something.”)
The work Darwin carried out in his gardens, greenhouses and home laboratory is particularly impressive, Ms. Falk said, given that he was limited to a simple microscope and equipment like “quills, matchsticks, bits of wire.”
“It was really in his own garden that many of his ideas came together,” she added.
As visitors walk through the Botanical Garden they will be able to follow an illustrated maps of the tree of life — the plant part of it, anyway — that tell them where the plants they can see fit in the evolutionary framework.
In the garden’s LuEsther T. Mertz Library, they will encounter what Jane Dorfman, its exhibitions coordinator, calls “treasures”: some on loan from Cambridge University, where Darwin studied, some from Harvard and some the fruit of what Dr. Kohn called “rummaging” in the garden’s extensive collection of Darwiniana. Among them are Darwin’s notes from university botany class, a plant specimen he collected on the Galápagos and his preliminary sketch of the tree of life with his note, “I think,” at the top.
The gallery also displays his “Experiment Book” with notes and drawings of experiments he carried out in his garden, and studies of flowers that led him to predict — accurately — what kind of bird or insect would pollinate them.
Nearby is Darwin’s 1857 letter to Asa Gray, the American botanist who was a major supporter, in which he laid out, one by one, the ideas he would shortly turn into “The Origin of Species.” Among other things, Dr. Kohn said, the letter is notable because it “proves Darwin’s priority” by demonstrating that it was he, and not his fellow naturalist Alfred Russel Wallace, who developed the theory first.
“It shows he’s got it,” Dr. Kohn said.
The tree of life exhibits, comprising an unusual mix of living plants, laboratory expertise and historical documents, show that many plants are surprisingly close relatives of others that seem quite different, a concept that helps botanists when they look for likely sources of useful plant chemicals or worry about maintaining biodiversity.
For example, “squashes and oaks are related,” said Dennis W. Stevenson, the garden’s vice president for laboratory science. “Who’d a thunk it?”
But while many branches move off simply and neatly in ways botanists understand — they are “totally resolved,” Dr. Stevenson said — other evolutionary branchings occur in clumps called polytomies, areas where the family history of plants is still unknown.
One major polytomy involves cycads and conifers. Dr. Stevenson is among researchers working with the support of the National Science Foundation to unravel this evolutionary mystery. So far, he said, researchers have come up with two possible explanations. Although they contradict each other, “I like them both,” Dr. Stevenson said.
Garden officials recognize that there are those who challenge Darwin’s ideas, but for them there is nothing controversial about them. “Our whole science is based on evolution,” Gregory Long, the Botanical Garden’s president, said, as he surveyed the team of horticulturalists installing the flowers that replicate Darwin’s experiments.
“It’s the heart of our science,” he said. “We wouldn’t be here if it hadn’t been for Darwin.”
“Darwin’s Garden: An Evolutionary
Adventure” opens Friday and runs through June 15 at the New York
Botanical Garden, Southern Boulevard and 200th Street, Bedford Park, the Bronx; (718) 817-8700, nybg.org.
Over the coming year, an international panel chosen by The Globe and
Mail will select the 50 Greatest Books ever written. Each week, a
single work will be discussed by an expert or a writer passionate
about the work in question. This is the third in the series.
Coming to the end of his On the Origin of Species, published in
1859, English naturalist Charles Darwin described the book as "one
long argument." This is the way to read this epoch-defining work.
Darwin claimed that all organisms, living and dead, including
ourselves, are the products of a long, slow, gradual process of
change — evolution — from just a few simple forms (perhaps one). He
also claimed that the cause was something he called "natural
selection." More organisms are born than can survive and reproduce;
there is therefore a consequent "struggle for existence," and those
that succeed will have features different from those that fail.
There will be a natural winnowing, with change accumulating through
But how was Darwin to argue for something that, almost by
definition, we cannot see? He used the same methods we find in law
courts. Why, if no one saw it happen, do we convict the butler of
killing his noble employer? Perhaps because the butler was caught
red-handed killing someone else, but more probably because of the
clues: bloodstains, murder weapon, motive, broken alibi. Darwin was
happy to point to the successes of animal and plant breeders in
effecting change — fatter pigs, woollier sheep — but his real
argument was that evolution through natural selection explains the
clues of nature and, conversely, the clues of nature make his
Most of Origin is a trip through the world of life, pointing to its
marvels and its mysteries. Why do we find, as we go down the fossil
record, that the features become more general, possessed by an
increasingly wide spectrum of animals and plants today? Simply
because these older forms are the shared ancestors of many of
today's forms, which have subsequently specialized into different
species. Why do we find that the inhabitants of the Galapagos
archipelago are similar to the inhabitants of the South American
mainland and not to the inhabitants of Africa? Because Galapagos
animals and plants — especially those famous birds, finches and
mocking-thrushes — had ancestors that came from the nearest mainland
rather than from across the world. When they got to the archipelago,
they set about evolving into their distinctive forms. Why do
organisms of very different species — the human and the chick, even —
have similar embryos? Because they have common ancestors and,
although natural selection tore the adults apart fitting them for
different niches, protected as they are in the womb there was little
reason for the embryos to evolve apart.
Again and again, Darwin backed up his theorizing with simple,
familiar examples. To confirm his suspicions about embryology, he
measured dogs and horses as pups and foals and as adults. Breeders
invariably told him that the distinctive breeds were as distinctive
in the young as in the adults, but careful measurements showed him
otherwise. Greyhound pups and bulldog pups are very similar, as are
racehorse and draft-horse foals. Why? Because, as in nature,
breeders select for adult forms and care little about the forms of
It is this simple familiarity that deceives so many people about
Origin, with its examples known to all and its friendly language, so
unlike the average science book. There is a reason for this style.
Darwin was a very skilled biologist, much respected by his peers,
but in another sense he was an amateur. He never worked for pay as a
professor or anything like that. He lived off the vast family
fortune, mainly from the Wedgwood pottery factory, founded by his
grandfather. All his life, Darwin respected and reflected this,
writing first for the approval of his family patrons, even after
they were long dead.
So Origin is deceptively simple. In the comfortable language of an
educated, middle-class Englishman, Darwin made a powerful case for
an idea that has rightly been characterized as the most important
ever discovered about the nature and status of the living world.
Michael Ruse co-edited the forthcoming "Cambridge Companion to On
the Origin of Species"
When scientists announced last week that they had deciphered the complete genetic playbook for the duck-billed platypus, the public reacted with considerably more enthusiasm than it had accorded similar bulletins about the sequencing of, say, the mustard plant, the mosquito or the wild chicken. A “fantastic response,” said Jennifer Marshall Graves of the Australian National University in Canberra, a principal author on the report. “More than I expected.”
One reason for the glowing reviews is that people love platypuses the way they love penguins and panda bears, as adorable, clumsy and nonthreatening creatures that remind them of kids playing dress-up. But the platypus trumps its plush-toy costars by adding a kind of Dada prankishness to the equation, what with its bill that looks like a Charlie Chaplin shoe, the leathery, thumb-sized eggs it insists on laying, the Daffy Duck webfeet outfitted with venomous spurs and the milk that dribbles down its unnippled chest. That the genetic code of the platypus proved to be as bizarrely pastiched as its anatomy enhanced the popular appeal of the report, published in the journal Nature.
Yet for researchers in the burgeoning field of comparative genomics, the real beauty of having spelled out all 2.2 billion chemical letters of the platypus’s genetic blueprint lies not with the freak-show charm of the animal but rather with its sublime ordinariness, positioned as almost a platonic abstraction of a mammal, yet one with enough specifically derived features to remind us that it is just an animal trying to make its way in the world. It is archaic and post-modern, primitive and refined. By studying the platypus and its close relatives, scientists hope to better understand the genesis and evolution of the entire mammalian family tree.
“Modern mammalian diversity is enormous,” said Zhe-Xi Luo, curator of vertebrate paleontology at the Carnegie Museum of Natural History in Pittsburgh, “but our view of that diversity has been heavily influenced by our focus on two of the three groups of mammals, the placentals and the marsupials.”
That fixation isn’t surprising, he said, given their numbers. Placental mammals that gestate their young internally, as do we and most of the pelts we know, account for 95 percent of the world’s 5,600 species of mammals, and marsupials like the kangaroo, koala and our very own opossum, whose young are born at a grublike stage and do most of their developing externally, often in a pouch, constitute nearly all the rest.
The third group of mammals, the monotremes, claims a measly three distinct animals, and all are indigenous to Australia and New Guinea: the duckbilled platypus and the long-beaked and short-beaked echidnas, also known as spiny anteaters. Yet this small club goes very deep, and with the sequencing of the platypus genome, Dr. Luo said, “the total scope of mammalian diversity” can now be explored.
The monotremes are considered the most ancient mammalian group, dating back to the Jurassic period, which began roughly 200 million years ago. They are not our direct ancestors, but rather split off from the rodenty line that gave rise to us and marsupials some 180 million years ago, with marsupials breaking away maybe 40 million years later.
However ancient the rupture, the last common ancestor between us and monotremes was clearly mammalian, for we all sport mammalian traits, some of us more luxuriously than others. The duckbilled platypus, for example, is jacketed in two layers of fine, dense fur, the better to keep it warm in its semi-aquatic existence, and “it’s the softest fur you can imagine,” said a co-author of the platypus paper, Wesley Warren of Washington University School of Medicine.
Monotremes also have a four-chambered heart, a mammalian jaw hinge and a set of tiny middle ear bones that, unlike in reptiles, are separated from the lower jaw and hence lend mammals their highly sensitive hearing. And though a platypus mother lacks nipples, the fluid that oozes from two round patches of skin on her belly is the same sort of rich blend of sugars, proteins, fatty acids, vitamins and antimicrobial agents lionized by La Leche.
Monotremes also possess features that hark back to a runty mammal’s lot at play among the giants of Jurassic park. They can dig themselves into the haven of a hole within moments. They are most active in the evening and at dawn, in contrast to the diurnal dinosaurs. They have true or vestigial spurs on their back legs, which the male platypus still packs with a snakelike venom. While the poisonous spearlets are now directed largely against rival males, the trait could well have served among ancestral monotremes as the equivalent of a bee’s sting, to ward off the Bigfeet that ever threatened to crush them.
At the same time, the monotremes still pay homage to their premammalian forebears. The group name, monotreme, means “one-holed,” and so echidnas and platypuses have the equivalent of a bird or reptile cloaca, a single all-purpose orifice for excretion, sex and the laying of eggs.
The laying of eggs is, of course, a monotreme’s clearest vinculum to a reptilian-avian mode of life. After digging herself an underground nest and padding it with vegetation, a female platypus lays one to three eggs and incubates them for about 10 days.
On hatching, the babies are barely the size of a gumdrop, and they will spend the next five months nursing in the burrow, emerging only when they are close to full-grown, maybe the size of a housecat. It’s time to start hunting for a living, to dive into a pond in search of crustaceans, which the platypus does with the help of chemoreceptors to smell the prey and electroreceptors to detect the minor electrical field surrounding the prey and mechanoreceptors to track movement of the prey and a toothless but tough horny bill for seizing and crushing the prey it has amply sensed.
“They’re voracious, curious creatures, constantly moving and nibbling on things,” Dr. Warren said.
For its part, the echidna is highly specialized for eating ants and termites, with a long pointed snout and a wormlike, sticky tongue.
In the specifics of their hunting gear, the platypus and echidna reveal their highly stylized sides, the kidskin fit between themselves and their niches, and the ways they have profoundly evolved since their ancestors and ours started loosening their jawbones and sweetening the glandular secretions with which they moistened their eggs. Monotremes are like the fantasy geezer aunt you never knew you had, breezing in from the other side of the world, with wild tales of the past and no plans for slowing down.
When it comes to science, creationists tend to struggle with reality. They believe, after all, that evolution by means of natural selection is false and that Earth is only a few thousand years old. They also believe that students who are taught a creationist view of biology — or who are taught to disregard the Darwinist view — are not being disadvantaged.
The Texas State Board of Education is again considering a science curriculum that teaches the “strengths and weaknesses” of evolution, setting an example that several other states are likely to follow. This is code for teaching creationism.
It has the advantage of sounding more balanced than teaching “intelligent design,” which the courts have consistently banned from science classrooms. It has the disadvantage of being nonsense.
The chairman of the Texas board, a dentist named Don McLeroy, advocates the “strengths and weaknesses” approach, as does a near majority of the board. The system accommodates what Dr. McLeroy calls two systems of science, creationist and “naturalist.”
The trouble is, a creationist system of science is not science at all. It is faith. All science is “naturalist” to the extent that it tries to understand the laws of nature and the character of the universe on their own terms, without reference to a divine creator. Every student who hopes to understand the scientific reality of life will sooner or later need to accept the elegant truth of evolution as it has itself evolved since it was first postulated by Darwin. If the creationist view prevails in Texas, students interested in learning how science really works and what scientists really understand about life will first have to overcome the handicap of their own education.
Scientists are always probing the strengths and weakness of their hypotheses. That is the very nature of the enterprise. But evolution is no longer a hypothesis. It is a theory rigorously supported by abundant evidence. The weaknesses that creationists hope to teach as a way of refuting evolution are themselves antiquated, long since filed away as solved. The religious faith underlying creationism has a place, in church and social studies courses. Science belongs in science classrooms.
Charles Darwin. (Richard Milner/European Pressphoto Agency)
In a week or so, the trumpets will sound, heralding the start of 18 months of non-stop festivities in honor of Charles Darwin. July 1, 2008, is the 150th anniversary of the first announcement of his discovery of natural selection, the main driving force of evolution. Since 2009 is the 200th anniversary of Darwin’s birth (Feb. 12), as well as being the 150th anniversary of the publication of his masterpiece, “On the Origin of Species” (Nov. 24), the extravaganza is set to continue until the end of next year. Get ready for Darwin hats, t-shirts, action figures, naturally selected fireworks and evolving chocolates. Oh, and lots of books and speeches.
But hold on. Does he deserve all this? He wasn’t, after all, the first person to suggest that evolution happens. For example, his grandfather, Erasmus Darwin, speculated about it towards the end of the 18th century; at the beginning of the 19th, the great French naturalist Jean-Baptiste Lamarck made a strong case for it. Lamarck, however, failed to be generally persuasive because he didn’t have a plausible mechanism — he could see that evolution takes place, but he didn’t know how. That had to wait until the discovery of natural selection.
Natural selection is what we normally think of as Darwin’s big idea. Yet he wasn’t the first to discover that, either. At least two others — a doctor called William Wells, and a writer called Patrick Matthew — discovered it years before Darwin did. Wells described it (admittedly briefly) in 1818, when Darwin was just 9; Matthew did so in 1831, the year that Darwin set off on board HMS Beagle for what became a five-year voyage around the world.
It was a few months after returning from this voyage that Darwin first began to consider seriously the possibility of evolution, or the “transmutation of species.” At this time he knew nothing of Wells’s and Matthew’s accounts of natural selection; indeed, both accounts languished in obscurity until after the “Origin” was published. (After the “Origin” appeared, Matthew wrote to a magazine to draw attention to his statements on the subject; he then proceeded to put “Discoverer of the Principle of Natural Selection” on the title pages of his books. This annoyed Darwin.)
By 1858, Darwin had spent more than 20 years studying plants and animals and thinking about evolution. He had filled notebook after notebook with his thoughts on how evolution works; he had, in 1844, written a short manuscript on the subject that was to be published in the event of his untimely death; and he had discussed evolution with a few close friends. But he had published nothing. (He had, however, published books on several other subjects, including an exhaustive study of barnacles, both living and extinct.) Then, in June of that year, Darwin received a package from a young man named Alfred Russel Wallace; in the package, Wallace enclosed a brief manuscript in which he outlined the principle of evolution by natural selection.
What happened next is famous in the history of biology. On July 1, 1858, Wallace’s manuscript, as well as a couple of short statements on natural selection by Darwin (a segment of the 1844 manuscript, and part of a letter he’d written in 1857), were read at a meeting of the Linnean Society in London. The meeting had been organized by some of Darwin’s scientific friends to establish his priority in the discovery.
Of the material presented that night, the manuscript by Wallace is, in some respects, the more impressive: it is clearer and more accessible. Yet it is Darwin we celebrate; it is Darwin who, like a god in a temple, sits in white marble and presides over the main hall at the Natural History Museum in London. Why?
The reason is the “Origin.” Without the publication of the “Origin” the following year, the meeting at the Linnean Society could well have passed unnoticed, the Darwin-Wallace statements going the same way as those by Matthew and Wells. Indeed, the meeting had so little impact at the time that, at the end of the year, the president of the Linnean Society said, “The year which has passed has not, indeed, been marked by any of those striking discoveries which at once revolutionize, so to speak, the department of science on which they bear.”
This is one of my all-time favorite quotations (and I am fond of using it) because it shows how, at the time, little significance was attached to the Linnean Society meeting. We see that meeting as important now because of what happened next: it galvanized Darwin into writing and publishing the “Origin.”
And the “Origin” changed everything. Before the “Origin,” the diversity of life could only be catalogued and described; afterwards, it could be explained and understood. Before the “Origin,” species were generally seen as fixed entities, the special creations of a deity; afterwards, they became connected together on a great family tree that stretches back, across billions of years, to the dawn of life. Perhaps most importantly, the “Origin” changed our view of ourselves. It made us as much a part of nature as hummingbirds and bumblebees (or humble-bees, as Darwin called them); we, too, acquired a family tree with a host of remarkable and distinguished ancestors.
The reason the “Origin” was so powerful, compelling and persuasive, the reason Darwin succeeded while his predecessors failed, is that in it he does not just describe how evolution by natural selection works. He presents an enormous body of evidence culled from every field of biology then known. He discusses subjects as diverse as pigeon breeding in Ancient Egypt, the rudimentary eyes of cave fish, the nest-building instincts of honeybees, the evolving size of gooseberries (they’ve been getting bigger), wingless beetles on the island of Madeira and algae in New Zealand. One moment, he’s considering fossil animals like brachiopods (which had hinged shells like clams, but with a different axis of symmetry); the next, he’s discussing the accessibility of nectar in clover flowers to different species of bee.
At the same time, he uses every form of evidence at his disposal: he observes, argues, compares, infers and describes the results of experiments he has read about, or in many cases, personally conducted. For example, one of Darwin’s observations is that the inhabitants of islands resemble — but differ subtly from — those of the nearest continents. So: birds and bushes on islands off the coast of South America resemble South American birds and bushes; islands near Africa are populated by recognizably African forms.
He argues that the reason for this is that new islands become colonized by beings from the nearest continents, and that the new inhabitants then begin evolving independently. He then asks: can animals and plants from the continents get to new islands, especially those that are far out at sea? To investigate this, he conducts experiments to see how long seeds from different plants can remain immersed in saltwater and still begin to grow. In short, he tests his reasoning over and over again.
He is also, in some respects, surprisingly far-seeing. The “Origin” does not just expound natural selection. It contains a wealth of additional ideas and hypotheses, some of which Darwin went on to elaborate in other books. Among them: sexual selection. This is the idea — and it remained controversial until recently — that males in many species are burdened with showy ornaments like enormous tails because the females of their species have, by repeatedly picking the showiest males as their mates, caused them to evolve them that way.
This is not to say that the “Origin” is flawless, or that Darwin was right in every respect. It isn’t, and he wasn’t. Nor is the book a definitive account of how evolution works. It wasn’t even definitive in his lifetime: he published six editions, revising, sometimes heavily, from one to the next. (In the third edition, which appeared in 1861, he introduced a historical sketch in which he discusses his precursors, including Matthew and Wells.) Yet his knowledge of the natural world is so immense, and the scrutiny to which he subjects his ideas is so thorough and scrupulous, that the “Origin” presents a grand new vision of the world. A vision that, as far as possible given the knowledge available at the time, he worked out in every detail. A vision that changed the world forever.
The historical events described here can be found in any biography of Darwin; I drew on Janet Browne’s — Knopf, in two volumes, “Voyaging” (1995) and “The Power of Place” (2002). The anecdote of Matthew annoying Darwin can be found on page 109 of “The Power of Place”; the quotation from the president of the Linnean Society can be found on page 42 of the same volume.
Many thanks to Dan Haydon, Horace Judson, Gideon Lichfield, Dmitri Petrov, Elizabeth Pisani and, especially, Jonathan Swire, for insights, comments, arguments and suggestions.
July 15, 2008
Scientist at Work | Edward O. Wilson
Taking a Cue From Ants on Evolution of Humans
By NICHOLAS WADE
The new fight is one Dr. Wilson has picked. It concerns a central feature of evolution, one with considerable bearing on human social behaviors. The issue is the level at which evolution operates. Many evolutionary biologists have been persuaded, by works like “The Selfish Gene” by Richard Dawkins, that the gene is the only level at which natural selection acts. Dr. Wilson, changing his mind because of new data about the genetics of ant colonies, now believes that natural selection operates at many levels, including at the level of a social group.
It is through multilevel or group-level selection — favoring the survival of one group of organisms over another — that evolution has in Dr. Wilson’s view brought into being the many essential genes that benefit the group at the individual’s expense. In humans, these may include genes that underlie generosity, moral constraints, even religious behavior. Such traits are difficult to account for, though not impossible, on the view that natural selection favors only behaviors that help the individual to survive and leave more children.
“I believe that deep in their heart everyone working on social insects is aware that the selection that created them is multilevel selection,” Dr. Wilson said.
Lucas Jackson/Reuters(The second part in a series celebrating Charles Darwin.)
It always happens the same way. A glance around the room to make sure no one else is listening. A clearing of the throat. A lowering of the voice to a conspiratorial tone. Then, the confession.
“I’ve never read ‘On the Origin of Species.’ I tried, but I thought it was boring.”
Thus, a number of eminent scientists — biologists all — have spoken. Or rather, whispered.
As the first major statement on evolution and how it works, Charles Darwin’s “On the Origin of Species” not only transformed the way we humans see ourselves. It marks the beginning of modern biology. But reading it is evidently not a prerequisite for a successful career in biology — not even for those studying evolution.
Which is not surprising. The book was written almost 150 years ago, and the subject has (needless to say) evolved since then. Moreover, the central enduring idea in the “Origin” — evolution by natural selection — can be learned from any number of textbooks.
Nonetheless, those confessions made me wonder. Does the “Origin” have anything fresh to say to a modern reader? Or is it simply of historical interest?
There is no doubt that the book is antiquated in several respects, and Darwin’s writing is — in my opinion — patchy. In places, his prose is clear, lyrical and glorious: as good as anything ever written by anyone. One of my favorite passages concerns the fact that some flowers are pollinated only by humble-bees (or bumblebees, as we call them now):
The number of humble-bees in any district depends in a great degree on the number of field-mice, which destroy their combs and nests; and Mr. H. Newman, who has long attended to the habits of humble-bees, believes that “more than two thirds of them are thus destroyed all over England.” Now the number of mice is largely dependent, as every one knows, on the number of cats; and Mr. Newman says, “Near villages and small towns I have found the nests of humble-bees more numerous than elsewhere, which I attribute to the number of cats that destroy the mice.” Hence it is quite credible that the presence of a feline animal in large numbers in a district might determine, through the intervention first of mice and then of bees, the frequency of certain flowers in that district!
But there are also passages that are long-winded, turgid and opaque. Often, these occur when Darwin is writing about subjects that were not understood at the time — such as what we now call genetics.
Beyond the fact that animals and plants tend to resemble their parents more than they resemble members of the population at large, Darwin knew nothing about how traits are inherited, or where genetic variation comes from. For his immediate purposes, this didn’t matter much. Natural selection will operate whenever all of three conditions are met. These are: (1) some of the differences between individuals are inherited differences, not due to differences in their environments; (2) more individuals are born than can survive; and (3) part of the reason at least some of the survivors make it is owing to the traits — a longer-than-average beak, say — that they inherited from their parents. For natural selection, then, what is important is that some differences are inherited; and this, Darwin could show. The breeding of animals such as dogs clearly illustrates that some traits are inherited; if they were not, distinct breeds like Belgian shepherds and Pekingese could not exist.
Darwin’s ignorance of genetics (of which he was well aware) means that many of the passages where he discusses it are tortuous, in part because he is describing a subject for which the very language did not exist. Darwin himself was the first to use “genetic” in a biological context; terms like “gene” wouldn’t be coined for another 50 years, and the structure of DNA — the stuff of which genes are made — wouldn’t be worked out for a further 40. He is also puzzled by observations that we can now easily explain. For example, he knew that bald dogs often have bad teeth, but was mystified as to why this should be so. (The reason is that, in the developing embryo, the same set of genes is involved in the initial formation of both teeth and hair. Mutations to those genes thus affect both traits.)
Two other factors make the “Origin” a demanding read today. The first is that Darwin’s own knowledge of the diversity of life is immense, and he assumes the reader will be familiar with a wide range of organisms — such as Asclepias (a group of flowering plants commonly known as milkweeds, for their thick milky sap) and corncrakes (stout land-dwelling birds related to waterbirds like moorhens). This means either skating over such words and just absorbing the gist of what he is saying, or spending a lot of time looking things up. Which is fine — but as a result, getting full meaning from the text requires a certain level of prior knowledge, a large dollop of enthusiasm, a good guidebook, or participation in a discussion group.
The other thing that makes the “Origin” tricky is that the text is stuffed with facts and speculations, and it is hard to know which of them are still taken seriously and which are obsolete. He thinks, for example, that all chickens bred by humans are descended from the wild Indian fowl (now known as Gallus gallus gallus). This is right. However, he also says that domestic dogs have been bred from a variety of ancestors in different parts of the world; this is no longer thought to be the case. All dogs are descended from the wolf.
Yet while this is sometimes frustrating, it is also inspiring. He has so many ideas! For instance, he mentions in passing that “it is a general law of nature (utterly ignorant though we be of the meaning of the law) that no organic being self-fertilises itself for an eternity of generations; but that a cross with another individual is occasionally — perhaps at very long intervals — indispensible.” This sentence alone has been the subject of countless doctoral theses; and, as far as we can tell, he’s basically right. The adoption of asexuality — which is what exclusive self-fertilization amounts to — almost always leads to a rapid extinction. The book, in other words, is a treasure trove of hypotheses and conjectures, many of which still await investigation.
Moreover, parts of the “Origin” still hold great insights. For example, to my mind Darwin’s discussion of instinctive behaviors is strikingly modern: he sees that instincts can evolve through natural selection in the same way that physical traits can. (By instincts he means behaviors that do not need to be learned — such as the tendency for a just-hatched cuckoo to heave any other eggs out of the nest it finds itself in.) He has a sophisticated view of how natural selection works, and the circumstances that make it powerful; indeed, his descriptions of the forces of nature — starvation, predation, competition and disease, to name a few — are as good as, or better than, those in most textbooks today. He appreciates that the biggest problems that most living beings face come not from features of the physical environment, such as climate, but from other organisms, whether of the same species or a different one. And in our current age of specialization, where deep knowledge of an animal or a plant often comes at the cost of broad knowledge of other members of the tree of life, it is deeply refreshing to come across writing that is so much about all of nature.
So, the difficulties notwithstanding, there are many reasons to tackle the “Origin.” Reasons above and beyond the fact that it is one of the most important books ever written, and central to our culture. But to me, perhaps the most important is that reading the “Origin” is a window into a mind. A rich and fertile mind, with a holistic view of nature. One that sees the interconnectedness of living beings — that cats can alter the number of flowers — long before ecology existed as a formal subject. A mind that sees the brutality of the natural world — the wasps that lay their eggs in the living bodies of caterpillars (the caterpillars are then eaten alive by the growing larvae), the stupendous death rates of most creatures — and sees that from the terrible slaughter, great beauty can arise:
Thus, from the war of nature, from famine and death, the most exalted object of which we are capable of conceiving, namely, the production of the higher animals, directly follows. There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.
(Note in response to a reader query: Darwin revised the text of the “Origin” extensively each time the book was republished in his lifetime; by the 6th (and last) edition, the text had evolved considerably. The final paragraph of the 6th edition differs from that of the first in that it includes mention of “the creator.” The relevant sentence of the 6th edition reads “…having been originally breathed by the creator into a few forms or into one…)”
The quotations are taken from the first edition of “On the Origin of Species.” The quotation about mice, bees, and cats comes from chapter 3 (page 74 of the Harvard University Press facsimile edition); the quotation about self-fertilization comes from chapter 4 (page 97 of the facsimile); the war of nature quotation is the final paragraph of the book (page 490).
(Note in response to a reader query: Darwin revised the text of the “Origin” extensively each time the book was republished in his lifetime; by the 6th (and last) edition, the text had evolved considerably. The final paragraph of the 6th edition differs from that of the first in that it includes mention of “the creator.” The relevant sentence of the 6th edition reads “…having been originally breathed by the creator into a few forms or into one…)”
The fact of Darwin being the first to use “genetic” in a biological context comes from “The Oxford English Dictionary,” second edition, 1989, volume VI, page 440. The date of introduction of “gene” comes from the same volume, page 428.
For the shared developmental pathways of hair and teeth, see pages 286-287, and the relevant notes, in Leroi, A. M. 2003. “Mutants: On Genetic Variety and the Human Body.” Viking.
For the origins of domestic chickens, see Fumihito, A., Miyake, T., Sumi, S.-I., Takada, M., Ohno, S., and N. Kondo. 1994. “One subspecies of the red junglefowl (Gallus gallus gallus) suffices as the matriarchic ancestor of all domestic breeds.” Proceedings of the National Academy of Sciences USA 91: 12505-12509. For the origins of domestic dogs, see Wayne, R. K. and E. A. Ostrander. 2007. “Lessons learned from the dog genome.” Trends in Genetics 23: 559-567.
Above, I say that “…Darwin knew nothing about how traits are inherited, or where genetic variation comes from. For his immediate purposes, this didn’t matter much.”
There is an interesting caveat to this. At the time Darwin was writing, inheritance was believed to be a sort of blending of the two parents, almost as though the factors of inheritance were a kind of soup. Darwin knew that blending wasn’t adequate to explain all of the patterns of inheritance he observed, but he was at a loss for an alternative. Under blending inheritance, populations should quickly become genetically uniform. When a population is genetically uniform, natural selection can’t operate. So for blending inheritance to allow natural selection to work, new genetic variation must be continually introduced at a very high rate. Or, to speak in modern terms, the mutation rate has be exceedingly high. Where variation comes from was thus one of Darwin’s major preoccupations. With the system of inheritance that actually exists — namely, genes — variation can be much more readily maintained in the population, and the problem goes away. For further discussion of blending inheritance and its implications for natural selection, and for Darwin’s gropings towards a particulate theory of inheritance, see chapter one of Fisher, R. A. 1999. “The Genetical Theory of Natural Selection: A Complete Variorum Edition” (edited by H. Bennett). Oxford University Press.
There are many editions of the “Origin”; I recommend the Harvard University Press facsimile of the first edition. There are also any number of readers’ guides and commentaries; as a good starting point, I recommend Ridley, M. 2005. “How to Read Darwin.” W.W. Norton.
Many thanks to Dan Haydon, Horace Judson, Gideon Lichfield, Dmitri Petrov and Jonathan Swire for insights, comments and suggestions.
There are interesting and related comments/responses to the article on the blog at:
July 15, 2008, 6:48 pm
Let’s Get Rid of Darwinism
(The third part in a series celebrating Charles Darwin.)
Charles Darwin was a giant. He did not merely write “On the Origin of Species” — one of the most important books ever written by anyone — in which he describes how evolution by natural selection works, and what some of its consequences and implications are. He also wrote — and this list is not exhaustive— a treatise on the formation of coral reefs that is still thought to be correct; a definitive monograph on barnacles, both extinct and extant; a book about how earthworms make soil; a now-classic text on carnivorous plants (the ones, like Venus fly-traps, that ensnare and digest insects); a book about the strange ways that orchids get themselves fertilized; and an account of the five years he spent aboard the ship HMS Beagle, which has become a classic of travel writing.
As if that wasn’t enough, he proposed sexual selection — the idea that decorations and ornaments, like peacocks’ tails, evolve because females in many species prefer to mate with the most beautiful males. Sexual selection has since become a major field of research in its own right.
In short, Darwin did more in one lifetime than most of us could hope to accomplish in two. But his giantism has had an odd and problematic consequence. It’s a tendency for everyone to refer back to him. “Why Darwin was wrong about X”; “Was Darwin wrong about Y?”; “What Darwin didn’t know about Z” — these are common headlines in newspapers and magazines, in both the biological and the general literature. Then there are the words: Darwinism (sometimes used with the prefix “neo”), Darwinist (ditto), Darwinian.
Why is this a problem? Because it’s all grossly misleading. It suggests that Darwin was the beginning and the end, the alpha and omega, of evolutionary biology, and that the subject hasn’t changed much in the 149 years since the publication of the “Origin.”
He wasn’t, and it has. Although several of his ideas — natural and sexual selection among them — remain cornerstones of modern evolutionary biology, the field as a whole has been transformed. If we were to go back in a time machine and fetch him to the present day, he’d find much of evolutionary biology unintelligible — at least until he’d had time to study genetics, statistics and computer science.
Oh, there would be so much to tell him! A full list would take me weeks to write out. But the obvious place to begin would be the discoveries of genetics, especially DNA. We’d have to explain that cells in each organism contain a code describing how to build that organism, written in chemical form — DNA — that evolutionary forces are constantly rewriting. Indeed, the study of DNA allows us to see the action of natural selection on a molecule-by-molecule basis. We can see the genes where natural selection acts to prevent evolutionary change, those where it drives change and those where it has no effect at all.
Then there’s the fusion of genetics with natural selection, which has enormously expanded our understanding of how natural selection can work. For example, it has led to the discovery that natural selection does not just shape individuals — the length of a beak, the color of a fin. It can also act on family groups, and thus drive the evolution of cooperation and other altruistic behaviors.
The reason is that evolutionary success can now be measured in terms of the number of genes an individual contributes to the next generation. Anyone who dies without reproducing does not directly contribute any. But because individuals have some genes in common with their family members, they can make an indirect genetic contribution if they help their relations to reproduce instead of reproducing themselves. Such “kin selection” is thought to have contributed to the evolution of the social insects — especially, ants, bees, wasps and termites — where only a few individuals reproduce and everyone else looks after the offspring.
We’d want to discuss evolution beyond natural selection — the other forces that can sometimes cause (or prevent) evolutionary change. For although natural selection is the only creative force in evolution — the only one that can produce complex structures such as wings and eyes — it is not the only force that affects which genes will spread, and which will vanish.
And, and, and.
What would he make of it all?
I think his reaction would be a mix of satisfaction and astonishment. Satisfaction: that natural selection has turned out to be such a powerful idea, explaining such a wide range of phenomena. Astonishment: for the same reason. He would, I think, be fascinated by the weird natural history that has been discovered in the past 150 years — such as Wolbachia, bacteria that pervert the reproduction of insects for their own ends. (Wolbachia can have a number of effects, but one of the most common is to kill all a female’s sons. The reason is that sons don’t transmit Wolbachia, so from Wolbachia’s point of view, they are a waste of space.) I’m not sure he’d enjoy analyzing DNA sequences — he might find it a bit too abstracted from the living organism — but I think he’d be delighted to learn the results. I think he would be shocked by how much we know about the so-called model organisms — worms, toads, fruit flies, mice, humans and the bacterium E. coli — and how little we know about everything else. And I think he’d be startled by the nature of scientific research — the scale of the enterprise, the cost, the pressures to publish and the degree of specialization that results. His brand of science — 20 years of thinking about a problem before publishing — could not be done today.
But I digress. To return to my argument: I’d like to abolish the insidious terms Darwinism, Darwinist and Darwinian. They suggest a false narrowness to the field of modern evolutionary biology, as though it was the brainchild of a single person 150 years ago, rather than a vast, complex and evolving subject to which many other great figures have contributed. (The science would be in a sorry state if one man 150 years ago had, in fact, discovered everything there was to say.) Obsessively focusing on Darwin, perpetually asking whether he was right about this or that, implies that the discovery of something he didn’t think of or know about somehow undermines or threatens the whole enterprise of evolutionary biology today.
It does not. In the years ahead, I predict we will continue to refine our understanding of natural selection, and continue to discover new ways in which it can shape genes and genomes. Indeed, as genetic data continues to flood into the databanks, we will be able to ask questions about the detailed workings of evolution that it has not been possible to ask before.
Yet all too often, evolution — insofar as it is taught in biology classes at all — is taught as the story of Charles Darwin. Then the pages are turned, and everyone settles down to learn how the heart works, or how plants make energy from sunshine, or some other detail. The evolutionary concepts that unify biology, that allow us to frame questions and investigate the glorious diversity of life — these are ignored.
Darwin was an amazing man, and the principal founder of evolutionary biology. But his was the first major statement on the subject, not the last. Calling evolutionary biology “Darwinism,” and evolution by natural selection “Darwinian” evolution, is like calling aeronautical engineering “Wrightism,” and fixed-wing aircraft “Wrightian” planes, after those pioneers of fixed-wing flight, the Wright brothers. The best tribute we could give Darwin is to call him the founder — and leave it at that. Plenty of people in history have had an -ism named after them. Only a handful can claim truly to have given birth to an entire field of modern science.
A full account of the range of Darwin’s activities and accomplishments can be found in any biography. Many publications are guilty of the “Was Darwin wrong?” trope, and some of the biggest quarrels in modern evolutionary biology have concerned the validity of “non-Darwinian” evolution. A number of popular accounts discuss aspects of modern evolutionary biology; one of the best is “The Ancestor’s Tale,” by Richard Dawkins. Much has been written about male-killing by Wolbachia; see, for example, Jiggins, F. M., Hurst, G. D. D., Dolman, C. E., and Majerus, M. E. N. 2000. “High-prevalence male-killing Wolbachia in the butterfly Acraea encedana.” Journal of Evolutionary Biology 13: 495-501.
This article was inspired (as so many others have been) by a conversation with Oliver Morton — many thanks, as always. Thanks, too, to Dan Haydon, Gideon Lichfield
Last week, I discussed how evolutionary biology has changed since 1859, the year Darwin first published “On the Origin of Species.” But the subject of evolution isn’t the only thing that’s changed since then. There’s been plenty of actual evolution, too. For although we tend to think of evolutionary change as being something that only takes place over the course of millions of years, it isn’t. It’s going on here, now, all around us. So, this week, I thought I’d round up some examples of recent evolutionary change in nature. (What do I mean by recent? Within the last 40 years.)
I’m not intending to be comprehensive — that would take a book or two. Instead, I want to sketch a few examples of natural selection that have caught my fancy, and through them consider different aspects of evolutionary change, and what it takes to show it.
Galápagos finches. No discussion of evolution in nature would be complete without mention of the evolution of beak size in finches in the Galápagos archipelago.
Every year since 1973, large numbers of medium ground finches (Geospiza fortis) living on the island of Daphne Major have been marked, weighed and measured, and so have their chicks. In these finches, survival largely depends on the ability to open seeds; this depends on beak size. Bigger beaks allow the opening of larger seeds. How many seeds there are depends on the weather; some years seeds of all sizes are abundant, and the finches thrive. In other years, most seeds are scarce, and many birds die. Large-scale death affects the genetic make-up of the population, because both beak size and body size has a large genetic component. If all the birds with smaller than average beaks die in a given year, they take their genes with them.
Over the course of 30 years, annual measurement of finches shows that both body size and beak size evolved significantly. But they didn’t do so in a smooth, consistent fashion. Instead, natural selection jittered about, often changing direction from one season to the next.
As the abundance of different seeds fluctuated, so too did the beak sizes. One year, larger beaks were more successful; then it was smaller beaks. Over time, the average shape of the beak kept shifting, but it did so in an unpredictable, erratic sort of way, like a drunk man staggering about. Thus, some of the most dramatic changes were later reversed, and if beaks had only been measured at the beginning and at the end of the thirty years, the total amount of evolutionary change would have been underestimated. (Beak size has continued to evolve: the arrival on the island of a competitor for large seeds has subsequently favored small beak sizes in Geospiza fortis. Many individuals with larger beaks starved to death.)
Field mustard. Between 2000 and 2004, southern California had a severe drought. For many plants, including field mustard (a scrawny annual plant with little yellow flowers), a drought means a shorter growing season. A shorter growing season means that plants that flower earlier are more likely to leave seeds than plants that flower later — which are in danger of dying before they’ve finished reproducing. Since flowering time has a large genetic component, a drought — by favoring plants that flower earlier — could cause an evolutionary shift towards early flowering.
Yes. The beauty of plants is that they make seeds — small packets of genes that can be stored for a period. This means that the genes of the past can, in principle, be compared directly with the genes of today. And an experiment in which field mustard plants grown from seeds collected in 1997 and in 2004 were planted together, under controlled conditions, showed clear differences in flowering times: the plants from 2004 flowered significantly earlier.
Moreover, in both years, seeds were collected from two sites, one where the soil is sandy and doesn’t hold water well, and the other where the soil stays wet for longer. As you’d expect, plants from the dry site showed a more dramatic shift than plants from the wet site. In the course of just 7 years, then, natural selection caused the plants to evolve an earlier flowering time.
Croatian lizards. In 1971, five pairs of adult wall lizards (Podarcis sicula) were brought to the tiny Croatian island of Pod Mrčaru from the nearby island of Pod Kopište. These five pairs have since given rise to a thriving lizard population — and one that has developed some interesting differences from the lizards that live on Kopište.
Lizards on Mrčaru now have larger heads and stronger bites than those living on Kopište, and they eat far more in the way of leaves and other plant material. Whereas the diet of native Kopište lizards is only about 7 percent plant matter, Mrčaru lizards are much more prone to a vegetarian habit. In spring, their diet is about 34 percent from plants; in summer that almost doubles, to 61 percent.
Plants are hard for animals to digest, and most plant-eaters rely on micro-organisms to help them. They also, typically, have complicated stomachs — think of the fermentation chambers in a cow, or the enlarged crop of that strange leaf-eating bird, the hoatzin. Intriguingly, the Mrčaru lizards appear to have evolved something similar. Their stomachs now have cecal valves, which divide the stomach into compartments, allowing for slower digestion and fermentation. Cecal valves are rare among lizards and snakes: fewer than 1 percent of species have them. At the same time, the Mrčaru lizards have acquired some novel micro-organisms in their guts (but whether these are helping break down plant fibers, or are some sort of sinister parasite, remains to be seen).
This study is one of the most intriguing I’ve come across. It suggests that arrival in a new environment can result in dramatic changes to an organism within fewer than 40 lifetimes. But so far, the basis of these various changes remains unknown: there’s an outside possibility that they are induced by leaf eating, and are thus due to the environment rather than genetics. (This seems unlikely — even lizards that are just hatched, and haven’t had a chance to do much eating, have the valves. But without doing the genetics, we can’t be sure; until that has been looked at, the changes cannot definitely be attributed to natural selection.) For now, natural selection for efficient plant-eating is the main suspect for this whole suite of changes, but the case is not yet closed.
Other examples. I don’t have space to go into other examples in detail, but to give a sense of what else is out there, here’s a partial list.
The fruit fly Drosophila subobscura has been evolving bigger wings in higher latitudes in North and South America; mosquitoes that live in pitcher plants hunker down for the winter later in the year than they used to; in a forest in southern England, great tits have been shrinking (great tits are songbirds).
Double the time frame to the past 80 years, and I’d have to add many more; of these, my favorite is the decline in head size of Australian frog-eating snakes in response to the arrival of poisonous toads in 1935 (a smaller head makes it harder to eat a deadly toad). And I haven’t even begun to mention the countless examples of pests that have evolved resistance to pesticides and bacteria that have evolved resistance to antibiotics, nor the thousands of laboratory experiments showing evolution in the simple environments of test tubes and petri dishes. Also omitted: several examples of new species that are in the process of forming (I want to look at these in a future column).
In short, evolution never takes a vacation: it’s going on all the time.
Yet we tend not to notice it. Why? The finches can help us here. That study tells us two things. First, from one year to the next, even the most dramatic changes are, to our eyes, small — which is to say, you have to measure them to detect them. The reason is that although birds differ from one another in their abilities to handle the various seeds, the differences are subtle. It’s not as if one bird has a beak 100 times mightier than another’s. When you add to this the tendency of natural selection to jerk around, it’s no surprise that we often don’t notice evolution as it happens. It also sheds light on why changes in the fossil record often appear to be slow: these studies show that change can be continual without really getting far from the starting point. Second, getting data as good as that is hard work. Most datasets are not so complete or robust.
At least one other lesson can be drawn from all these studies. Natural selection has its most dramatic effects when an organism’s environment is perturbed in some sustained way — prolonged droughts, the arrival of species that compete for food, warmer winters, the use of pesticides. If we humans continue to increase our impact on the globe, we’re likely to see lots more evolution. And soon.
For beak size in Galápagos finches, see Grant, P. R. and Grant, B. R. 2002. “Unpredictable evolution in a 30-year study of Darwin’s finches.” Science 296: 707-711 and Grant, P. R. and Grant, B. R. 2006. “Evolution of character displacement in Darwin’s finches.” Science 313: 224-226. For evolution of flowering time in field mustard, and for its genetic basis, see Franks, S. J., Sim, S. and Weis, A. E. 2007. “Rapid evolution of flowering time by an annual plant in response to a climate fluctuation.” Proceedings of the National Academy of Sciences USA 104: 1278-1282. For the evolution of cecal valves in Croatian lizards, see Herrel, A. et al 2008. “Rapid large-scale evolutionary divergence in morphology and performance associated with exploitation of a different dietary resource.” Proceedings of the National Academy of Sciences USA 105: 4792-4795.
For wing size in fruit flies, see Huey, R. B. et al 2000. “Rapid evolution of a geographic cline in size in an introduced fly.” Science 287: 308-309 and Gilchrist, G. W. et al 2004. “A time series of evolution in action: a latitudinal cline in wing size in South American Drosophila subobscura.” Evolution 58: 768-780. For hunkering down time in mosquitoes, see Bradshaw, W. E. and Holzapfel, C. M. 2001. “Genetic shift in photoperiodic response correlated with global warming.” Proceedings of the National Academy of Sciences USA 98: 14509-14511. For body size in great tits, see Garant, D. et al 2005. “Evolution driven by differential dispersal within a wild bird population.” Nature 433: 60-65. For head size in Australian snakes, see Phillips, B. L. and Shine, R. 2004. “Adapting to an invasive species: toxic cane toads induce morphological change in Australian snakes.” Proceedings of the National Academy of Sciences USA 101: 17150-17155.
Many thanks to Dan Haydon, Gideon Lichfiel
August 13, 2008
Optimism in Evolution
By OLIVIA JUDSON
When the dog days of summer come to an end, one thing we can be sure of is that the school year that follows will see more fights over the teaching of evolution and whether intelligent design, or even Biblical accounts of creation, have a place in America’s science classrooms.
In these arguments, evolution is treated as an abstract subject that deals with the age of the earth or how fish first flopped onto land. It’s discussed as though it were an optional, quaint and largely irrelevant part of biology. And a common consequence of the arguments is that evolution gets dropped from the curriculum entirely.
This is a travesty.
It is also dangerous.
Evolution should be taught — indeed, it should be central to beginning biology classes — for at least three reasons.
First, it provides a powerful framework for investigating the world we live in. Without evolution, biology is merely a collection of disconnected facts, a set of descriptions. The astonishing variety of nature, from the tree shrew that guzzles vast quantities of alcohol every night to the lichens that grow in the Antarctic wastes, cannot be probed and understood. Add evolution — and it becomes possible to make inferences and predictions and (sometimes) to do experiments to test those predictions. All of a sudden patterns emerge everywhere, and apparently trivial details become interesting.
The second reason for teaching evolution is that the subject is immediately relevant here and now. The impact we are having on the planet is causing other organisms to evolve — and fast. And I’m not talking just about the obvious examples: widespread resistance to pesticides among insects; the evolution of drug resistance in the agents of disease, from malaria to tuberculosis; the possibility that, say, the virus that causes bird flu will evolve into a form that spreads easily from person to person. The impact we are having is much broader.
For instance, we are causing animals to evolve just by hunting them. The North Atlantic cod fishery has caused the evolution of cod that mature smaller and younger than they did 40 years ago. Fishing for grayling in Norwegian lakes has caused a similar pattern in these fish. Human trophy hunting for bighorn rams has caused the population to evolve into one of smaller-horn rams. (All of which, incidentally, is in line with evolutionary predictions.)
Conversely, hunting animals to extinction may cause evolution in their former prey species. Experiments on guppies have shown that, without predators, these fish evolve more brightly colored scales, mature later, bunch together in shoals less and lose their ability to suddenly swim away from something. Such changes can happen in fewer than five generations. If you then reintroduce some predators, the population typically goes extinct.
Thus, a failure to consider the evolution of other species may result in a failure of our efforts to preserve them. And, perhaps, to preserve ourselves from diseases, pests and food shortages. In short, evolution is far from being a remote and abstract subject. A failure to teach it may leave us unprepared for the challenges ahead.
The third reason to teach evolution is more philosophical. It concerns the development of an attitude toward evidence. In his book, “The Republican War on Science,” the journalist Chris Mooney argues persuasively that a contempt for scientific evidence — or indeed, evidence of any kind — has permeated the Bush administration’s policies, from climate change to sex education, from drilling for oil to the war in Iraq. A dismissal of evolution is an integral part of this general attitude.
Moreover, since the science classroom is where a contempt for evidence is often first encountered, it is also arguably where it first begins to be cultivated. A society where ideology is a substitute for evidence can go badly awry. (This is not to suggest that science is never distorted by the ideological left; it sometimes is, and the results are no better.)
But for me, the most important thing about studying evolution is something less tangible. It’s that the endeavor contains a profound optimism. It means that when we encounter something in nature that is complicated or mysterious, such as the flagellum of a bacteria or the light made by a firefly, we don’t have to shrug our shoulders in bewilderment.
Instead, we can ask how it got to be that way. And if at first it seems so complicated that the evolutionary steps are hard to work out, we have an invitation to imagine, to play, to experiment and explore. To my mind, this only enhances the wonder.
Olivia Judson, a contributing columnist for The Times, writes The Wild Side at nytimes.com/opinion.
August 19, 2008
Life Is Short...
By NATALIE ANGIER
Sure, Michael Phelps may have snapped a string of Olympic records like so many Rice Krispies in milk, but what was this child of Poseidon up against, anyway? Elite human athletes from 250 countries.
A small, speckled, asparagus-green chameleon of Madagascar, by contrast, holds a world speed record among just about all of the nearly 30,000 different animals equipped with four limbs and a backbone.
Admittedly, it’s not a record many of us would aspire to best. As researchers recently reported in The Proceedings of the National Academy of Sciences, the entire life span of the Furcifer labordi chameleon — from the moment of conception to development in the egg, hatching, maturation, breeding and right through to its last little lizardly thud to the ground — clocks in at barely a year.
That hypercondensed biography, the scientists said, may well make the chameleon the shortest-lived tetrapod on Earth, a creature chronologically more like a butterfly or a sea squirt than like the other reptiles, frogs, birds and mammals with which it is taxonomically bundled.
Equally bizarre, said Christopher J. Raxworthy, an author of the new report, the chameleon spends some two-thirds of its abbreviated existence as an egg buried in sand, with a mere 16 to 20 weeks allocated to all post-shellular affairs.
Moreover, the chameleons operate by a synchronized schedule, hatching, growing, mating and dying at more or less the same times and at the same pace throughout the year. As a result, said Dr. Raxworthy, associate curator of herpetology at the American Museum of Natural History, “if you go into a forest during the dry season, the whole population of chameleons there will be represented by eggs.”
Counterintuitive though it may seem, the extremity of F. labordi’s schedule could prove valuable for tracking down genes and other biological factors that promote longevity. The researchers observed that the chameleon is not merely short-lived as a matter of averages. It is an obligate annual species, destined for death after a single spin around the sun, and that stated fate differs markedly from the varying degrees of perenniality found throughout the tetrapod clan.
“There are about a dozen lizard species known to be short-lived, in which a good proportion of individuals die off by a year,” said Kristopher B. Karsten of the zoology department at Oklahoma State University, another author of the report. “But there are always some that make it to the next year, so the species’ maximal longevity is greater than one year.”
No such luck for our bug-eyed Malagasy friends, which live in the arid, scrubby southwestern region of the giant island. “Once they reach the end of the season,” Dr. Karsten said, “they’re done,” and they will drop from the trees with the papery grace of autumn leaves.
Assuming the execution orders are somehow part of the chameleon’s program, researchers might be able to identify the specific genetic or hormonal assassins in lizard cells, find their analogues in human cells and put a cap in them.
The new work also underscores the growing use of so-called life history theory to trace the history and contours of life on Earth.
Scientists have determined that many essential features of an animal’s portfolio are linked, among them whether at birth it looks fetal and helpless like a newborn kitten or precocious and competent like a neonatal giraffe; how big the average litter is; the speed with which the animal reaches sexual maturity; the length of time between births; and the pace at which an adult ages.
Try to improve or optimize one of these parameters and you end up paying somewhere else along the line. “One of the most robust things to come out of life history theory is that trade-offs exist,” said Steven N. Austad, the author of “Why We Age” and a professor of cellular and structural biology at the University of Texas Health Science Center.
“If you increase the number of young, the cost is often accelerated aging. If you get something that lives longer, you get costs early in life, with lower fertility and even sterility.”
Selective pressures in the environment push species toward one life history course or another. One example is that if you’re a species in which the great majority of adults end up being killed by predators or disease, it’s best to invest your resources in breeding early and often and not to bother worrying about long-term needs like a robust DNA repair system. And so it is that rodents beloved by carnivores everywhere have high fecundity and relatively poor longevity.
If you’re a species in which infant and juvenile mortality is comparatively great, as it is with giant tortoises, for example, the emphasis is often on making the best of adulthood, with delayed maturity and extended life spans.
Catastrophic extrinsic changes may quickly rewrite a species’ game plan. In another new report from the National Academies journal, researchers presented evidence that Tasmanian devils, the largest of all carnivorous marsupials, have responded to an epidemic of fatal transmissible tumors among adults with a 16-fold increase in precocious puberty among the young. If you’re likely to be gone tomorrow, you’d better start begetting today.
Furcifer labordi’s extreme life history likewise seems born of extreme adversity and volatility. The chameleon is one of the smallest members of its genus, and adults are readily, avidly snacked on by birds and snakes. The local climate is harsh and unpredictable, lowering the odds of survival beyond a single rainy season.
In addition, the rainy season, which begins in November, when the chameleons hatch en masse, is brief and must be frantically exploited. The young coil-tongued lizards immediately start lassoing insects, and they eat so much, Dr. Raxworthy said, “that they practically grow in front of your very eyes.”
By January the chameleons are ready to mate, a nasty, often violent business of males fighting males, females fighting males, and all of them wishing they were somewhere else. Despite their cuteness, Dr. Raxworthy said, “chameleons can be very antisocial, and if you crowd them, they’ll happily fight to the death.”
Dr. Karsten suspects that Furcifer labordi’s compressed breeding season fosters such high levels of aggression that the chameleons die, in part, of hormone overdose.
Another athletic career cut tragically short by steroids.
August 24, 2008
A Teacher on the Front Line as Faith and Science Clash
By AMY HARMON
ORANGE PARK, Fla. — David Campbell switched on the overhead projector and wrote “Evolution” in the rectangle of light on the screen.
He scanned the faces of the sophomores in his Biology I class. Many of them, he knew from years of teaching high school in this Jacksonville suburb, had been raised to take the biblical creation story as fact. His gaze rested for a moment on Bryce Haas, a football player who attended the 6 a.m. prayer meetings of the Fellowship of Christian Athletes in the school gymnasium.
“If I do this wrong,” Mr. Campbell remembers thinking on that humid spring morning, “I’ll lose him.”
In February, the Florida Department of Education modified its standards to explicitly require, for the first time, the state’s public schools to teach evolution, calling it “the organizing principle of life science.” Spurred in part by legal rulings against school districts seeking to favor religious versions of natural history, over a dozen other states have also given more emphasis in recent years to what has long been the scientific consensus: that all of the diverse life forms on Earth descended from a common ancestor, through a process of mutation and natural selection, over billions of years.
But in a nation where evangelical Protestantism and other religious traditions stress a literal reading of the biblical description of God’s individually creating each species, students often arrive at school fearing that evolution, and perhaps science itself, is hostile to their faith.
Some come armed with “Ten questions to ask your biology teacher about evolution,” a document circulated on the Internet that highlights supposed weaknesses in evolutionary theory. Others scrawl their opposition on homework assignments. Many just tune out.
With a mandate to teach evolution but little guidance as to how, science teachers are contriving their own ways to turn a culture war into a lesson plan. How they fare may bear on whether a new generation of Americans embraces scientific evidence alongside religious belief.
“If you see something you don’t understand, you have to ask ‘why?’ or ‘how?’ ” Mr. Campbell often admonished his students at Ridgeview High School.
Yet their abiding mistrust in evolution, he feared, jeopardized their belief in the basic power of science to explain the natural world — and their ability to make sense of it themselves.
September 2, 2008
By CARL ZIMMER
NEW HAVEN — By day, Thomas Near studies the evolution of fish, wading through streams in Kentucky and Mississippi in search of new species. By night, Dr. Near, an assistant professor at Yale, is a heavy-duty gamer, steering tanks or playing football on his computer. This afternoon his two lives have come together.
On his laptop swims a strange fishlike creature, with a jaw that snaps sideways and skin the color of green sea glass. As Dr. Near taps the keyboard, it wiggles and twists its way through a busy virtual ocean. It tries to eat other creatures and turns its quills toward predators that would make it a meal.
The chairman of Dr. Near’s department, Richard Prum, watches him play and worries about his reckless lunges.
“You’re just attacking them?” he asks as Dr. Near tries to eat a fat purple worm that looks too dangerous to bother.
“If you kill them, you unlock their parts,” Dr. Near explains. But then the purple worm sticks its syringelike mouth into Dr. Near’s beast and begins to drain its innards. “Uh-oh, I’m about to die,” he says. The screen fades to black.
The next time, Dr. Near’s luck changes. He gains enough points to move to the next level of the game. His creature grows a brain. “Oh man, it’s like I graduated college,” he says. Dr. Near can now alter his creature. He stretches the body to give it a neck. He adds a pair of kangaroolike legs.
His creature — or, rather, a swarm of his creatures — charge out of the ocean and onto land. Dr. Near pushes back the laptop as his creatures find a place to make their nest and lay eggs. “So that’s pretty cool,” he says with a grin not often seen on a professor.
Dr. Near and Dr. Prum have spent a few evenings testing out Spore, one of the most eagerly anticipated video games in the history of the industry. After years of rumors, the game goes on sale Friday. Spore’s designer, Will Wright, is best known for creating a game called the Sims in 2000. That game, which let players run the lives of a virtual family, has sold 100 million copies. It is among the best-selling video game franchises of all time, in an $18-billion-a-year industry that is now bigger than Hollywood.
Spore, produced by Electronic Arts, promises much more than the day-to-day adventures of simulated people. It starts with single-cell microbes and follows them through their evolution into intelligent multicellular creatures that can build civilizations, colonize the galaxy and populate new planets.
Unlike the typical shoot-them-till-they’re-all-dead video game, Spore was strongly influenced by science, and in particular by evolutionary biology. Mr. Wright will appear in a documentary next Tuesday on the National Geographic Channel, sharing his new game with leading evolutionary biologists and talking with them about the evolution of complex life.
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