The First Genital In An Animal Evolved From An Extra Pair Of Legs

A recent analysis of placoderm fossils — an early jawed vertebrate — shows that the animal kingdom's first genital organ was a "clasper" that evolved from an extra set of legs, and that the first sexual mating position was likely to have been a missionary one. » 6/10/14 9:40am 6/10/14 9:40am

Sex evolved to prevent parasite infections, say scientists

Sexual reproduction that involves two partners is far less efficient than self-fertilization — at least, from the perspective of evolution. So why did creatures like humans ever start having sex with each other? According to a new study, we did it to fight parasites. We spoke with the researchers to discover what… » 7/07/11 11:18am 7/07/11 11:18am