Levistus's_Leviathan
5e Freelancer
There is not universal term for species. No matter the definition and no matter how airtight it seems, like the fertile offspring rule, there's always exceptions that make the definition not work in certain circumstances.
There's a species of newt that has 7 subspecies. Each subspecies can breed with any other subspecies, producing fertile offspring of one of the parent's subspecies. There's an exception, though. There are 2 subspecies in this species of newt that cannot breed together, can't even produce infertile offspring. Both of these subspecies can breed with any other subspecies in this species of newt, but they cannot breed together. If one specimen from either subspecies breeds with another subspecies of newt that it can breed with, if its offspring is a member of the other parent's subspecies, it can breed with the subspecies its parent could normally not breed with.
This is an example of a species that doesn't follow standard species classification. Based on the "a species is any group of creatures that can breed and produce fertile offspring" definition, this newt should be one species, as they can almost all interbreed. Also according to this definition, the 2 subspecies that can't breed together are different species of newt. This definition doesn't work for these newts and is inherently flawed for other types of creatures.
There's a species of newt that has 7 subspecies. Each subspecies can breed with any other subspecies, producing fertile offspring of one of the parent's subspecies. There's an exception, though. There are 2 subspecies in this species of newt that cannot breed together, can't even produce infertile offspring. Both of these subspecies can breed with any other subspecies in this species of newt, but they cannot breed together. If one specimen from either subspecies breeds with another subspecies of newt that it can breed with, if its offspring is a member of the other parent's subspecies, it can breed with the subspecies its parent could normally not breed with.
This is an example of a species that doesn't follow standard species classification. Based on the "a species is any group of creatures that can breed and produce fertile offspring" definition, this newt should be one species, as they can almost all interbreed. Also according to this definition, the 2 subspecies that can't breed together are different species of newt. This definition doesn't work for these newts and is inherently flawed for other types of creatures.