In my personal one, 2 beings are of the same species if they can reproduce and have their offspring be of the same species. Which means the offspring could theoretically breed with its parents.

Under this definition, a being can belong to multiple species.

So if A is the parent of B, and B the parent of C (because of evolution):

If B is similar enough to both A and C. But C is different enough from A, then B would be of both species A and C, like an intermediate between both species.

[–] technocrit@lemmy.dbzer0.com 2 points 7 hours ago* (last edited 7 hours ago) (1 children)

2 beings are of the same species if they can reproduce and have their offspring be of the same species.

This is a very incomplete definition though. For example is every mule a different species or not a species at all? Isn't a horse also capable of producing children of different "species"? I understand that mules might not be considered a species because they're sterile. But this ant isn't reproducing sexually either.

She was essentially cloning males from another species.

The "species" classification system is simplistic, somewhat outdated, and primarily basic model suited for children.

[–] calcopiritus@lemmy.world 1 points 5 hours ago

I'm no biologist. It's very possible it's an incomplete definition, and I don't claim it to be a perfect one.

I guess if we apply my definition to mules, each mule would be a different species lol.

The horses one is a non-issue though. It doesn't matter that they can create offspring of different species. Since 2 horses can potentially create a horse, then the horses are of the same species.

And yes, my definition works only for sexual reproduction, since as seen by this article, asexual reproduction can get very complicated.

I wouldn't say it's outdated and mainly for children. Just like Newtonian physics are very useful if we use it correctly. Having simple models that work in the situations we encounter most is useful even for adults.

[–] thebestaquaman@lemmy.world 3 points 8 hours ago

I'm pretty sure "can produce fertile offspring with each other" is a pretty common definition of a species. At least I've seen it before.

"Fertile" is key here, because while donkeys and horses can produce offspring (mules), mules are infertile, so donkeys and horses are different species.

So pretty much yes: While no single generation will differ enough from its parents to be a new species (at least very rarely), once you move a couple thousand generations, you can have a new species. However the point at which the new species "came into being" is very fuzzy.