Lonely at the top.
July 30, 2011 § 8 Comments
Without the book in hand you will have to imagine some of the images described, but imagining is one of the strengths of our species.
In the first picture is Emma Mbua, curator of hominid fossils at the National Museum, Nairobi. Standing beside her is the 1.6 million-year-old skeleton of Turkana Boy.
Emma, with her great cranial capacity, is clearly a member of the current hominid club, Homo sapiens (note her thoughtful expression and the ease with which she stands erect).
I’m afraid that Turkana Boy, with his shallow brain pan and great-apelike lower jaw can only claim membership in the less exclusive Homo erectus club. It is Emma’s kind that invented the cotton gin, slavery, envy, the rubber band. For the tribe of Turkana Boy, the rise off all fours was a big deal.
Turn the page. Here is Wiwaxia corrugata, one of the enigmatic fossil creatures of the Burgess Shale. Among the tiny phantasms, each an experimental model for future life, this inch-long bright idea turned out to be a winner. It is the ancestor of the polychete worms still found in magnificent variety in the earth’s seas.
In this shadowy two inch ribbon worm is the germ of an idea, a structural plan from which whole phyla will arise. By repeating and varying this one idea, the embroidery of evolution will produce a fish, a bird, a cat, a man.
Turn the page. Welcome to the gallery of extinction! Extinction is the background music of evolution, the final quiet notes of species unable to cope with change or the pressure of competition. And it’s not all bad. Extinction makes room for the next worm with a good idea.
Operating on its own, extinction occurs at a fairly stately pace, but there are ways for a clever species (especially one with opposable thumbs) to speed things up.
Bones and beaks displayed on velvet are all that’s left of the giant flightless bird the Moa-Nola. Until recently the demise of the Hawaiian Island biota was blamed on Europeans. Bringing with them their dogs, their sheep, their pigs, the conquerors ate and grazed the native species to death. But it seems that, at least in the case of the Moa-Nola, an even earlier race of man, the aboriginal Polynesians, are responsible.
We have been in the business of extinction for a long long time
Men draw diagrams of evolution. They look like trees. One early model, from William K Gregory’s 1929 book, “Our Face From Fish To Man” places the Devonian shark at the bottom. By gradual but ambitious changes the shark becomes the Roman athlete at the top. A Horatio Alger story scrawled across millennia.
Each evolutionary tree tells a slightly different, speculative story. They agree on just one thing. The story ends with us, always. We are the goal of all that survival-of-the-fittest warfare. We are the crown of creation.
We sit on evolution’s highest branch and lop out branches below us. It’s getting lonely up here.
Our own species will one day lie down in the dust of extinction (no doubt taking most of Earth’s biological life out with us) and like the simple creatures of the Burgess Shale, we will leave a final portrait in stone.
Some upstart worm will begin again, obeying the imperative of life to rise, complicate, multiply. And what will the creature at the top of that tree look like? Probably not like us. Life, like snowflakes, seeks variety.
In some unimaginable museum of the future our bones will make a nice display.