Review: PBS's Evolution

Review of Episode One

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Darwin's Dangerous IdeaPBS began a seven part series on evolution this past week. It was produced by WGBH here in Boston (well, not here, but not that far away, either). I've just viewed the first installment titled Darwin's Dangerous Idea. (A sidebar - I'm recording the entire series on my TiVo, a digital VCR that makes recording unbelievably simple. Earlier this year I told it to record anything about evolution, and it's recording the series automatically.)This episode blends drama and documentary. The drama is bad, and I won't comment on it much. The acting was uniformly poor, as befits a PBS series, with the remarkable exception of Darwin's brother Erasmus, played by Mark Tandy. It was difficult to bear each appearance of daughter Annie on the screen since I knew what would happen, and the effect her death would have on Darwin. He carried the despair of this tragic event though his entire life.Illustration of the development of Darwin's ideas through dialogue was a failure, and I'll just give one example. The inspiration Darwin derived from a reading of Malthus is presented on screen as Darwin picking up the book in a sitting room and reading the frontispiece while his brother Erasmus gives a two sentence summary. Darwin immediately replies that this is the crucial connection he needs, and Erasmus declares Darwin's theory complete. What hogwash!The drama is interspersed with documentary. For those of us already familiar with evolution there was nothing new, but it was a powerful statement of why evolution is so widely accepted. The evolution of the eye often comes up in the Creation/evolution debate, and Dan-Eric Nilsson (a hyphenated first name?) of the University of Lund in Sweden has studied the evolution of the eye and shown how it could have evolved in only a half million years given known mutation rates. First there's a light sensitive patch, then increasing concavity provides rough directional ability. A narrow opening at the front provides some rough focusing power. A cover to the opening provides protection, and then fluid between different layers provides a rough lens.Professor Nilsson also explains how we know that human and chimp DNA is 98% similar, and this leads into a presentation of Sally Boysen's work (at Ohio State University) on chimp intellectual development. It is often said by Creationists that such uniquely human abilities such as music and art could not have evolved because they are not needed in the wild. But Boysen has discovered chimps can be taught to count, something they didn't evolve in the wild, either. Both humans and chimps have inherent capabilities that seem to spring from nowhere and which are apparently just a side effect of our large brains.Steven Jay Gould of Harvard and Daniel Dennet of Tufts provide continuity and high level explanations of evolution and of Darwin's discovery of it. Kenneth Miller of Brown University, who I think some of us have encountered on message boards from time to time, has written a book called Finding Darwin's God in which he reconciles evolution and religion, and he had what I felt to be the strongest statement bearing on the Creation/evolution debate:

I don't find God in the insufficiency of science to explain things. In other words, I don't find God in ignorance. I don't find God because we say, "Well, we can't explain that, that must be something that God's doing..."

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A long time ago people were sufficiently unknowing of how things worked in the natural world to see when the sun moved across the sky they imagined God had to push the sun across the sky. And gradually we began to realize the world works according to physical laws. Science investigated those laws.

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So what room is there for God in present day life?...He's the guy who made the rules of the game, and he manages to act within those rules.

I like this statement. He says we gradually learned the world works according to physical laws, not according to the actions of a God or gods. Wherever we look, even inside the cells of life, all we find is matter and energy obeying physical laws.--Percy

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[This message has been edited by Percipient, 11-24-2001]

Review of Episode Two

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Great TransformationsThis episode covered the significant transitions in evolutionary history: the first animals and the early emergence of all the body plans in existence today; the evolution of the first tetrapods and first land animals; and the evolution of whales.The broad outline is the same story many of us are already familiar with, but one thing the episode made clear: Talk.Origins may be getting out of date. Much of the evidence presented for whale and tetrapod evolution was unfamiliar to me.I'll comment about just one portion of the program. Jenny Clark of Cambridge works in the area of tetrapod evolution. Several years ago she brought back several tons of fossil bearing rock from Greenland containing evidence that tetrapods evolved limbs before they emerged on land. This contradicted the conventional view that tetrapods gradually evolved limbs only after emerging on land. One possible explanation for the evolution of limbs by an underwater creature was that it provided a temporary means of escape from predators.Creationists may find this episode very informative, not because it will convince them, but because to accurately criticize evolution it helps to be familiar with what it actually says. This episode was a very up-to-date summary of these topics.--Percy

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[This message has been edited by Percipient, 11-24-2001]

Faith wrote:

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All of the theory of evolution is built on such imaginative scenarios...

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Imaginative scenarios about things like tetrapod evolution are not the evidentiary foundation of evolutionary theory. During the first half of the 19th century geologists deduced that evolution had occurred based upon the evidence found in the roadcuts and mines that resulted from the burgeoning industrial revolution. It is the hard evidence of things like fossils and the geological column that enable us to learn enough about evolution to speculate meaningfully about how long ago organisms might have evolved. We may never know whether any particular scenario is correct, so much evidence is lost through time, but that evolution happened is a surety.Nearly all Creationists accept evolution at the species level, but deny the possibility of evolution from an existing kind to a new kind. What reins in change to keep an evolving species from changing to the point where it becomes a new kind is never explained.--Percy

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[This message has been edited by Percipient, 11-24-2001]

Review of Episode Three

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The Evolutionary Arms RaceThe discussion in the previous message from Faith refers to this third episode in the series. Faith's comments are accurate that the kind of evolution described is of a minor nature. The examples are of germs evolving immunity to drugs and of newts evolving greater toxicity as a defense against predators, not of creatures evolving new organs or limbs. But evolution that takes place in real time is limited to tiny steps.Though not mentioned in the episode itself, the evolutionary arms race is the source of the common misunderstanding that evolution is change in the direction of improvement. If one looks at the fossil record one sees a record of increasing sophistication, with modern plants and animals apparently representing the pinacle of evolutionary achievement. Many people conclude, for example, that ancient hominids evolved toward modern humans with direction and purpose. This conclusion is wrong.Evolution is directionless. Creatures evolve only in response to environmental pressures. The hawk didn't evolve great visual acuity simply because that was the future destiny of primitive hawks, but because their prey became increasingly difficult to find from the air. Those hawks most likely to survive and produce offspring were those who could see best. Those prey most adept at hiding were also most likely to survive and produce offspring. Both predator and prey passed on their traits to their offspring who continued the battle right into the present.The same is true of Wile E. Coyote and Roadrunner. This isn't well known, but coyotes and roadrunners used to be pretty slow, carrying out the chase at a walk, and only fast walking coyotes ate dinner. Then some roadrunners evolved the ability to trot, and as this improvement became increasingly dominant among roadrunners more and more coyotes went hungry, until they too evolved the ability to trot. But then some roadrunners evolved the ability to run, and so the coyote also evolved the ability to run. And so today coyotes and roadrunners are pretty fast and a couple actually starred in a successful cartoon series. I don't have an evolutionary explanation for Speedy Gonzoles the mouse , though - he must be a freak mutant.This episode relates the story of the mystery of three hunters found lying dead around their campfire. Foul play was not a possibility, there was no evidence of violence, and the only thing unusual was a dead newt in the coffee pot. This newt, it was found, was incredibly poisonous. In fact, it contained enough toxin to kill a hundred human beings. What possible reason could there be for this newt to evolve such incredible toxicity.It turns out that the primary predator of the newt is the garter snake, which, fortunately for the garter snake, happens to be immune (mostly) to the newt's toxin. Apparently, newt and garter snake have been involved in an evolutionary arms race, where the newt evolves greater toxicity and the garter snake evolves greater immunity to the toxin. The net result is a newt of incredible toxicity, and a snake of incredible immunity to toxicity. The snake apparently does pay a price. The greater its immunity, the less its agility.So we humans aren't intelligent because that was our evolutionary destiny, but only because it was a response to increasing threats from our environment. Perhaps we were competing with other hominid species. Or perhaps with predators. Or perhaps with each other, evolving ever increasing social skills in order to win that desirable mate!--Percy

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[This message has been edited by Percipient (edited 11-18-2001).]

I wrote:

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So we humans aren't intelligent because that was our evolutionary destiny, but only because it was a response to increasing threats from our environment.

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Faith replied:

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The probabilities involved in such a notion are staggering...

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And you were up all night doing the calculations?You can walk coast to coast in tiny steps of only a couple feet. You've already conceded microevolution, now you have only to explain what keeps the tiny steps of microevolution from accumulating into really big changes.

Faith replied:

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Forgive me if I comment that the evolutionists' imaginative explanations for why evolution may have occurred in a particular case, such as human intelligence, are so mean and paltry that if that's what they think life is really all about I'm amazed scientists desire to go on living it.

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I think you may be confusing evidence for evolution with proposed hypothetical scenarios for how evolution might have taken place. We have fossils as way stations through which we know evolution must have proceeded, and we have the final result in ourselves, and we have a bunch of other evidence such as genetic research tracing the maternal origins of mitochondrial DNA and the paternal origins of the Y chromosome, and after that we just do the best we can.But I have a feeling you're not rejecting these scenarios because of any specific deficiencies, but simply because you reject all evolutionary scenarios.Keep in mind that Creationists don't really have a good definition of kind. For all you know, Homo sapiens and Australopithecus afarensis are of the same kind.--Percy