An illustration of Tiktaalik, a famous fossil from the Devonian period, the time of the transition to land. (Image by Zina Deretsky, National Science Foundation (Courtesy: National Science Foundation), via Wikimedia Commons)

When two become one: the evolution and development of external genitalia on land

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.

The bottom skull is from a wolf, Canis lupis, and the top skull is from a Chihuahua. Dogs are a powerful example of domestication-- one which we're still figuring out. (Image by Mccabe via Wikimedia.)

Man’s best friend– since when?

The dog is the only large carnivore that has been fully domesticated and one the few domesticated animals that was not kept primarily for food. Despite their widespread adoption into human cultures today, relatively little is known about the early events in the history of dog domestication. When and where did dogs originally become domesticated? Russ Corbett-Detig explains.

This banana flower (Musa sp.) is just one example of the hyperdiverse Zingiberales flowers. How can flowers evolve to be so different and yet keep the same conserved developmental programs? (Image by Thelmadatter via Wikimedia Commons)

That’s Bananas!—How flowers get fancier

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.