Ravens Are Evolving, and Not in the Way You'd Expect
A new study shows that the common raven is anything but commonplace in its evolution.
Using DNA samples taken from ravens for nearly twenty years, the study provides evidence that common ravens on the western coast of North America have split into three genetically distinct groups. What’s more, two of these lineages appear to be in the process of melding back into one, scientists report Thursday in the journal Nature Communications.
For a long time, we’ve tended to think of the evolution of species as a branching tree, with new species splitting off as their own branches, says Anna Kearns, an evolutionary biologist at the Smithsonian Conservation Biology Institute.
“You see a split and then you see another split, and then you see another split, but you rarely see those two branches that are split come back together again,” says Kearns, who led the new study.
But occasionally, the branches of a family tree do merge back together, and two lineages—or groups that were on their way to becoming separate species—become one. Scientists call this “reticulate evolution,” says Kearns, and it’s been seen in only a handful of other species, including finches and two kinds of fish.