Teaching Evolution

A blog devoted to teaching evolution, both in our schools and in our communities.

Thursday, March 31, 2005

Ebert on Imax

Roger Ebert, a staunch defender of evolution and admirer of Charles Darwin, has weighed in on the controversy of Imax theaters backing off from showing documentaries that discuss evolution:
Surely moviegoers deserve the right to decide for themselves what movies to see? "Volcanoes of the Deep Sea," according to the AP, "makes a connection between human DNA and microbes inside undersea volcanoes." It says that if life could evolve under such extreme circumstances, it might help us understand evolution all over the planet.

This is not a controversial opinion. The overwhelming majority of all scientists everywhere in the world who have studied the subject would agree with it. Although discussion continues about the mechanics of evolution, there is no reputable doubt about the existence of DNA and the way in which it functions.

Yes, there is “creationist science,” an attempt to provide a scientific
footing for beliefs which should be a matter of faith. Creationists say
evolution is “only a theory,” and want equal time for their theories,
one of which is that God created the earth from scratch in six days,
and rested on the seventh.

Evolution is indeed a theory. Creationism is a belief, not a theory. In science, a theory is a hypothesis that has withstood the test of time and the challenge of opposing views. It is not simply somebody's notion about something. The creationist belief cannot withstand such tests and challenges; it exists outside the world of science altogether.

Wednesday, March 30, 2005

Sounds Like a Stimulating Discussion

The ultra-conservative Heritage Foundation will soon host a forum on Intelligent Design. My favorite blogger, Kevin Drum, has the details.

Tuesday, March 29, 2005

Was Darwin Wrong?

The November 2004 National Geographic had a great cover story, giving an emphatic no to its headline question. Only a brief excerpt of the article is online; it's worth reading, but it's better to find the whole magazine. Writer David Quammen has been nominated for a National Magazine Award.

Monday, March 28, 2005

As One Gene Changes, So Does Whole Skeleton

Evolution is a gradual process that occasionally includes sudden leaps. One of those sudden leaps has been found in the genes of a certain type of fish called sticklebacks:
scientists have now found that changes in a single gene can produce major changes in the skeletal armor of fish living in the wild....Using genetic crosses between armored and unarmored fish from wild populations, the research team found that one gene is what makes the difference.

Friday, March 25, 2005

Charles Darwin: The Power of Place Part 2-Experimenter

One of my favorite things about Darwinism is the way it applies to subjects beyond biology and anthropology. In Part 2 of Charles Darwin: The Power of Place, Janet Browne writes,
[B]y now some of the most notable nineteenth-century thinkers were contemplating the inner recesses of Darwin's theory and pulling out of it some of the threads that would lead them towards the modern world….[S]everal key intellectuals commended Darwin's method of scientific reasoning, a style depending more on the accumulation of probabilities, and on analogy, than on the classic form of proof by demonstration.

John Stuart Mill praised Darwin's "unimpeachable example of a legitimate hypothesis." The blind Cambridge economist Henry Fawcett began teaching and discussing the Origin of Species to the mathematical and economic community. Karl Marx wrote that "Darwin's work is most important and suits my purpose in that it provides a basis in natural science for the historical class struggle." Alfred Tennyson altered In Memoriam after reading Darwin, changing the line that read "Since Adam left his garden yet" to "Since our first sun arose and set." The philologist Friedrich Max Muller suggested that natural selection could have applied to ancient languages. Shortly before his death in 1862 Henry David Thoreau was captivated by Darwin's work.

Still, just as today, Darwin couldn't convince those who closed their minds to his idea. The Australian museum curator Frederick McCoy insisted that if he could get a gorilla skin for his museum, anyone who looked at it would realize that Darwin's view that man and gorilla were relatives was nonsense.

Darwin had a fascination with the American Civil War, and he was such an adamant supporter of the North that he occasionally alienated correspondents who differed with him over the goings on across the Atlantic. Shortly after Lincoln's assassination, Darwin wrote to an American friend,

We continue to be deeply interested on American affairs; indeed I care for nothing else in the Times. How egregiously wrong we English were in thinking that you could not hold the South after conquering it. How well I remember thinking that Slavery would flourish for centuries in your Southern States.

Darwin always considered himself a passionate opponent of slavery, but Browne points out that he wasn't as introspective on the subject as he might have been:

Although he supported the anti-slavery cause more completely than any other social principle in his life, it was nevertheless relatively easy for him, quietly situated in an English village and buttressed by a private income, to advocate a moral crusade in America. Conveniently, he forgot the colonial and industrial sources of British economic wealth, forgot that his own stocks and shares rested on the manual labour of railway navies, miners, indentured millhands, and plantation coolies.

Darwin's core belief that all men are created equal also helped him to avoid the pitfall of so many 19th Century evolutionists who tried to turn the theory of natural selection into evidence of the superiority of certain races.

Physical illness was such a serious problem throughout Darwin's life that Browne titles Chapter 7 "Invalid." Darwin often complained about stomach problems and was frequently confined to bed for long periods of time. But he used these times to his advantage, often getting great amounts of research done when no one would disturb him because he was sick. He often found that his illnesses were a convenient excuse to get out of going to some of the events that British society expected a man of Darwin's stature to attend.

The most common phrase associated with (and, sadly, the only thing many people know about) evolution is "survival of the fittest." Browne writes about the way the phrase, first coined by Herbert Spencer and championed by Alfred Russel Wallace, finally worked its way into Darwin's writing when he published a fifth edition of his most famous work.

At Wallace's urging, Darwin…used for the first time in the Origin of Species Spencer's phrase "survival of the fittest," although remarking that the benefits of a change in wording so late in the day could only be limited. "I fully agree with all that you say on the advantages of H. Spencer's excellent expression of the survival of the fittest," he observed.


Yet neither Darwin, Spencer, nor Wallace apparently noticed how far the expression was replete with circular reasoning, nearly self-defining as a philosophical and biological tautology, in which the fit survive and the survivors are fit.

Darwin respected Wallace enough to use "survival of the fittest," in his Origin, but he later began to question Wallace's intellect when Wallace became fascinated with mysticism and psychics, attending a séance on more than one occasion. "It astonished him," Browne writes, "That an observational naturalist of Wallace's stature could be taken in by what he regarded as obvious fictions."

Browne also reproduces two pages of an original copy of Darwin's Origin, in which Wallace had gone through by hand, crossed off every repetition of "natural selection," and written "survival of the fittest" in its place. Even when you're a genius of Darwin's caliber, someone else always thinks he's smarter.

Wednesday, March 23, 2005

A Plant Can Fix Its Flawed Gene

Scientists at Purdue University have discovered that plants that inherit a defective gene from both parents can also inherit a corrected version of the gene from some earlier generation of ancestors. As the New York Times reports,

The finding implies that some organisms may contain a cryptic backup copy of their genome that bypasses the usual mechanisms of heredity. If confirmed, it would represent an unprecedented exception to the laws of inheritance discovered by Gregor Mendel in the 19th century. Equally surprising, the cryptic genome appears not to be made of DNA, the standard hereditary material.

The discovery also raises interesting biological questions - including whether it gets in the way of evolution, which depends on mutations changing an organism rather than being put right by a backup system.


The finding poses a puzzle for evolutionary theory because it corrects mutations, which evolution depends on as generators of novelty. Dr. Meyerowitz said he did not see this posing any problem for evolution because it seems to happen only rarely. "What keeps Darwinian evolution intact is that this only happens when there is something wrong," Dr. Surridge said.

The finding could undercut a leading theory of why sex is necessary. Some biologists say sex is needed to discard the mutations, almost all of them bad, that steadily accumulate on the genome. People inherit half of their genes from each parent, which allows the half left on the cutting room floor to carry away many bad mutations.

More on the Purdue University site here.

Tuesday, March 22, 2005

What is Intelligent Design?

The American Civil Liberties Union, which is fighting the Dover, Pennsylvania, school district over the district's plans to teach intelligent design in its science classes, has put together a nice little FAQ on intelligent design, creationism, and evolution.

Monday, March 21, 2005

Creationists Challenge Evolution on the Biggest Screens

It's not surprising that creationists are threatening to boycott Imax theaters that show educational films that mention evolution. But it's deeply disturbing that the theaters back down to a fight. As the New York Times reports,

Several Imax theaters, including some in science museums, are refusing to show movies that mention the subject - or the Big Bang or the geology of the earth - fearing protests from people who object to films that contradict biblical descriptions of the origin of Earth and its creatures.

The number of theaters rejecting such films is small, people in the industry say - perhaps a dozen or fewer, most in the South. But because only a few dozen Imax theaters routinely show science documentaries, the decisions of a few can have a big impact on a film's bottom line - or a producer's decision to make a documentary in the first place.

Thursday, March 17, 2005

How to Plan a Galapagos Vacation

I've always wondered what kind of vacation packages they offer to the Galapagos Islands for those of us who want to learn a little bit about Darwinism in addition to relaxing at the beach. Here's a great summary. Happy traveling.

Tuesday, March 15, 2005

Charles Darwin: The Power of Place Part 1-Author

Janet Browne begins the second volume of her Darwin biography by describing him as not just a scientist, but as one of the foremost authors of Victorian England. Darwin took his time -- many years -- writing The Origin of Species because he wanted to be sure he got everything correct. Darwin was devastated, though, when Alfred Russel Wallace appeared to beat him to the theory of evolution by natural selection. It's important to remember that Darwinism wasn't a new discovery so much as an improvement upon those who came before him. Wallace was a perfect English gentleman, though, when Darwin told him of his own ideas, writing to a mutual friend that he was glad to know of Darwin's "much earlier and I doubt not much more complete views of the same subject."

As many words as Darwin the author wrote, he's probably best known for words he didn't write. He didn't call his theory "evolution" because at the time the word was used to mean the development of one organism, like an embryo becoming a man. And he chose "descent with modification" rather than "survival of the fittest," a somewhat inaccurate term that was coined in 1864 by Herbert Spencer.

As Darwin prepared to step forward publicly with his theories, he sent The Origin of Species to several respected scientists. Many immediately hailed it as a brilliant work, but some thought Darwin a fool to even consider such a thing. Whitwell Elwin called Darwin's work a "wild and foolish piece of imagination." He thought Darwin would be better off writing a bit about the pigeons he had studied and discarding everything else.

When Darwin finally was prepared to publish, he settled on the title of "On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life." And alongside the title would appear the name Charles Darwin. Many authors of the era -- especially authors who clashed so markedly with established Christian doctrine -- chose to publish anonymously. Darwin wanted to show that he was prepared for an open debate.

Darwin came along at the perfect time to change the world as an author (he and Dickens were contemporaries) because, as Browne writes, "Darwin and his theories -- and then the Darwinian movement as a whole -- benefited enormously from the unprecedented surge in publishing activity in the middle decades of the nineteenth century." As another time, Darwin would not have received the attention that his theory needed to grow.

As Part 1 concludes, Darwin is widely ridiculed for his belief that man and apes were related. What's surprising is how Darwin's critics were completely devoid of any rational argument. The scientist Richard Owen was one of the world's foremost experts on the gorilla, but he'll always be remembered more for his stubborn refusal to acknowledge the similarities between the human brain and the gorilla brain. Owen claimed that God gave humans a hippocampus minor and that it separated humans from gorillas. Of course, gorillas have a hippocampus minor as well, and Owen simply ignored all the evidence in front of him because it offended his preconceived ideas. Some things never changed.

See also my reviews of the first, second, and third parts of the first volume of Browne's Darwin biography.

Monday, March 14, 2005

Battle Lines Drawn in 19 States

A front-page Washington Post story on the battle to teach evolution in public schools has an interesting quote from U.S. Senator Rick Santorum:
"Anyone who expresses anything other than the dominant worldview is shunned and booted from the academy," Santorum said in an interview. "My reading of the science is there's a legitimate debate. My feeling is let the debate be had."

On the one hand, it's depressing that a senator from Pennsylvania -- hardly the Bible Belt -- would say something like that. On the other hand, I do feel somewhat heartened by the fact that people like Santorum and President Bush seem to be giving up on supporting creationism completely and instead are moving in the direction of framing evolution and intelligent design as two competing scientific views. That's not much progress, but it is some.

What bothers me about this article, though, is that it gives ample space to the opponents of evolution without quoting any scientists who could point out that not a single shred of scientific evidence exists for the viewpoint that these people spout.

Tuesday, March 08, 2005

New Bones Give Clues to Human Evolution

Why did our ancestors stop moving around on four limbs in the trees and start moving around on two limbs on the ground? This article suggests that 4 million-year-old bones recently found in Ethiopia could provide some clue.
They include a complete tibia from the lower part of the leg, parts of a thighbone, ribs, vertebrae, a collarbone, pelvis and a complete shoulder blade, or scapula.

The fossils also included an anklebone which, with the tibia, proved that the creature walked upright, said Bruce Latimer, director of the Cleveland Museum of Natural History, Ohio, who led the two-month excavation.

'Right now we can say this is the world's oldest bipedal (two-footed) apeman. What makes us human is walking upright,' Latimer said. 'This discovery will give us a picture of how walking upright occurred. It's a once-in-a-lifetime find.'

Monday, March 07, 2005

Charles Darwin: Voyaging Part 3-Naturalist

The third and final part of Charles Darwin: Voyaging shows the human side of Darwin as he makes a name for himself after returning from the Beagle: Darwin the husband (he married his cousin Emma first, fell in love with her later), Darwin the father (newborn William's instincts fascinated him; oldest daughter Anne's death broke his heart), Darwin the snuff addict.

Darwin and Emma had 10 children, seven of whom survived to adulthood. Leonard Darwin was the last survivor of the brood, dying in 1943. Among Darwin's surviving descendents is the British physiologist Richard Darwin Keynes.

Richard Dawkins has famously said that Darwin allows people to be intellectually fulfilled atheists. But Darwin didn't always feel fulfilled. He struggled with his growing sense that natural selection, and not God, made man and all the creatures of earth. Ultimately Darwin felt that he couldn't tell the religious Emma the truth about his doubts of the existence of God.

But most importantly the third part of Voyaging shows Darwin the tireless researcher. "This moment more than any other in Darwin's life deserves to be called a turning point," author Janet Browne writes of Darwin's discussions with zoologists and geologists when he arrived home from the Beagle's voyage. When a zoologist pointed out to him that a rhea he had collected was a distinct species, he started to wonder why different animals would inhabit nearly identical places, and why extinct animals seemed to be connected chronologically to modern species.

Malthusian economics -- the belief that populations will always increase faster than food supplies and that, therefore, certain groups will not be able to provide for themselves -- weighed heavily on Darwin's mind and helped him craft the idea that scarce resources led to only the best-adapted individuals having offspring.

As Darwin finished his species essay he was so confident that he was on to something great that he left explicit instructions to Emma on how to proceed should he die before it was published.

But Darwin was devastated when, before he could publish his ideas about transmutation, someone beat him to it. In October of 1844, an anonymous author (posthumously identified as Robert Chambers) published Vestiges of the Natural History of Creation. It caused a stir everywhere, but especially with Darwin, who thought he had lost his chance to make a breakthrough. Fortunately, Chambers made several errors that Darwin could correct, giving him, when he finished, the superior work.

It would be a long time before he finished, though. Instead of immediately publishing his counter-argument to Vestiges, Darwin took his time and studied barnacles. Those tiny crustaceans that attached themselves to ships and therefore spread throughout the world helped Darwin to see how species spread and would prove invaluable to him. As the book concludes, Darwin's studying of barnacles has led him to the brink of publishing The Origin of Species. We'll pick up with Volume 2 of Browne's biography later.

Thursday, March 03, 2005

Charles Darwin: Voyaging Part 2-Traveler

Part Two of Charles Darwin: Voyaging focuses on his five years aboard the HMS Beagle. Darwin set sail in December of 1831 and returned in October of 1836.

Janet Browne curiously makes Darwin's month in the Galapagos Islands just one stop along an eventful journey, rather than the most important month of his life, as so many others have portrayed it. Perhaps this is because Darwin's time at Galapagos didn't become important until he returned home and began to study what he had seen there.

For a person of his time and place (an English aristocrat in the early 19th Century) Darwin had a fairly liberal view toward the lower classes. Although he called them savages, Darwin viewed the natives in South America more or less as human beings who deserved the same rights as he did. And he vehemently opposed slavery, although he didn't think to make any comparisons between slavery and the servitude that allowed him to live a life of relative luxury. Browne writes, "Slavery inflamed all his most passionately held beliefs about human nature. It was the one social issue guaranteed to upset and annoy him throughout his long life." The biggest argument Darwin had with FitzRoy in their years aboard the Beagle together was about slavery, which FitzRoy didn't see as a problem.

Darwin was deeply saddened when a letter from his sister informed him that the woman he had courted, Fanny Owen, was engaged to marry another man. Odd that Darwin would expect a woman to wait for him for five years while he sails around the world, but those were different times.

As Darwin becomes a traveler in his 20s, we realize how important his childhood collecting and his scholarly reading of Charles Lyell's Principles of Geology were. Brown writes,

He was convinced that the majestic story of nature could be explained by the accumulation of little things. Though clear enough to him through Lyell's writings, this notion was given physical reality by Darwin's geological researches in Chile and became the hub of all his later biological thinking.

Here's my post of Part 1.

Wednesday, March 02, 2005

Keep Creationism Out of Science Class

An interesting piece written by a high school student who lives in a county where the school board says evolution and creation each deserve a place in science class. The writer is homeschooled and therefore unaffected by the school policy, but it's still worth a read.

Tuesday, March 01, 2005

The Scopes Trial

What most people know (or think they know) about the Scopes Monkey Trial is confined to what they saw in "Inherit the Wind." Which is odd because the authors of "Inherit the Wind" went out of their way to make clear they were writing a work of dramatic ficiton, not a history of an actual event.

If you're interested in learning the truth about the Scopes trial, the best place is Edward Larson's 1997 book, Summer for the Gods: The Scopes Trial and America's Continuing Debate Over Science and Religion. I can't recommend it highly enough.

A good Q&A with Larson from Christianity Today is here. Another good Q&A from Amazon.com is here.

Are Liberals the Greater Threat to Evolution?

Interesting. There's no doubt that the most strident opponents of teaching evolution in America are conservatives. And most of us who strongly support the teaching of evolutoin are liberals. But as Joe Kaplinsky writes, perhaps it's the liberal idea that every viewpoint deserves an equal airing that really causes problems.
But even on a seemingly clear-cut issue such as creationism, the division is not so sharp. Liberals have often been at the forefront of questioning the authority of science. It is liberals who have argued that science education should respect cultural differences and that the curriculum should be immediately relevant to everyday life of students. Creationists have leapt at the opportunity presented by educational theories to put the knowledge of pupils on the same level as that as scientists, by putting forward the demand to 'teach the controversy'.

One thing that intelligent design proponents love to do is put forward equations that attempt to show mathematically how the odds are impossibly high against humans evolving from single-celled organisms. Kaplinksky points out that William Dembski's mathematical symbols "are arranged on the page to bamboozle non-scientists, not to express a chain of logical reasoning."

National Academies and Evolution

I searched for information on evolution on the Web site of the National Academies, and the latest thing I could find was from 2002. Why isn't the National Academies updating its evolution site? Is it bowing to political pressure?