External genitalia are an important adaptation to life on the land, where eggs may dry out and there is no water for sperm to swim through. Reptiles, birds, and mammals have extremely diverse external genitalia, but they share a common evolutionary and developmental origin. Mara Laslo explains how comparative developmental studies are shedding insight on the development of these remarkable organs.
Frivolous as it may sound to us, making pretty flowers is serious business for a plant. Fancier flowers often mean more attention from pollinators and greater reproductive success, and the huge diversity of flowers around today shows that the evolution of new flower types has paid off. But how can plants afford to experiment with such an important developmental process? As Becky Povilus explains, they do and they don’t.