Name for Fertile and Infertile Hybrid animals and Species Classifications.

Question

If you have two distinct species of animals that are closely related, are they a Sub Species?

Are they a Sub Species if they can breed and produce fertile offspring? What if they can not produce fertile offspring or not reproduce together at all? Is there a name for two species that are closely enough related to eachother that they can produce offspring, but the offspring is sterile? such as a horse and donkey making a mule?

Is there a different word for two distinct animals who can produce fertile offspring and are even capable of creating a new species all together, such as Coyotes and Wolves?

How are Breeds of Dogs different from Sub-Species, on a genetic level?

Answer 1

Two closely related species would be considered to be within the same "genus". If two organisms are closely related and able to produce fertile offspring, then they are within the same "species". "Subspecies" refers to the geological separation between individuals within the same species, which results in the some members to exhibit different phenotypic (i.e. physical) characteristics due to evolutionary adaptations to their environment. For example, if a species of becomes separated by a mountain range, and Group A finds different resources to hunt/eat/forage, then this separated Group A will appear slightly different than the Group B on the other side of the mountain.

If two closely related species can mate, but their offspring are infertile, then this is often referred to as a "hybrid".

Different breeds of dogs, cats, and other domesticated animals are unusual because humans bred animals specifically for certain traits. Another way to think of it is that "breed" is a smaller population within a "species". Sort of like the "subspecies" example above but with human interference.