Darwinian evolution means different things to different people. To me, and many other population geneticists, it refers to positive selection. To Jeffrey Schwartz, an anthropologist at the University of Pittsburgh, Darwinian evolution means gradual change. By the way, Schwartz also thinks humans are more closely related to orangutans than they are to chimps and gorillas.
I’m having a hard time making heads or tails of Schwartz. He seems hypercritical of all molecular evolution — to the point where one wonders whether he even understands the field. He appears to not understand that evolution at different levels (DNA sequence, protein sequence, cellular, anatomical, etc) can occur at different modes and tempos. Many DNA mutations are neutral — they confer no phenotypic effect and no fitness benefit or cost — and these changes are remarkably useful for inferring evolutionary relationships. When looking over short time scales (millions of years), DNA sequences can be used reconstruct phylogenies because they evolve quite rapidly. But protein sequences are more useful over longer time scales (tens to hundreds of millions of years) because they evolve slower.
Furthermore, when one looks at different time scales, the gradual nature of evolutionary change manifests itself at different evolutionary levels. One would struggle to find evidence that amino acid sequences evolve gradually within a species or between closely related species. There simply aren’t enough changes over this short time scale, and when we do see a lot of changes they are examples of evolutionary bursts. But DNA sequences do evolve gradually at this time scale. Schwartz seems to not understand these important points.