Books Do Furnish a Life: Reading and Writing Science

by Richard Dawkins

A well-adapted animal reflects, in minute detail even down to the biochemical, the environments in which its ancestors survived. A gene pool is carved and whittled through generations of ancestral natural selection to fit that environment. In theory a knowledgeable zoologist, presented with the complete transcript of a genome, should be able to reconstruct the environmental circumstances that did the carving.fn2 In this sense the DNA is a coded description of ancestral environments, a ‘genetic book of the dead’. The extinction of a species therefore diminishes us in a sense that the death of an individual perhaps does not. To be sure, every individual is unique, and to that extent irreplaceable. But the set of genes in a species’ gene pool represents a unique solution to the problem of survival. An individual organism, by contrast, is only a permutation of the units of that solution: unique, but not unique in an interesting way. If an individual dies, there are lots more where it came from. It is just another deal from the same pack of cards. When the last individual of a species dies, the whole pack has been destroyed.