Bighorn sheep. Photo by Noah Reid, via Nothing in Biology Makes Sense.

This week at the collaborative blog Nothing in Biology Makes Sense!, Noah Reid returns to discuss the bane of small, isolated populations: inbreeding depression:

Iconic North American species such as grizzly bears, red-cockaded woodpeckers, and the American burying beetle today inhabit only small fractions of the ranges they occupied only 100 years ago. A result of this fragmentation is that many individuals exist in small, isolated populations. In these populations, a curious phenomenon often emerges, one that can only be understood in light of some basic evolutionary theory.

To find out more about that phenomenon, and when it can become hazardous to a population’s health, go read the whole thing. ◼