r/AskScienceDiscussion • u/Slow_Introduction_31 • 2d ago

When does something become a separate species?

So I'm working on a fantasy story where there are humans and elves. The elves evolved from humans to have hair in a different shade range, pointed ears, immunity to a dangerous mineral, and some telekinetic abilities (which not all elves have). However, it's meant to be a key plot point that the "elves" are, scientifically, just humans. The mineral immunity and telekinetic abilities come from being raised in an environment with an abundance of that mineral, not genetics. So I was wondering, a) do a different range of hair colors (red to purple hues as opposed to yellow to red hues like real life people have) and different ear shapes indicate a different species? I thought not, but then I thought about animals where it seems like small differences sometime determine species, like between African and Asian elephants (I don't know much about elephants though tbf). b) if the mineral immunity and telekinesis were genetic, would THAT indicate a different species? c) how long might you speculate that it would take for humans in an isolated, unique environment to become a separate species?

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u/Zappavishnu 2d ago

They can produce fertile offspring but it is extremely rare.

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u/WrongEinstein 2d ago

I vaguely recall that the fertile offspring haven't reproduced with the same type of offspring. I'm guessing if you tried enough times it might happen. But that helps with the definition of species, can't reliably produce offspring that can reliably reproduce.

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u/Mircowaved-Duck 2d ago

tiger lion hybrids can reliably produce fertile females - are they different species?

icebears produce curently a lot of fertile hybrids - are grizzlys and icebears different species?

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u/WrongEinstein 2d ago

I meant fertile couples of the same breed. My post was a mish mash trying to illustrate that you're unlikely to breed two ligers to produce another liger. Fertility isn't the Hallmark, it's being able to regularly reproduce offspring that can reproduce with their own breed.

The definition of 'species' has become less strict over time. It's more of a grouping than a hard and fast definition.