Convergent evolution

Charles Darwin famously concluded On the Origin of Species with a vision of "endless forms most beautiful" continually evolving. More than 150 years later may evolutionary biologists see not endless forms but the same, or very similar, forms evolving repeatedly in many independent species' lineages. A porpoise's fishlike fins, for example, are not inherited from fish ancestors but are independently derived convergent traits. In this book, George McGhee describes the ubiquity of the phenomenon of convergent evolution and connects it directly to the concept of evolutionary constraint--the idea…