Life: complexity and diversity- 6. Whither diversity

Abstract

The evolutionary history of life is one of continual expansion, of coming into being of increasingly greater diversity of more complex organisms, colonising ever newer environmental regimes. It is a cosmic drama that has become ever more elaborate, as it retires some, but inducts an even larger number of increasingly sophisticated actors into its fold. But the process has by no means been monotonic. It is as if the stage is cleared from time to time to make for fresh beginnings, with major bouts of extinction. Humans are amongst the most complex products of evolution having in turn populated the world with ever growing numbers of complex artefacts. These artefacts are now threatening to overwhelm the diversity of life. But humans may one day engineer life capable of surviving in outer space, and thereby trigger off a new phase of expansion and diversification of living organisms.