If all animals were created together and most became extinct over several thousand years (or even hundreds of millions of years in old-earth creationism), why don't all animals show up together at the earliest geological level, with the number of species decreasing as time goes on? If creationism were true, this is what we would expect. But instead, the nature of the fossil record supports evolution. Simpler organisms are found at lower levels and more complex ones at higher levels, and different species of animals appear at different times. Furthermore, the total number of species living at any particular time varies. There are numerous peaks and crashes, corresponding to numerous extinction events, both minor and major. After each mass extinction, many new species begin to appear. But if these subsequent animals were specially created at the beginning of earth's history along with all other species, where is the record of their prior existence? It seems that creationists have more serious gaps in their fossil record than evolutionists allegedly do in theirs. - Joyce Arthur, Extinction and the Geological Record.