You did. My comment was referring to the post I was responding to, in which I only found that aspect in need of a reply.
my interpretation would be more along the lines of: "sub-species which do not naturally produce viable offspring have become separate species."
OK. Then there is no argument: according to this definition that third kind of zebra is a new species. But the definition is flawed: if you define species by their behavior in mating, then dogs are also not a single species, because big dogs and small dogs do not naturally interbreed: the hydraulics and the mechanics don't work. Also - as I noted before more than once, -- humans, too, have breeding preferences which they do not cross other than in "captivity" of some kind, i.e. are forced to or exchange reproductive products through things like sperm banks.
The definition of species, in my mind, needs to include other factors: can the specimens be bred in a lab? do they look alike? does the offspring itself reproduce? These are all factors generally recognized as a part of a definition: Species problem.
According to the latter, all these zebras are breeds of the species zebra.
Note, too, that this quadrille about definitions does not help the evolutionist myth. Sure one can define species so that they "evolve" all the time. But then you discover that maybe they do "evolve" according to your particular definition, but that "evolution" still confines the "evolved" specimens to a boundary that is not crossed. Evolution postulates that bona fide species evolve into species different in many ways. Further, the evolutionary hypotheses speculates that genera boundaries are crossed as well (e.g fins become legs, front legs become wings, etc.). So your zebra example falls still short: you simply adapted your definition of species to be narrow enough for it to show "speciation".
Dogs and wolves still interbreed, so by scientific definition, they are still the same species.
They interbreed under special conditions: in a lab, involving feral dogs, in captivity, etc. They do not naturally interbreed when mates of their own kin are available. I agree they are the same species, but so are the three zebras.
But other differences could not happen until DNA mutations came along to cause them.
But they are mutations inside the genome of an elephant or of a dog. They may help in artificial selection, but they do not work across species or at least across related fuzzy group you insist on calling separate species.
This would, indeed be a good avenue of research to pursue for someone interested in proving macro evolution. Start with a dog, and make a cat. Or the other way around. Or anything that is a non-dog and itself can breed. That would prove that random mutations with selection produce something selection alone could not produce.
That would also be what the scientific method calls for: test your theory with experimentation.
What exactly is your problem with biological classifications into breeds, sub-species, species, genera, family, order, class, phylum, kingdom & domain?
These are all scientific classifications, each has criteria and every living thing is assigned its classifications according to those criteria.
So, if you wish to debate whether a certain creature belongs in this breed or that sub-species, it's a debate you can have -- with scientists who specialize in those issues.
I note, to pick an example, that African Elephants are not just a separate species from Asian Elephants, they are a separate genus, and that while African Elephants consist of two different species, Asian Elephants have only one species, but four sub-species.
Sub-species? Species? Genera? Where are the scientific dividing lines, you might ask?
Clearly these are matters for scientists to establish or debate, but the basic idea is that "species" is the rough dividing line between those groups which can interbreed and those which cannot.
In the case of elephants, fossil and DNA evidence shows African and Asian elephants split over 7 million years ago, and after 7 million years they are separate genera, which do not interbreed.
Contrast the case of dogs which were split from wolves only about 15,000 years ago, and which do readily interbreed.
Dogs are classified into breeds, together a separate sub-species from wolves.
Now consider normal DNA mutations, let's say at 50 per generation.
Among elephants over 7 million years of separation, we're looking at about 35 million mutations or over 1% of the elephant genome.
And that 1% is enough to physically prevent African and Asian Elephants from interbreeding.
By contrast, dogs over a mere 15,000 years of separation from wolves would accumulate only .01% mutations in their DNAs -- not enough to prevent interbreeding.
I ask again, what exactly is your problem with biological classifications?
annalex: ""According to the latter, all these zebras are breeds of the species zebra."
According to who? According to you personally?
Well, isn't that special?
Science has methods for classifying things.
I prefer scientific classifications.
In scientific classifications, all Zebras belong to the genus Equus, and are divided among two sub-genera, three species and seven living sub-species.
If you wish to see them all re-classified you'll need to discuss that with the "scientific classification board". ;-)
annalex: "Further, the evolutionary hypotheses speculates that genera boundaries are crossed as well (e.g fins become legs, front legs become wings, etc.).
So your zebra example falls still short: you simply adapted your definition of species to be narrow enough for it to show "speciation". "
There are no physical boundaries -- "boundaries" are a religious idea, not scientific -- in science the only real "boundary" is whether some group can interbreed with another, and even that, as you've noticed, is not so firmly fixed -- i.e., interbreed under which conditions, exactly?
So no species "crosses a boundary", it simply evolves, slowly, slowly, one generation after the other, until by various methods scientists can begin to see signs of separate breeds, then sub-species, species, genera, etc.
No "boundaries", just continuing evolution -- or if you prefer, "punctuated equilibrium".
And truly major changes do not happen at the breed, sub-species or even species levels.
The fossil record and DNA analyses show major changes happening over millions, tens of millions of years.
annalex: "I agree they are the same species, but so are the three zebras."
I'll refer you again to the "scientific classification board", and if they agree that you have a better classification system than they developed, I'll accept their and your judgment on the matter.
But if for some strange reason they don't agree with you, then I'll go with their judgment over yours, FRiend. ;-)
Seriously, who outside a scientific specialist would ever even care whether Zebras fall into one genus with two sub-genera, three species and seven sub-species -- as scientists tell us -- or whether they are all just one species with numerous sub-species, according to the "annalex classification system"?
annalex: "But they are mutations inside the genome of an elephant or of a dog.
They may help in artificial selection, but they do not work across species or at least across related fuzzy group you insist on calling separate species."
There you go again with that "across species" talk!
When creatures evolve, none of them -- zero, zip, nada -- know anything about a "species boundary" they are somehow not allowed to "cross".
Where did you get that idea?
I'm telling you, it's not from science -- it's some weird notion you have, and nothing to do with reality.
Species simply evolve (descent with modifications and natural selection) and adapt as best they can in changing environments.
They don't stop evolving just because they've crossed the "annalex species boundary".
annalex: "This would, indeed be a good avenue of research to pursue for someone interested in proving macro evolution.
Start with a dog, and make a cat.
No need, it was already done, by God, roughly 42 million years ago when He split up the Family of Miacids (primitive carnivours) into various carnivorous Orders including cats and wolves.
So 42 million years of evolution separate cats from dogs, and that will not be repeated in a lab anytime soon.
But, the actual DNA mutations, generation by generation, just might be reconstructed experimentally in a super-computer, in effect working backwards through time to genetically recreate the common ancestors.
Interesting thought... hmmmmm... let's see, if I were in charge of the scientific enterprise, I think I'd put that the "to do" list right after they complete the task of mapping out the DNA genomes of every living creature.
annalex: "That would also be what the scientific method calls for: test your theory with experimentation.
I'm sure, if you wish to design and propose a scientific experiment, there will be some government agency with money to fund it. ;-)