Evolution

A new study shows that early modern humans on the South African coast used fire in toolmaking as long as 72,000 years ago. The work offers evidence that complex cognition in humans developed earlier than scientists previously thought. --by Carol Hughes

Brian Sullivan studies toad toes to understand cross-breeding between two Arizona species. --by Matt Crum

You shouldn't use your teeth to open a beer bottle or crack a nut--you'd break a tooth or even your jaw. But our earliest ancestors could have done it. Super-strong jaws in our 2.5-million-year-old relatives helped them adapt to changes in food sources in their environment. --by Jodi Guyot

Cuatro Cienegas, in Mexico's Chihuahuan desert, might hold the key to secrets about microbial evolution, the Cambrian Explosion, speciation, extraterrestrial life, and just about everything else. That key is phosphorus. --by Margaret Coulombe

The chemical makeup of the oceans has changed dramatically over billions of years. As a result, the ancient oceans are helping us understand how organisms and ecosystems evolve to cope with changing abundances of elements. --by Jenny Green

Why did the earliest life on Earth--mostly bacteria--remain virtually unchanged for a billion years? --by Diane Boudreau