The text below is something posted often in the comments on the old blog in response to creationists challenging evolution. If you think evolution is false, please try to come up with a compelling explanation other than common descent for the evidence in the natural world. This focuses on one particular line of evidence for evolution, biostratigraphy. As you go up the geologic column, dated both relatively (in relation to younger strata above and older strata below) and absolutely (via hundreds of concordant radiometric dates using a variety of techniques), all over the world, you find the same successional order of appearance.
At the lowest levels you find nothing but bacteria. Even among bacteria there is a specific order, divided into prokaryotes and eukaryotes. That is all there was on the earth for about a billion years. Then the first multicellular life appears in the form of stromatolites and, along with bacteria, are all that there was for over 2 billion years. Then the first metazoic life appears around 600 million years ago, all marine invertebrates. These marine invertebrates become more diversified – trilobites, mollusks, brachiopods, echinoderms, etc, and after 150 million years or so we find jawless fishes, the first vertebrates. Vertebrate fishes become more and more diversified, then the first amphibians appear. Amphibians become more diversified for about 70 million years and then the first reptiles appear. Reptiles become more diversified over the course of about 80 million years and then the first mammals appear in very limited niches. Then the first birds begin to appear after another 70 million years or so. Reptiles dominate throughout this period, especially dinosaurs, and then 65 million years ago they become extinct. After that, mammals suddenly begin to diversify and appear in greater numbers and greater variety. 10 million years later, the first primates appear. Then the first marine mammals.
This order of appearance is the same all over the world no matter where you look. And within each of these groups, you find an equally interesting order. The first amphibians to appear are nearly identical to the shallow marine fish they are thought to have evolved from and as you move forward in time they become increasingly less fish-like, more diversified and better adapted to terrestrial life. The first mammals to appear are virtually indistinguishable from therapsid reptiles and, again, as you more forward in time they spread out, become increasingly less reptile-like and more diversified and more like modern mammals. The first birds to appear are, quite literally, feathered dinosaurs and, once again, as new species appear they become more diversified, better adapted to avian lifestyles, they gradually lose many of the reptilian traits and look more and more like modern birds.
This exceptionless order is a fact that requires explanation. Evolutionary theory provides that explanation. It seems to me that anti-evolutionists have two possible alternative explanations for this. There is the YEC explanation, which is that all of these forms of life lived at the same time and were killed off in the flood, which sorted them into this order (the hydrological sorting position put forward by Morris, Gish, et al). This explanation is astonishingly ridiculous when you compare it to the evidence. There is no difference in the hydrodynamic properties of eukaryotic bacteria vs prokaryotic bacteria, yet the flood somehow managed to sort them perfectly into the same order all over the world? Raging flood waters managed to sort trilobites by the suture pattern on the insides of their shells or by the number of lenses in their eyes? Marine mammals somehow got sorted toward the top while marine fish got sorted toward the bottom? Not to mention that if all of the microscopic life whose bodies make up the vast chalk and limestone formations around the world lived at the same time the oceans would have been so thick with them that you wouldn’t have had to be Jesus to walk across it. Or that we find surface features at every level that could not have been formed in the middle of a flood (nesting sites, terrestrial sandstones, trackways, burrows, mudcracks, etc). How anyone with any knowledge of geology can take such an explanation seriously is beyond me.
The second explanation is that God created each of these life forms and did so in exactly the order that evolution would predict, putting them in exactly the right anatomical and temporal order so that it appears in an obvious pattern mimicking what one would predict if life evolved. Or perhaps that he was expirementing, creating new life forms trying to get to something novel and different until he got it right. Perhaps all of those hominid species that fall into the temporal and anatomical order evolution predicts to draw a line between the miocene primates and modern humans, with the signature human traits of brain size, dentition and bipedality gradually becoming more human-like over time, really represents a creator tinkering, making a series of almost-humans until he was happy with one of them and decided he had gotten it right. Needless to say, most anti-evolutionists can’t stomach the idea of a trickster God or a limited one trying to get it right.
So the challenge is this: what possible non-evolutionary explanation is there for the successional order of appearance noted here?