If everything when it occupies an equal space is at rest, and if that which is in locomotion is always occupying such a space at any moment, the flying arrow is therefore motionless

26.jpg

For a couple years now I’ve been fascinated by some recent ideas about how complexity evolves. Darwin’s great insight was recognizing how natural selection could create complex traits. All that was needed was a series of intermediates that raised the reproductive success of organisms. But recently some researchers have developed ideas in which natural selection doesn’t play such a central role.

One idea, laid out in the book Biology’s First Law, holds that life has a built-in propensity to get more complex–even in the absence of natural selection. According to another idea, called constructive neutral evolution, mutations can change simple structures into more complex ones even if those mutations don’t provide an advantage. The scientists who are championing these ideas don’t see them as refuting natural selection, but, rather, complementing it, and enriching our understanding of how evolution works.

{ Carl Zimmer | Continue reading | More: Scientists are exploring how organisms can evolve elaborate structures without Darwinian selection }