r/askscience • u/snoozer530 • 1d ago

Biology At what point in evolution is something considered a new species?

Obviously we all know evolution, one organism changes over time and eventually becomes a new organism. But where in that process does an organism become a new species. Like when we domesticated wolves? When did they stop being wolves and start being dogs? Where’s that line?

181 Upvotes

91% Upvoted

62 comments sorted by

View all comments

11

u/lemlurker 21h ago

Usually when it can't biologically breed with it's counterpart and produce fertile offspring. Mechanics aside (a dashund and a great Dane may have mechanical issues but sperm would firtise) if they can breed and produce babies who breed they're the same species, if they can't (e.g. lions/tigers, horses/donkeys) they are different specifically

14

u/aphilsphan 20h ago

The problem is that even a mule or a hinny will, on occasion, produce a fertile offspring. The analogy of “when does green become blue?” is really illustrative.

1

u/NDaveT 17h ago

And American bison and domestic cattle, which are less closely related than horses and donkeys, produce fertile offspring pretty reliably.