However, evolutionists are being disingenious when they slam the concept of a "kind" as if they are not in the same boat when it comes to classifying creatures.
Actually not really. Evolutionists recognize that such concepts are merely conveniences, that they are simply man made classifications that make our life easier. Evolutionists make no absolute statements about what a species can or cannot do other than in the defining of the species...and whenever they define a species they recognize it as being an illusory concept...so if they define species as being a collection of interfertile organisms, they will recognize that a seperate species can be interfertile with mixed success.
Creationists categoricaly state that all organisms multiply after their kind. That any descent with modification is limited to this concept of kind. That their is a 'kind barrier' of sorts. They make an absolute statement about kinds but give no absolute definition of kind...thus their idea gets slammed.
That would be like a physicist seeing a problem with QM and proposing that bosons can never pass or interact beyond the Modulous barrier. When asked what this modulous barrier is they say "it's the thing that bosons can't interact beyond'. When asked how they know of this barrier they say "Well...we've never seen a boson interacting with anything on Tau Ceti, so there must be a barrier between here and there that stops this".
My point is regardless of the definition there are some concrete parameters that nature works in, as far as sexual reproduction.
Then again, I don't think that is strictly true. As far as I am aware some hybrids are a hit or miss kind of affair. Sometimes the breeding fails entirely, or the hybrid isn't fertile, or the hybrid doesn't survive to maturity. There are species that are perfectly interfertile but will refuse to breed with one another (failure to recognize mating signals etc). Its a spectrum that peters out to nothing, not some concrete parameter. The only thing we would agree on is that there a place on this spectrum where we can say that interfertility reaches 0.
As far as hybrids that can produce fertile off-spring, maybe the correct answer is to consider them just one species despite the fact this can occur even across genus and sub-families, (pseudorca and certain kind of porpoise for example).
Perhaps, but then that gets a bit crazy and counterintuitive. Instead its probably easier to simply refer to them as seperate species that are interfertile.
I think we'd agree that if 2 species can interbreed, they were once joined as one species.
Well, given that you know about common descent, you'll know I agree with it. If you can agree with it then that's great.
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