Paleontologies! Perspectives on Morphological Evolution

The fossil record documents over three billion years of evolution. Darwin considered the general succession of morphologies in the fossil record to corroborate the basic idea of evolution by natural selection. However, he also recognized aspects of the fossil record that challenged his ideas. For example, did the sudden appearance of higher taxa reflect a different underlying model of evolution or the imperfections of the fossil record? In the 150 years since the publication of The Origin of Species, paleontologists have used fossil data to challenge, corroborate, and augment elements of Darwin's basic model. Here, I will focus particularly on work from the last 40 years. In that time, paleontologists have taken advantage of advances in biological theory and quantitative methods to predictably and quantitatively summarize patterns that Darwin could only describe verbally and to articulate predictions for Darwin's models that Darwin himself was unable to derive. Paleontologists also have devised tools for assessing sampling levels, thus testing whether geology or biology might be responsible for patterns. Fossil data contradict some of Darwin's ideas, such as the idea that differences among higher taxa reflect the unsampled, long-term accumulation of changes. However, fossil data strongly corroborate Darwin's idea that natural selection is the major force for fixing novelties once they do appear.