Well, this is true. And I see this as a rather significant challenge for YECs to explain. This doesn't mean they don't have explanations; only that I haven't seen an explanation that (to my way of thinking) satisfactorily explains the rapid rate of speciation needed to produce such a large number of species from such a small original population in such a (geologically and biologically)) short period of time. But basically they believe that speciation can occur,but it is constrained in the sense of only working within the limits of genetic variation found in kinds. But just because they haven't produced an explanation that is satisfactory to me does not mean they have not or never will produce one.On one hand they argue that macroevolution over long time scales is impossible but yet they seem to accept the idea that there was explosive speciation (evolution) after the flood. The use the same mechanisms as evolution does (selection, genetic drift, mutation) but this somehow happened in a geologic blink of the eye.
Well, this is not as problematic as you might think. Can biologists decide on a working definition of a species? There are likely a dozen species concepts I can think of, but this does not prevent a biologist from proclaiming that speciation has occurred. And I find this even more paradoxical when they use a biological species concept to define them, even though introgressive hybridization may occur - and sometimes commonly does between the two species in question. YECs are working on this, and there is a new and developing field called baraminology that seeks to define "kinds". I have been watching this with some interest in recent years. While I do not think their methods are objective and empirical enough to identify kinds (if, in fact, they do exist), they are decidedly more empirical than previous definitions (which usually involved something along the lines of "it's sort of synonymous with families, but we're not exactly sure").Not to mention that they cannot agree on what exactly a "kind" is.
It is a fair and valid question to ask.I continue to ask, where do YEC's draw the line for microevolution.
I wasn't aware it was "suddenly". But here are some tests I could think of: find a single vertebrate fossil in Pre-Cambrian rock. Identify a major group of organisms that arose before their most recent common ancestor in the fossil record. Reconstruct the phylogeny of a wide range of taxa and demonstrate that genetic discontinuity exists. Demonstrate that the Earth is geologically too young to have produced the genetic variety seen today from a common ancestor(s). Demonstrate that a group of organisms identified as closely related on the basis of comparative anatomy, physiology or morphology do not share the same patterns of relatedness based on genetics.Suddenly playing the devil's advocate now? How could they test something on timescales untestable?
Now, I am unaware of any compelling experimental data in any of these fields that that has, to date, done this. But to say that they can not disprove macroevolution is quite different than saying they have not.
Do we prove things in science? I thought that was mathematics...They could only test microevolution, which has already been proven.