Evolution

Some species have the equivalent of many more than two sexes, but most do not. A new model suggests the reason depends on how often they mate.

New results emerging from graph theory prove that the way a population is organized can guarantee the eventual triumph of natural selection — or permanently thwart it.

Elastic springs help tiny animals stay fast and strong. New work is finding what size critters must be to benefit from the springs.

Life needs more than water alone. Recent discoveries suggest that plate tectonics has played a critical role in nourishing life on Earth. The findings carry major consequences for the search for life elsewhere in the universe.

Just as antibiotics have bred resistance in bacteria, vaccines can potentially lose their effectiveness over diseases they controlled. Researchers are working to head off the evolution of new threats.

For the first time, researchers have traced the genetic programs that guide the development of each cell in early embryos. Surprisingly, even cells that start out different can end up the same.

To date the branches on the evolutionary tree of life, researchers are looking at horizontal gene transfers among ancient microorganisms, which once seemed only to muddle the record.

How the ultra-cooperative behavior of ants, bees and other social insects could have evolved continues to challenge formal analysis. But a new theory about hedging bets against nature’s unpredictability may change the math and shift the debate.

For decades, researchers have commonly assumed that higher oxygen levels led to the sudden diversification of animal life 540 million years ago. But one iconoclast argues the opposite: that new animal behaviors raised oxygen levels and remade the environment.