Evolution, the concept that each type of animal arose from some other sort of animal, faces many daunting challenges. Among the more difficult hurdles for evolution to clear is the formation of turtles from non-turtles, and the development of snakes from non-snakes. Darwin was fascinated by them both, and openly wondered what path they took on their evolutionary journey.

by Brian Thomas, M.S. and Frank Sherwin, M.A.*

Imagine going to a doctor with a flare-up of gout or a migraine. To your utter shock, the physician calmly instructs you to reach into a water tank and hug an electric fish. This is what Roman physician Scribonius Largus prescribed in his Compositiones Medicae in 46 AD, and it worked too well, probably killing the patient.

Why do men have beards and women do not? Deep in the brain, the hypothalamus produces surges of gonadotropin-releasing hormone, a small chemical that acts like a key to turn on the manufacture and export of follicle-stimulating hormone and leutenizing hormone (LH) from the pituitary gland.