Well, my Maine Coon is also a cat, but no way he's breeding with a female tiger. Though I'm sure he'd give it the old college try.
The liger example shows, IMO, that speciation is a gradual process with lots of gray areas. As species drift further apart, such as house cats and lions, it becomes clear that they are distinct. However, some species are still close enough that thay can interbreed.
Precisely what we'd expect if the theory of common descent were accurate. All life is a continuum. Alas, large chunks of are extinct, but as fossils are found, they fit right in. As predicted by the theory:
All present and fossilized animals found should conform to the standard evolutionary tree. And they do.
Fossilized intermediates should appear in the "correct" chronological order on the standard tree.
After reading 350 of these threads, it appears to me that the word species is loosely-knit.
Creationists admit to speciation within kind. Man's demonstrated that with dogs, horses, pigs, cows, etc.
But just because a lion and a tiger can mate with mixed results, doesn't prove either that they were created separately or that they are an example of genetic sorting from a common ancestor. And even scripture doesn't help me out much there.
But to go from a hippo to a whale. That's just not believable.
...albeit with varying levels of success.
"...The liger example shows, IMO, that speciation is a gradual process with lots of gray areas. As species drift further apart, such as house cats and lions, it becomes clear that they are distinct. However, some species are still close enough that thay can interbreed."
Exactly.