So creationists most certainly accept the existence of biological variation and speciation. Creationists call this rapid diversification from “kinds” down to modern species “microevolution.” However, the mechanism they propose as the basis of “microevolution” differs broadly from the mechanism accepted and taught as part of the theory of evolution.
[…]
The creationist model claims that the variation provided by Mendelian inheritance and genetic loss – this “microevolution” mechanism – is responsible for all the variation we ever observe in nature. They claim that this observed level of variation is sufficient for the diversification of the 10,000 kinds represented on the Ark, but – they claim – not sufficient to produce the new genetic information needed to produce all life from a single common ancestor (what they term “macroevolution”). By erroneously supposing that Mendelian recombination is the exclusive source of genetic variation, they neatly exclude any viable mechanism for universal common descent.
Correcting this misconception can be difficult. It is not enough to explain that macroevolution is the accumulation of microevolution over time, because creationists define these as two distinctly different processes. They actually are correct in arguing that their “microevolution” could never accumulate into “macroevolution” because their definition of “microevolution” is much more limited than we see in reality. They must be made to understand that the genetic variation we actually observe on a daily basis is fundamentally different than what their “microevolution” allows for. (Emphasis in original)
Part 2 can be found here.
