How Long until a serperate group becomes a different species

[XaLEv]

You might consider having the differences be phenotypic rather than genotypic, that is, they're more or less like us genetically but they grow differently due to different environmental factors.

Like maybe they eat native organisms which contain chemicals that alter human embryonic development.

[Eternal_Freedom]

Interesting possibility. What differences might this make? Or, perhaps a better question: What kind of phenotypical differences would be realistic?

Obviously growing two heads and extra arms is out, but hair colour/skin pigmentation, that kind of stuff?

[Broomstick]

"Oh no! OncoMan is here! RUN BEFORE HE REACHES THE LYMPHATIC SYSTEM AND SPREADS TO THE ORGANS!"

Oh, that's just too fucking funny - thanks for making my day!

Interesting possibility. What differences might this make? Or, perhaps a better question: What kind of phenotypical differences would be realistic?

Obviously growing two heads and extra arms is out, but hair colour/skin pigmentation, that kind of stuff?

It's easier to stunt/deform growth than to give an advantage, but if the colony suffered, say, chronic calcium deficiencies that might render them extinct rather than separate.

Certain weirdnesses that already exists might become more common - for example, the hemochromatosis mutation could be an advantage in an iron-poor environment. Then again, that's not an adaption you can see, so nevermind I guess.

Too much silver in your system can result in argyria, which definitely is a visible change resulting not from genetics but from something ingested. It is apparently a cosmetic problem and does not otherwise cause physical harm. It is also permanent. How you'd "engineer" that into an environmental influence for your colony is up to you. Be creative.

Oh, by the way, it looks like this:



Eating too much beta-carotene is supposed to turn you orange, but that's not permanent.

I can't recall other environmentally induced weirdness at the moment, but then, I just got done with my fifth straight day of 10 hours shifts so I'm a wee bit tired.

You might also consider the "founder effect" for inducing visible differences in your colony in a relatively short time frame. That could, of course, also imply some inbreeding/limited gene pool as well.

[Alyrium Denryle]

Oh, that's just too fucking funny - thanks for making my day!

You're welcome. If you would like, I can continue the analogy/horror further...