Almost all species use sex to reproduce, but biologists struggle to understand why; join Professor Lindsay Turnbull from the University of Oxford as she explains the costs and benefits Sex puzzles biologists because it has a profound cost. Asexual species can potentially grow their populations much faster and so should outcompete their sexual cousins. But sexual species also produce genetically variable offspring - and in a changing environment, this can help them to stay ahead.

Sex also allows individuals within the same species to exchange genetic information, but they can't do this with members of other species. This genetic isolation allows species to follow separate evolutionary paths. These paths can be retraced by biologists using genome sequencing to build a tree of life.

Timestamps:

00:00 Intro

00:16 Titles

00:21 What exactly is sex?

02:22 Fertilisation explained

03:54 Sex in brief - recap

04:21 The problem - The Cost of Sex

05:42 So what is the point of sex?

08:15 How does sex create different species

10:30 Outro