The Surprising Origins of Evolutionary Complexity

Scientists are exploring how organisms can evolve elaborate structures without Darwinian selection

David Speijer, a biochemist at the University of Amsterdam, thinks that Gray and his colleagues have done biology a service with the idea of constructive neutral evolution, especially by challenging the notion that all complexity must be adaptive.But Speijer worries they may be pushing their argument too hard in some cases. On one hand, he thinks that the fungus pumps are a good example of constructive neutral evolution. “Everybody in their right mind would totally agree with it,” he says. In other cases, such as RNA editing, scientists should not, in his view, dismiss the possibility that natural selection was at work, even if the complexity seems useless.

Gray, McShea and Brandon acknowledge the important role of natural selection in the rise of the complexity that surrounds us, from the biochemistry that builds a feather to the photosynthetic factories inside the leaves of trees. Yet they hope their research will coax other biologists to think beyond natural selection and to see the possibility that random mutation can fuel the evolution of complexity on its own. “We don't dismiss adaptation at all as part of that,” Gray says. “We just don't think it explains everything.”

This article was produced in collaboration with Quanta Magazine, an editorially independent division of


Biology's First Law: The Tendency for Diversity and Complexity to Increase in Evolutionary Systems. Daniel W. McShea and Robert N. Brandon. University of Chicago Press, 2010.

How a Neutral Evolutionary Ratchet Can Build Cellular Complexity. Julius Lukeš et al. in IUBMB Life, Vol. 63, No. 7, pages 528-537; July 2011.

This article and more information about Quanta Magazine are available at


This article was originally published with the title "The Surprising Origins of Life's Complexity."

or subscribe to access other articles from the August 2013 publication.
Digital Issue $5.99
Digital Issue + Subscription $39.99 Subscribe
Share this Article:


You must sign in or register as a member to submit a comment.

Email this Article