Dawn of the deed. Prehistoric Origins of Sex

We all know about the birds and the bees, but what about the ancient placoderm fishes and the dinosaurs? The history of sex is as old as life itself—and as complicated and mysterious. And despite centuries of study there is always more to know. In 2008, paleontologist John A. Long and a team of researchers revealed their discovery of a placoderm fish fossil, known as “the mother fish,” which at 380 million years old revealed the oldest vertebrate embryo—the earliest known example of internal fertilization. As Long explains, this find led to the reexamination of countless fish fossils and the discovery of previously undetected embryos. As a result, placoderms are now considered to be the first species to have had intimate sexual reproduction or sex as we know it—sort of.