Speeding our way to extinction

It's a rare species that isn't extinct. According to current thinking, there may be more than 50 million species living on Earth at the moment. But they are only a small fraction of all the species that have ever lived. At the University of East London, where Michael Boulter is Professor of Paleobiology, he and his colleague Dilshat Hewzulla have calculated that more than a billion species have come and gone on this planet over the past 3,500 million years.

Boulter and his colleagues work by gathering data about fossils over the internet, and analysing it to see the patterns that emerge. Among different groups of species, diversity seems to rise and fall in similar ways. The graphs look like the signatures of what are known as "self-organising systems". A pile of sand is self-organising too. It grows as grains are added, then reorganises itself in a series of avalanches. In the fossil record, the writing is on the wall. It's a matter of when, and how. Some people worry about asteroids, like the one which seems to have finished off the dinosaurs. Others, including Boulter, fear that humans will prove just as devastating to their fellow species as any asteroid could be.

Some of the evidence against homo sapiens is already in. Humans arrive, in North America, Australia, or Madagascar; large mammals disappear.

Although the idea is still controversial that humans were responsible for the extinctions, palaeontologists are coming to accept that the fossil record shows a smoking gun. Boulter is on shakier ground, though, when it comes to the Neanderthals. His contrast between the "more peaceful" Neanderthals and the "more selfish" modern humans belongs to William Golding's wonderful novel The Inheritors, not to science. And why he thinks that modern humans suddenly invented language, after making art for 10,000 years, is difficult to fathom.

Unfortunately, this isn't the only point that is hard to follow.

Although the book's tone is pleasant and unpretentious, its message is often obscure, and sometimes garbled. The worst problem area is that of his second big "E", evolution. "I must admit to having had trouble for years understanding Darwin's concept of 'natural selection'," he writes, and it's tempting to feel that the struggle is still going on. Readers will certainly have trouble with the concept if they rely on his account. He writes, for example, that Richard Dawkins "believes that all that genes want is to be passed on to the next generation where they will have the best effect". The point of "selfish gene" thinking is that genes just want to replicate themselves, period. They aren't interested in the pursuit of excellence.

Boulter presents the idea of self-organised systems as an alternative to natural selection as a way of explaining evolution - but what is going on in these systems, if not natural selection? He shakes his head at the overoptimistic faith in altruism which he imputes to sociobiologists, apparently unaware that they share his own belief that we are only really interested in ourselves and our close families. Forty years of sociobiological theory is founded on the principle that altruism has to be based on shared genes.

Most modern Darwinists would agree that it's not in our nature to save our fellow species. If we want to, we will have to rise above our immediate selfish interests. For Boulter, though, the bottom line is that we can't beat the self-organising system. His spreadsheets show that the mammals are on the way out, fast. We have started the avalanches, and they will bury us too. If, that is, we really are nothing but mammals.