Slate takes a break from endless political analysis to tackle a biological question: Can humans have sex with other animals and produce offspring? The answer: "Probably not." Um, "probably"? Oh dear.

When two organisms typically do not interbreed with one another, they are considered different species. But what are the reproductive barriers that isolate one population from another? Hear the ...

"A new species develops if a population which has become geographically isolated from its parental species acquires during this period of isolation characters which promote or guarantee reproductive ...

How species form and what keeps them distinct from each other, even though they can interbreed, is a key question in evolution. Researchers have recently identified genes in three closely related ...

Plants or animals using color to attract a mate is fairly common in nature, but for Phlox drummondii, a wildflower commonly known as Drummond's phlox, just the opposite is true. The flowers, which are ...