"The animals on the ark would repopulate the world by migrating away from the ark landing site. The mountainous area around the ark would be ideal to encourage successful repopulation, as a mountainous area contains varying ecological zones and would tend to fragment the growing population into sub-populations (different "herds") giving the animal type multiple chances to avoid extinction. Inbreeding within these sub-populations would also cause differing traits to become dominant within each sub-population, leading to the formation of what we now call different "species" ("rapid speciation"). It is important to remember that speciation (the formation of a new species) is NOT evolution, as no new complexity is being introduced, only the rearranging of existing genetic information. We must also remember that it was God who made the final selection of the animals for the ark. This was necessary as only God could know the genetic makeup of the individual animals, and it was important to choose animals having the widest range of genetic potential. But even if this were not the case, it is true that most of the potential variation of any type of animals will be found in every male/female pair. There are modern day examples of a pair or small number of individuals successfully starting a repopulation effort that eventually leads to a diversified population exhibiting much variation (such as the rock pigeon introduced into the USA from England)."
http://emporium.turnpike.net/C/cs/ark/sld020.htm
Why not? Are you saying that is impossible?
How do two individuals possess the genetic variation, without evolution (or even with evolution in such brief time time spans!), to produce 150 species, and only on average mind you, and many with distinct and peculiar adaptations, in a few thousand, or even an initial one or two thousand, years!?
It out does anything the most wildly liberal evolutionist would ever propose by orders of magnitude. Evolution maybe produces 1 or 2 or maybe, in a good year, a few dozen new species a year (usually maintaining a steady state with extinctions). Additionally those new species are very similar to the immediately preceding types. They may have a bigger bill, or a couple extra teeth, or slightly longer incisors, or a larger or smaller body size, or different coloration, or a different call, a different courtship dance, or some subtle variation in behavior allowing them to survive in a slightly different ecological niche. But your creationistic non-evolution-evolution produces species adapted to radically new, and often very harsh, environments almost instantaneously.
You're right. It's not "evolution". It's "hypervolution".
Consider JUST the amazing adaptations of deep sea fishes. There is virtually no light, so many species produce their own by bioluminescence. The protein density is usually extremely low (in the deep oceans but above the sea bottom, in the "mesopelagic" zones) so many species have to get by with a half to a third of the protein content in their muscles compared to "normal" oceanic fishes.
And of course there's the incredible pressure: 400 times atmospheric pressure at 4,000 feet deep. Can you imagine how difficult it is to inflate a swim bladder, and keep it inflated, at that depth? Especially when your muscles are much weaker (see above) than those of normal fish. Just this feature alone would have had to have been radically redesigned (simultaneously in multiple "kinds") with respect to pre-flood fishes which never experienced such pressures.
And that's not the half of it. Not even a fraction of it. For instance the whole biochemistry has to be different, or specially adapted and enhanced. These extreme pressures force water molecules to stay tightly bound to charged molecules. This interferes with crucial binding events in cells, for instance enzymes binding to energy-yielding molecules like ATP.
And all this had to "evolve" (without evolution!) hundreds of times in just the few thousand years since the flood.