Much of the physical evidence for evolution comes from paleontology. Before the arrival of molecular genetics, fossils were just about the only evidence available that evolution had actually taken place, and some individual specimens have come to have iconic status for their role in confirming predictions of evolutionary theory (Archaeopteryx, Lucy, Tiktaalik, etc.) (Fig. 43.1 and Plate XXXIII). Darwin, of course, was very much interested in the fossil record, and indeed his geological and paleontological observations both during his Beagle voyage and afterward played a formative role in shaping his ideas about evolution (see Brinkman, Essay 4 in this volume). However, Darwin also worried a great deal about how the fossil evidence supported his theory of evolution; in Origin, he set aside an entire chapter to discuss the “imperfections” of the geological record, and in general it is fair to say he regarded the fossil record as a disappointment at best and a serious liability at worst. Darwin’s assessment of the fossil record, then, cast a long shadow over the subsequent development of the professional discipline of paleontology.

Up until the time of the modern evolutionary synthesis in the 1940s, paleontology was generally regarded by biologists as a discipline suited mostly to the collection and description of empirical evidence – fossils – but not one that could make unique contributions to our understanding of the patterns and processes of evolution. In the mid-twentieth century, however, some paleontologists began to resist this “descriptive” label for their discipline and to promote an approach to the history of life and the fossil record that was explicitly theoretical and evolutionary. By the 1970s, this approach came to be known as “paleobiology,” and today it is one of the central viewpoints in the discipline.