They go after me a lot at the Uncommon Descent website, a vehicle for intelligent design [ID] creationism, and I usually ignore them. But their latest tirade is so ludicrously ignorant that I have to single it out. Here it is in full:
What a thicket of ignorance we must chop through here! My response is fivefold:
1. To change something like a cat into something like a dog through artificial selection involves modifying not just its morphology, but its physiology, its brain, its neurology, and its (hard-wired) behavior. That would take a gazillion generations of artificial selection. I have no doubt we could do this had we thousands or tens of thousands of years to do that kind of breeding, but a) we haven’t because b) nobody’s interested in doing that. Nevertheless (go to #2),
2. Artificial selection clearly has created forms that, if found in the fossil record, or if you saw them and didn’t know they were products of artificial selection, would clearly be regarded as different species. Here’s what humans have done to the wild mustard in just a short span of time:
All seven descendant vegetables have the same common ancestor, and were bred for various traits (the odious Brussels sprout, for example, for small unopened heads). Does anybody doubt that if we found fossil impressions of these, or saw them growing as wild plants in nature, they’d be regarded as different species, or even different genera?
And then there are these:
As I document in WEIT, there is much more variation among living breeds of dogs—artificially selected within the past 10,000 years at most—than there is among the wild species of canids in nature. If dog breeds like the two above were found in the fossil record, they’d be regarded at least as different species, or even different genera (remember that Australopithecus and Homo are different genera). That’s a remarkable transformation in a short period of time.
Now I don’t regard the different breeds of dogs as biological species in the sense that, by breeding between different pairs (in the case above, mating the small dog to a slightly bigger dog, and its hybrid to an even bigger dog, and so on), you could conceivably mix the genes of any two breeds, and that miscibility is the hallmark of “biological species”. But that’s only because breeders have not selected for reproductive incompatibility between breeds, but for morphological and behavioral differences. We can’t test the ecological differences between breeds (though a Chihuahua and a mastiff surely are completely isolated sexually), but it would take longer to get reproductive incompatibility via hybrid sterility and inviability, which normally result from the interactions between many genes. Artificial selection doesn’t usually create that kind of extensive genetic change. Nevertheless (go to #3),
3. Researchers in the lab have successfully created reproductive isolation between forms (“species,” if you will) via artificial selection. This has been done in several studies of Drosophila (see my book with Allen Orr, Speciation). In fact, one experiment by Bill Rice and George Salt produced almost complete ecological isolation between two sublines of a single species (D. melanogaster) within only 30 generations of selection—roughly a year in the lab. That’s remarkable, for, as Rice and Salt say in their paper, “One of the principal difficulties with the study of speciation is that it occurs quite slowly on a microevolutionary scale, despite its apparent rapidity in the fossil record.”
Further, as I also documented in WEIT, botanists have created new plant species in the laboratory through polyploidy, precisely mimicking a process that occurs often in nature. (Anywhere between 2 and 10% of new plant species form through polyploidy, and others arise through diploid hybrid speciation, a process also duplicated in experimental studies of plants). We’ve even made, in the lab, the same species that have arisen in nature, simply by crossing the same two parental species that gave rise to the new polyploid species in the wild.
4. And, of course, there are all those transitional forms in the fossil record showing that, despite the IDiots’ objections, new genera, families, and even orders have arisen through natural selection. Here’s one such transformation—the evolution of whales from a terrestrial artiodactyl (even-toed ungulate) ancestor:
We have all of those transitional forms, and they occur in the order given.
Here’s a likely starting point, the putative ancestral form Indohyus, a small, deerlike creature with many features that show both semiaquatic behavior and morphological adaptations that could be precursors to those of modern whales,
Here’s one descendant:
How long did this transformation take? Only eight million years! Remember that humans are only five or six million years removed from our common ancestor with chimps, and the difference between ourselves and chimps (in terms of morphology) is far less than the difference between Indohyus and modern whales.
And there are, of course, the many transitional fossils between fish and amphibians (e.g., Tiktaalik), between amphibians and reptiles, between reptiles and mammals (the so-called “mammal-like reptiles”), and between reptiles and birds. Oh, and also between hominins in the lineages spanning Australopithecus to modern humans. But IDers don’t like to talk about that transformation. Yes, Jon Wells and Michael Behe are African apes.
5. The unknown IDer who wrote the screed above claims that I don’t get to decide what is or is not a serious objection to evolution. True—I don’t, not by myself. But the scientific community does, and that community does not include the religiously-motivated proponents of ID.
Further, “what is objectionable to others” is not the criterion for what we consider a serious problem with evolution. When a serious scientist like Steve Gould asserts that the pattern of evolutionary change is jerky rather than gradual, we pay attention. When religiously-motivated creationists like those at the Discovery Institute argue that major evolutionary transitions can’t occur because we haven’t bred a cat into a dog, we don’t pay attention. That’s because that argument was already debunked long ago—any natural history museum instantly shows its error. For the same reasons we don’t need to pay attention to the arguments of Holocaust deniers and flat-earthers. The people who determine what is a serious objection to a well-founded scientific theory are other scientists, for that’s who we listen to when judging the merit of our own results.
And by “other scientists,” I don’t mean Bible-thumpers with Ph.D.s, like Michael Behe. Their motivation is not the honest pursuit of truth, but the glorification (and verification) of God by debunking His most powerful enemy: natural selection.