It has been argued that dinosaurs did not die out, but just evolved wings and flew away. At a certain level, this reasoning is sound.... Birds, as a group, did descend from dinosaurs and ... all 8,600 species of birds living today carry some inheritance from their reptilian ancestors.
David M. RaupWe now have a quarter of a million fossil species, but the situation hasn't changed much... We have even fewer examples of evolutionary transition than we had in Darwin's time.
David M. RaupThe charge that the construction of the geologic scale involves circularity has a certain amount of validity. ...Thus, the procedure is far from ideal and the geologic ranges are constantly being revised (usually extended) as new occurrences are found.
David M. RaupThere are millions of different species of animals and plants on earth--possibly as many as forty million. But somewhere between five and fifty BILLION species have existed at one time or another. Thus, only about one in a thousand species is still alive--a truly lousy survival record: 99.9 percent failure!
David M. RaupA large number of well-trained scientists outside of evolutionary biology and paleontology have unfortunately gotten the idea that the fossil record is far more Darwinian than it is. This probably comes from the oversimplification inevitable in secondary sources: low-level textbooks semipopular articles, and so on. Also, there is probably some wishful thinking involved. In the years after Darwin, his advocates hoped to find predictable progressions. In general. these have not been found-yet the optimism has died hard and some pure fantasy has crept into textbooks.
David M. RaupNow let me step back from the problem and very generally discuss natural selection and what we know about it. I think it is safe to say that we know for sure that natural selection, as a process, does work. There is a mountain of experimental and observational evidence, much of it predating genetics, which shows that natural selection as a biological process works.
David M. Raup