Evolution 101 Common Ancestor
The Evolution 101 Common Ancestor website, produced by the University of California, argues that “the central idea of biological evolution is that all life on Earth shares a common ancestor.” This idea dates back to Charles Darwin’s grandfather, Erasmus Darwin (1731-1802). He proposed that “all warm-blooded animals have arisen from one living filament,” which is a common ancestor.
In their book Tree Thinking (2013), David Baum of the University of Wisconsin, along with Stacy Smith of the University of Colorado, attempts to build on this Darwinian argument. “This means,” they argue, “that evidence of common ancestry is also evidence for evolution.” Scientific evidence for this argument for natural selection, however, is sketchy at best. As Baum and Smith explain, “tree thinking is conceptually challenging” since tracing a species back to a specific common ancestral species remains, as this article will demonstrate, more theoretical than factual.
