I used to think that too, but apparently it’s not correct. Lions and tigers can produce fertile offspring, as can cattle and bison (to name a couple of instances). To me, the definition of species is a little fluid, since I KNOW I was taught (and taught when I taught HS biology) that if 2 creatures could breed and produce fertile offspring they were the same species.
susie
This is the admition I was looking for. ;)
This is true, since the terms are all what we humans use to try to categorize genetic differences. As we learn more, we keep redefining the terms we use. For example, the more we learn about the quality we call "intelligence," we find that some animals are not as "dumb" as we once assumed.
On the other hand, we find that the sub-species known as Marxist/Socialist, colloquially known as "liberal," is dumber than many animals. :)
I have read some speculation that man and chimp could interbreed.