@High Seas,
I dont think that its a too valid question to someone whos doing a synthesis of a bygone world. There are many exobiologists whove made predictions of what life would look like on another planet or on the earth if the O2 levels would again spike as they did in the CArboniferous and the Devonian.
Ive seen "futuristic depictions of lifeforms" that became adapted to a new environment. .
Im still fscinated by the use of the tools that I get from continental drift and paleontology because it helps me in my trade of minerals exploration .
SOmebody;s gotta do it.
Weve recently at the Apple laptop lab, constructed a computerized color chart that , based on Munsell numbers, can help us sort out layer information on specific fossils that are associated with baked deposits of specific clays. These clays attract and concentrate rare earths and minerals like lithium silicates and salts. )
Many of the genetic monstrocities that are the result of genetic engineering and artificial selection(like weird breeds of dogs), will, no doubt, revert to a general species more like a dingo. Hybridization always demands a loss in hybrid vigor. SO , if you wanna model that, you really have to exercise a bit of the HAldane dilemma because of the miniscule numbers of non interbreeding populations of all these hybrids.
The first varietals that go, (as defined by what we see in species extinction) is we lose the extreme end members (still using dogs as an example, wed lose chihuahuas and great danes and Irish Wolf Hounds, probably wed lose the Sharpeis and Tosa Inus and Irish setters. Ultimately , we be left with either , several species of dogs with interbreeding extremities, or else wed have a single species with a "bottleneck" and a high possibility for extinction because it takes a while to confer and rebuild hybrid vigor.
It took humans 70000 years to develop STR (Short repeat tandem alleles) that define hybridization"fingerprints" of the bazillions of local communities. Course thats just my guess. I wish tht reserach geneticist was still on the b oards, hed have a waay more intelligent guess than mine.