Why Evolution is True

PUBLISHED : Sunday, 22 March, 2009, 12:00am
UPDATED : Sunday, 22 March, 2009, 12:00am

Why Evolution is True

by Jerry Coyne

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It may be referred to as the 'theory' of evolution, but as this excellent science primer makes clear, evolution is more than a theory - it is a proven fact.

In science, the word 'theory' is used slightly differently than it is in everyday conservation. A scientific theory has been vigorously tested and all the objections to it have been judged to be unfounded. It's a fact. We still refer to Newton's theory of gravity, for instance, but none of us would dispute that gravity is real.

Why is this important? Because creationists and their insidious brethren, the intelligent design movement, use the word theory to discredit evolution. They say if evolution is just a theory, it hasn't been proved. The aim of Why Evolution is True, written by evolutionary geneticist Jerry Coyne, is to make clear to the general reader that evolution is a scientific fact as proven as gravity. Its mission is to inform the reader in an easy-to-understand way how evolution has been proved.

It is somewhat worrying, Coyne admits, that such a book should be necessary a full 150 years after Charles Darwin wrote On the Origin of Species. But intelligent design - which is creationism by another name - is growing in the US and Britain. Coyne hopes his book will provide rational people with the information they need to defeat creationists in a debate.

The book is arranged logically. First Coyne explains the theory of evolution. Then he explains the many different methods scientists have used to prove it. Occasionally he attacks the creationists' position and shows how their arguments evaporate in the face of hard scientific facts. But the book is no Richard Dawkins-style attack on religious belief. Many Christians have made evolution compatible with their faith, and many scientists are Christians. Coyne draws a distinction between creationists and those with a more moderate view of their faith.

Even those familiar with the gist of Darwin's theory will be amazed at the elegance and fundamental simplicity of the details. Here's how Coyne describes modern evolutionary theory in one, 'albeit long', as he puts it, sentence: 'Life on earth evolved gradually beginning with one primitive species - perhaps a self-replicating molecule - that lived more than 3.5 billion years ago; it then branched out over time, throwing off many new and diverse species; and the mechanism for most (but not all) of evolutionary change is natural selection.' He then offers a clear explanation of the process of natural selection - the way species adapt to their habitats by mutation.

The proofs take up the bulk of the book. The fossil record provides evidence of the way species have mutated over time. 'Palaeontologists have worked tirelessly to piece together the tangible historical evidence for evolution; the fossil record,' Coyne writes. They have succeeded in establishing a fossil record for many species and this proves that evolution has taken place.

There are different proofs for evolution too. Finding physical remnants of ancient creatures in the physiology of younger species is one, analysing the geographical groupings of certain species is another. DNA testing has given evolutionary biologists many new tools.

Christian creationism largely stems from the US. With a new president in the White House many feel the neo-conservative-led war on science is over. We can only hope the defenders of science and reason will reassert themselves. But Coyne's book rises far above the political. It provokes a sense of wonder at the fact that, if our evolutionary lineage could be traced back far enough, we would find we are at some level related to all living things.