How spiders evolve

Species evolve very very slowly but every now and then there is an event that can speed the process up. One such event is thought to have happened to the spider 400 million years ago.

Alistair McGregor, a professor of evolutionary and developmental biology at Oxford Brookes University, has been studying it and what it might mean both for spiders and for the process of evolution.

(Image: Spider in a web, credit: BBC)