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A Few Words About Evolution
editorial by David M. Switzer
Next time you're in the mood for some dinosaurs, instead of watching Jurassic Park again check out the BBC's Walking With Dinosaurs. It's a series of half-hour episodes done in the style of a documentary, with each episode focusing on a particular dinosaur. Using the latest research and a combination of CGI and animatronics, it's intellectually and visually stimulating. (You'll also want to watch Walking With Prehistoric Beasts and Walking With Cavemen.)
Of course, we continue to learn new things about dinosaurs. For example, when I was a kid one of the dinosaurs we learned about was brontosaurus. But brontosaurus didn't actually exist -- the person who discovered it put the skull of one dinosaur with the body of another.
Recently fossils of feathered dinosaurs were found in China -- I saw an exhibit about them at the Royal Ontario Museum in Toronto. Studying these fossils will help us figure out the link between dinosaurs and birds. One difficulty with establishing the timeline is that at various times throughout history there have been flightless creatures with wings; at first glance it might seem like a flightless creature is an ancestor of a creature that can fly, but that's not always the case.
One of my favourite books I read last year is Evolution by Stephen Baxter. It's a novel that starts in the time of the dinosaurs and progresses to the present and into the far future. Each section focuses on a particular species of mammal. In the hands of a lesser writer this would be boring, but in Baxter's it's absolutely fascinating. One of the things he points out is that there are many species that existed for which we have no evidence, and will never have any evidence, because they didn't leave any fossils. He fills in some of the gaps with intriguing speculation.
For example, Baxter invents an air whale -- a huge but very light creature that flies above most of the clouds, in the stratosphere. The air whale evolved from pterosaurs, getting lighter and lighter. Its bones are hollow, and it doesn't need a big brain since nothing much happens up there. It feeds on aerial plankton, and mates on the highest mountain peaks when its instincts tell it to. With wings one hundred meters across, it would have been magnificent to see.
Although most of us have come to grips with the fact that Earth isn't at the centre of the universe, we still like to think that humans are at the centre of things on Earth. In other words, we think of evolution as a progression whose end result is us. But although humans are unique in that we are the only creatures who can conceive of evolution, we're "a tiny twig, born just yesterday on an enormously arborescent tree of life that would never produce the same set of branches if regrown from seed" (Stephen Jay Gould, Full House). Our uniqueness as a species is important -- it gives us a certain responsibility. But our nonuniqueness is also important, and should give us a humility and a desire to see our species in the context of a larger whole.
We also need to be careful how we view evolution in the past. From Richard Dawkins in The Ancestor's Tale: "From our human point of view, the emergence of our remote fish ancestors from water to land was a momentous step, an evolutionary rite of passage... That is not the way it was at the time. Those Devonian fish had a living to earn. They were not on a mission to evolve, not on a quest towards a distant future." What causes an evolutionary change? Dawkins suspects that "major new departures in evolution often start... with a piece of lateral thinking by an individual who discovers a new and useful trick, and learns to perfect it. If the habit is then imitated by others, including perhaps the individual's own children, there will be a new selection pressure set up."
The Ancestor's Tale is sometimes a tough read, in terms of its scientific content, but it has lots of interesting things in it. Contrary to Evolution, this book moves backwards in time. Each section talks about the most recent common ancestor (MRCA) for some number of species: for example, the first section is about the MRCA of all humans (thousands to tens of thousands of years ago), and the second section is about the MRCA of humans and chimpanzees (5 to 7 million years ago). By the time we get to the eleventh section, we're meeting up with rabbits (75 million years ago).
Jared Diamond, in The Third Chimpanzee, imagines that "had a visitor from Outer Space come to Earth in Neanderthal times, humans would not have stood out as unique among the world's species. At most, the visitor might have mentioned humans along with beavers, bowerbirds, and army ants as examples of species with curious behavior." One of the mysteries of recent evolutionary history is what Diamond calls the "Great Leap Forward." Prior to this event our ancestors had been making the same sort of simple tools for about a million years. Around 40 000 years ago something incredible happened: human culture became more complex, for the first time creating more specialized tools, artwork, and music, and leaving objects in the graves of their dead. Diamond hypothesizes that this might have come about with the development of language, or more complex language, but no one knows for sure.
Farther back in time, another mystery is why our ancestors started walking on two legs. Farther back than that, another: why did we lose our tail? You have to think about things in a different way when you're thinking on an evolutionary scale. As Dawkins points out, "the odds against a floating mangrove bearing a pregnant female monkey and reaching landfall in any one year may be ten thousand to one against... But given 10 million years it becomes almost inevitable."
Dawkins says that "usually, in order for an ancestral species to split into two daughter species, there is an initial, accidental geographical separation between them." For example, the Rift Valley in Africa may have separated the species that eventually became humans from the species that eventually became chimpanzees.
We all know about the huge extinction, possibly caused by a meterorite or comet hitting Earth, that took place 65 million years ago. But that wasn't the biggest extinction -- the biggest occurred earlier, about a quarter of a billion years ago, when 95 per cent of the species went extinct.
As for the creationism versus evolution debate going on in certain places, a creation myth is an aspect of religion. As such, it's a perfectly valid topic for a religious studies course but has no place in a science course. Here's Michael Shermer on the subject, from Why People Believe Weird Things: "Myths are about the human struggle to deal with the great passages of time and life -- birth, death, marriage, the transitions from childhood to adulthood to old age. They meet a need in the psychological or spiritual nature of humans that has absolutely nothing to do with science. To try to turn a myth into a science, or a science into a myth, is an insult to myths, an insult to religion, and an insult to science. In attempting to do this, creationists have missed the significance, meaning, and sublime nature of myths."
There are, of course, many creation myths from around the world. As Isaac Asimov points out in The Roving Mind, "these Hebrew myths are not inherently more credible than any of the others, but they are our myths and the only ones that the creationists are interested in or (in most cases) have heard of, and the only ones they want to propagate." A friend once took me to hear a creationist speak. It was a very strange experience -- I felt like everyone else in the room was very different from me. I wasn't afraid for my life or anything, but it was eerie. And I was annoyed, because the speaker didn't back up any of his points. But everyone else in the audience was predisposed to agree with him and they thought he was great. He had memorized the Bible, giving him an air of authority. But anyone can memorize the Bible -- that doesn't mean you know anything about anything.
I'm perfectly willing to entertain the notion that God created the world 6000 years ago -- and made it look like the world was created 4 billion years ago. But so what? I don't see that it makes any difference at all.
Dave Switzer is currently trying to decide whether or not to move to a new city, something he hasn't done since 1989. He has become a huge fan of the new Battlestar Galactica series -- his favourite character is Commander Adama. And having watched more of Buffy and Angel since last time, he's decided that his favourite characters are Spike and Cordelia, respectively. Two of his favourite CDs to listen to these days are the soundtracks from Shrek and The Rock. Two superb short story collections he's read recently are Gravity Wells by James Alan Gardner and The Birthday of the World by Ursula K. Le Guin.
Cover artist Quynh Mai Nguyen was born and raised in Saigon, Viet Nam before immigrating to Canada with her family in the mid seventies. In her early teens, Japanese animation or manga greatly influenced her artistic styles. In her early twenties, she experimented with other forms of art medium: oil, acrylics, pastel, pottery and watercolor. However, it was Chinese brush painting that drew her passion and attention. Lingnan brush painting is a departure from the traditional Chinese brush painting styles, in that Lingnan style is bold, vital and full of colors, much like a western oil canvas. Yet Lingnan still retains the traditional and important brush strokes.
Last modified: October 12, 2009
Copyright © 2006 David M. Switzer