National Geographic has a gallery of seven "missing link" species whose fossils have been discovered since Darwin proposed the origin of new species by means of natural selection. It troubled Darwin that the fossil record didn't show more explicitly the transitions between species, but he proposed his hypothesis anyhow. Good hypotheses make testable predictions, and this is a nice example of how the ensuing 150 years of paleontology have validated the notion of species' change through time.

Labels: art, evolution