sapiens? movement. THE EVOLUTION of our species, like the evolution of all the other major classes and groups of species we see today, is by and large a product of contingency, of lucky breaks.
This is the central argument that Gould puts in 'Wonderful Life'. It is an argument that shoots right at the heart of the popular notion that evolution is an inherently progressive and ordered process. One that lifts simple life up to more complex forms, and ultimately results in that pinnacle of evolutionary accomplishment - us.
Much of the book is devoted to looking in detail at one particular bunch of fossils from a place called the Burgess Shale in British Columbia. The fossils themselves have been known about for over eighty years now. But it is the interpretation of them that Gould Whites a0011.
Sudden appearance
The Burgess Shale was discovered in 1909 by the then leading palaeontologist and top science administrator, Charles Walcott. The reason for their importance is their age. Modern multicellular animals make a sudden and dramatic appearance in the fossil record in rocks that are some 570 mil lion years old. This period of life is known as the 'Cambrian explosion'.
Within 100 million years - the geological wink of an eye - just about all the major groups of modern animals had evolved. The Burgess fossils come from a period that was just after this explosion, and so provide a window through which we can glimpse this most important of evolutionary events.
Walcott collected and classified Page 10 July 20, 1991 No.6 What would happen if we could zoom 3.5 billion years back and play the tape of evolution again? Would life have evolved in a similar way and inevitably thrown up a self-conscious, tool-manufacturing, language-using primate species like Homo In all probability, no - says palaeontologist and science writer, Stephen Jay Gould in his book, 'Wonderful Life'. SAM INMAN some 12,000 Burgess fossils in his life. Every single one of these he 'shoehorned' into modern groups. Walcott assumed that each type of Burgess animal was a primitive pre-cursor to later, more advanced forms of these groups. He was wrong. Good science The story of how these fossils came to be reinterpreted is a fascinating example of 'good science'. Gould suggests that 'the greatest impediment to scientific innovation is usually a conceptual lock, not a factual lack'. Yet with the Burgess fossils, Gould is mere ly a commentator, albeit a highly informed one. The nuts and bolts of • reclassifying the animals was done by Harry Whittington from Cambridge University and two of his graduate students, Simon Conway Morris and Derek Briggs. The work started in the early 1970s and continues today. Whittington and colleagues did not set out to radically reinterpret the entire history of life. This was the outcome of their work, not the motivation. Nevertheless, radical it certainly turned out to be. About eighty per cent of all known suedes on ine earin tooat are arthropods. Despite our rather egotistical belief that mammals (and particularly human mammals) are the most successru evolutonary invention since the Big Bang, the Arthropoda phylum remains the largest and most ecologically diverse of all. Taxonomists (the people who classify different forms of life have classified around one million species of arthropods. All of these fit into four major groups - the trilobites (extinct CREATONS NEANDERTHAL uniramians (insects). 'ecology outward. occur by' tery. the top of the tree. MODERN MAN Some of the 'weird and wonderfuls' from Burgess Shale today), the crustaceans (crabs, lobsters...), the chelicerates (spiders, scorpions, mites...), and the Squeezed in Representatives of all four major have. groups of arthropods are found give of amongst the Burgess animals. But additional to these are a further twenty or so that can only be classified as different arthropod designs, not represented in today's fauna. Walcott, however, squeezed them all into modern groups when he shouldn't have done.
On top of this, there are further twenty Burgess species which cannot even be placed in known phyla, and should, therefore, be placed in their death. own separate and unique phyla. The traditional view is that phyla have evolved through a process of many speciation events, that accumulate differences over time. The 'discovery' of the twenty odd unique Burgess phyla fundamentally challenges this view.
The process of evolution is often diagrammatically illustrated with trees. Evolutionary trees were intro duced in the 1860s by the German biologist, Ernst Haeckel. In fact the same guy also introduced the word According to the conventional view, shared by everyone from Haeckel to Walcott to many today, evolutionary trees look like big oal rees, that branch ever upward and Lottery What the evidence from the Burgess Shale shows is that evolution does not 'slow, continuous proliferation and advance, but [current patterns of life were] set by a pronounced decimation (after a rapid initial diversification of anatomical designs), probably accomplished with a strong perhaps controlling, component of lotThis turns the oaks into some thing more like a Christmas tree, with maximum diversity at the bottom not So, what do all these Burgess 'weird and wonderfuls' have to do with marxism? In a direct sense, not a lot. But evolutionary theory is, and always has been, an intensely political subject. Be cause it is an historical science, it has rarely been given the same status as so called 'hard' sciences like chemistry or experimental physics. Evolutionary scientists cannot possibly re-run the tape of life again to check their theories. They have to look for patterns in the historical evidence they The picture that the Burgess fossils Revolution can be quite disconcerting for traditional human chauvinists. Life was not one long march of progress towards consciousness. Nor is evolution a comfortably predictable process. Mass extinctions throughout the history of life have profoundly altered the course of evoluion and should give us, as a species, a chilling reminder of the impartiality of Dinosaurs Homo sapiens is a large(ish) animal inhabiting and dominating all parts of the land surface and ecology of this planet. But so did the dinosaurs, and they lasted for a good deal longer than we have to date. The lesson of evolu tionary history is quite simple. It has often been the seemingly successful animals that have disappeared in periods of rapid evolutionary change, often brought on by rapid environmental change.
It would be a dangerous and nisplaced arrogance on our part to as sume it would be different for us. O course, in no way does this mean that we are destined to extinction. Destiny, God (in all its forms), and 'Gaia' have nothing to do with it. There is no morality in nature. Humans have an ace card they can play in the poker game of evolution - their capacity to consciously direct the course of their own future. That's something the dinosaurs never had.
In Wonderful Life', Gould takes the reader on a journey that is both exotic n its imagery and scientific in it: nethod. You don't have to be a biologist to read, enjoy and understand it. Hopefully, after reading it, many more people will have a little more understanding of some of the most exciting and, at the same time, humbling debates in science. Marxists can learn a lot from this approach. As Gould says, of humans, 'we are a thing, an item of history, not an em bodiment of general principles!
PHOTO: John Harris Culture
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