To explain why men are on average taller than women, scientists theorized about competition for mates. But the effects of estrogen on bone growth may be answer enough.
Only 170 million years ago, new plankton evolved. Their demand for carbon and calcium permanently transformed the seas as homes for life.
Researchers agree it’s a long shot, but transmissible cancers could theoretically evolve into independent species. Certain weird parasites might be living proof.
Researchers struggle to incorporate ongoing evolutionary discoveries into an animal classification scheme older than Darwin.