| We are, each of us, a multitude.Sex seems to have been invented around two billion years ago. Before then, new varieties of organisms could arise only from the accumulation of random mutations – the selection of changes, letter by letter, in the genetic instructions. Evolution must have been agonizingly slow. With the invention of sex, two organisms could exchange whole paragraphs, pages and topics of their code, producing new varieties ready for the sieve of selection. Organisms are selected to engage in sex – the ones that find it uninteresting quickly become extinct. And this is true not only of the microbes of two billion years ago. We humans also have a palpable devotion to exchanging segments of today. |
