But biologists *do* classify lions and tigers as separate species, so you are apparently confused on how the term is used by the biological community.

THAT is the whole point!

The distinction is arbitrary!!!

If we look at organisms, they do tend to group into breeding populations that maintain their distinctive characteristics.

Another argument against Common Descent.

Thanks Zach!!

And in doing so I was illustrating the absurdity of the debate with absurdities.

Whether you were serious or just funnin’ them poor dumb critics for effect, you were attributing to biologists a single definition for what makes a species (reproductive isolation) which they demonstrably don’t hold. Misrepresentations like that don’t make your case any stronger.

Have a nice Thanksgiving if you are in the US.

Let me see if I got this right. You call me clueless, sarcastic, brainless, courageless, and heartless. But you wish me a Happy Thanksgiving, as if a throwaway pleasantry absolves you of your previous incivility? What can I say but Happy Thanksgiving and make enough stuffing to fill two turkeys.

jerry: I suggest that anyone quibbling with my comments about what a species is go to the biological community and change their definition of species because you have special insight.

But biologists *do* classify lions and tigers as separate species, so you are apparently confused on how the term is used by the biological community.

You are correct that reproductive isolation is an important aspect of speciation. But isolation can be partial and can grade between varieties. And even what were thought to be isolated populations can hybridize sometimes (e.g. brown bears and polar bears). But it’s not a smooth continuum. If we look at organisms, they do tend to group into breeding populations that maintain their distinctive characteristics.

You might take a look at John Wilkins’ book, Species: A History of the Idea. He discusses many of the various related concepts.

Just a little bit of a clue for the clueless. I was responding to another commenter who seemed not to understand the debate. And in doing so I was illustrating the absurdity of the debate with absurdities. The whole debate is about the origin of species and it is clear that this term has no good meaning. We as well as the rest of the biology community have discussed this several times. To see a more recent discussion go to ITunes university and download the Stanford Darwin series lecture by the Grants on the Galapagos finches. Charles Darwin wrote his book about this absurd term which has no real meaning. By using tigers and lions, my favorite absurdity, I was illustrating to the commenter some issues.

Then you butt in with your sarcastic put down like it was new and us country bumpkins have to be straightened out. And then you continue on to defend your irrelevant examples which we all know about. We can read Wikipedia too and know how they are supposedly classified. Way to go with your insight. We can now go home.

“Scientists consider horses (Equus caballus) and donkeys (Equus asinus) different species, too.”

My God, the ID movement can now shut down because we have finally been shown the light. We know everything you have said so you are only repeating the obvious. And in truth it is all irrelevant to the debate. So getting irrelevancies from critics here is nothing new for us. It is what one does when they have nothing of substance to contribute. So continue with your ass-inine examples and by mutation and natural selection we mayl finally see something interesting some day. It is as rare from the anti ID crowd as the generation of a gene de novo.

What is missing from those who come here and criticize is brains, courage and heart. In the Wizard of Oz, the scarecrow, Tin Man and lion were missing just one each but the critics here seem to missing all three.

And I am cleaning and helping with food preparation for Thanksgiving so I am standing except to write this but I will manage. Thank you for my concern. So thanks for advice. It is as good as any we have received here recently from those who criticize us. It is the level we come to expect.

Have a nice Thanksgiving if you are in the US.

Scientists consider horses (Equus caballus) and donkeys (Equus asinus) different species, too.

Yeah, well, that’s just a bunch of ***inine horse****.

Scientists consider horses (Equus caballus) and donkeys (Equus asinus) different species, too.

And then the person uses the comment “oh my” like it is my comment that is flawed when it is his understanding that is problematic.

Umm, Jerry, it was a reference to the Wizard of Oz. “Lion and tigers and bears, oh my!” Remember now? It was intended as light humor. Sorry about that.

I suggest that anyone quibbling with my comments about what a species is go to the biological community and change their definition of species because you have special insight. They would laugh you out of the room.

It was the scientific community that classified tigers (Panthera tigris) and lions (Panthera leo) as different species. The same community that classified cattle (Bos primigenius) and bison(Bison bison) as different genus and species. So, it is you, not me, that has some ‘splaining to do! (BTW, that is an “I Love Lucy” reference.)

Now here is a comment by someone who is quickly demonstrating that he should not be paid attention to. Instead of saying, yes the accepted definition of species (and by the way I can show you discussions about just what a species is and that in the past I have brought up this specious definition of species as having difficulties) has problems and then moving on, he tries to defend his lame comment. So you already disqualified yourself as a serious commentator and just one who wants to quibble over minutiae.

And then the person uses the comment “oh my” like it is my comment that is flawed when it is his understanding that is problematic. It is just another indication of attitude of someone who has nothing to say except to take some shots at someone. And then someone tries to defend him with the obvious example that is well known to everyone of A mating with B and B with C and A can not mate with C. How pathetic is that.

I suggest that anyone quibbling with my comments about what a species is go to the biological community and change their definition of species because you have special insight. They would laugh you out of the room. Everybody knows the problems with the definition but they must have something or else what would that book, Origin of Species be but specious. It is specious anyway even if species were in fact completely separate entities.

The problem is that all of evolutionary biology is specious.

The borders of a species can be fuzzy and chaotic, and many species hybridize, especially in plants. The gray zone between species is considered important evidence in support of the Theory of Evolution, and has been since Darwin.

It is because those borders are fuzzy and chaotic that we do not expect to see a nested hierarchy constructed via descent with modififcation/ Common Descent.

That is because nested hierarchies require distinct categories that transitional forms would violate.

As for lions and tigers- try telling them apart given only their bones or fossils.

Good luck with that…

jerry: Look up Ligers and tiglons. They can interbreed so they are the same species.

Lions and tigers are both members of the genus Panthera. There is virtually no gene flow between wild populations; and hybrids, if they occur, are very unlikely to mate and continue the line. Compare to humans, who readily mate wherever and whenever given the opportunity, and where there is a great deal of mixing between subpopulations throughout their geographic range.

Even if we were to adopt such a stringent definition, it doesn’t remove ambiguities. Variety A may mate with Variety B, which may mate with Variety C, but A may be unable or unwilling to mate with Variety C.

Generally, a species is a breeding population that maintains a set of distinctive characteristics. There are a number of operational definitions that are used, depending on the field of study. This can lead to some ambiguities, of course. The borders of a species can be fuzzy and chaotic, and many species hybridize, especially in plants. The gray zone between species is considered important evidence in support of the Theory of Evolution, and has been since Darwin.

Species is a difficult concept, but lions and tigers are clearly separate species, so your understanding is in error.