Top: The ninespine stickleback, Pungitus pungitus, is typical of the saltwater form. Bottom: A freshwater form of stickleback with fewer bony plates and fewer spines. Image based on drawings from the ...

Parallel evolution is the independent evolution of similar traits, starting from a similar ancestral condition. Frequently this is the situation in more closely related lineages, where several species ...

Forbes contributors publish independent expert analyses and insights. I write about biodiversity and the hidden quirks of the natural world. Evolution is a long, slow and continuous experiment where ...