There are two major reasons that scientists accept common descent as fact. The first is that it is supported by, and accounts for, a multitude of independent observations, including data from genetics, developmental biology, the fossil record, comparative anatomy, and the geographical distribution of species. The second is that not a single observation or inference made over the past 150 years has provided convincing evidence that modern species are not descended from common ancestors. The notion of common descent has even withstood the rise of entirely new scientific disciplines, including molecular genetics and, most recently, comparisons of entire genomes. — T. Ryan Gregory, Darwin’s two-for-one deal