Gills are the equivalent of a mammal’s lungs, says Jeffrey Malison, director of the aquaculture program at University of Wisconsin-Madison. “Their primary purpose is to exchange gases, take oxygen in and release carbon dioxide out of the fish.”
Both lungs and gills have a bed of very small blood vessels with thin walls that the gases [...]

Conventional wisdom says species form faster in the biodiverse tropics. But a new study shows fast speciation and extinction at the poles. Why didn’t we think up this study?

A new study reveals rapid evolution of white-footed mice in Chicago, in just 150 years.