I often hear evolutionists claim they "know how macroevolution occurs". If their claim is valid, then they should have no trouble explaining how, for example, the evolutionary ancestors of whales - ie, a rodent-like creature - could (hypothetically) be bred by humans to produce a whale (given unlimited time).
Thousands of years of animal breeding have demonstrated that there are real limits to how radically animals can be changed from their "original" form. For instance, wolves were bred to produce many different breeds of dogs, but harmful mutations limit how far this process can be taken. How can these genetic limitations be overcome to breed a whale from a sort-of-rodent?
"In his recent book, The Greatest Show on Earth: The Evidence of Evolution, Richard Dawkins observes airily that human beings are "distant cousins of bananas and turnips." Yet minutely observant plant breeders, "daily and hourly scrutinizing" their productions (to quote Darwin on natural selection), are unable to turn purple roses into blue ones." (Tom Bethell, Natural Limits to Variation, or Reversal to the Mean: Is Evolution Just Extrapolation by Another Name, evolutionnews.org)
"The available data of biology indicates that in contrast to evolutionary theories, there is sufficient evidence to suggest that biological change has limits." (Lane P. Lester and Raymond G. Bohlin, The Natural Limits of Biological Change, 1984, p.149)