|
Post by speakertoanimals on Jan 27, 2011 16:50:03 GMT 1
So, should only take a few years to re-evolve Polar bears then.............
'Recent' doesn't mean last week you know..............
|
|
|
Post by carnyx on Jan 27, 2011 17:24:33 GMT 1
The obvious question is: although they are claimed to have emerged 150k years ago, how long did the transition take?
Bearing(!) in mind that they have around 15 to 20 generations per century as opposed to Humans about 4 to 5, and that the fair-skinned population of humans emerged around 10k years ago, that could them an equivalent period of 2 to 3k years for white bears to re-emerge.
And the fact that can still interbreed, makes then strictly the SAME species.
I mean, if you can't use the argument that they are two separate species " because they have different morphology, metabolism, social and feeding behaviors, and other phenotypic characteristics" for Aboriginals, why accept it for Bears?
|
|
|
Post by speakertoanimals on Jan 27, 2011 17:42:33 GMT 1
Rubbish. Tigers and lions can interbreed, no one calls them the SAMe species.
Try looking up ring-species, the species concept is more COMPLICATED than the simplistic - if they can interbreed they ain't-- one that you seem to prefer.
I prefer what biologists have to say, who think that having polar bears as a separate species makes sense. Even if they weren't, they are still a phenotypically-distinct group.
Unlike humans, actually, where the genetic diversity across ALL human populations is way less than among other great apes. We are more alike that you would expect.
O, and they're not albinos either, they have black skin under that yellowy fur. And dark eyes.
|
|
|
Post by carnyx on Jan 27, 2011 17:50:29 GMT 1
Bollocks.
Don't you read your own quotes?
And then quoting Lions and Tigers is very very weak. Suprised you did that, considering.
|
|
|
Post by speakertoanimals on Jan 27, 2011 18:21:44 GMT 1
I never SAId they couldn't interbreed, just that being able to does NOT (whoops!) mean they are the SAME species.
Your labybird book of biology might have said that, but current use of the species concept is a bit more sophisticated.
I refer you again to ring species.
And humans -- we have very little variability, compared to any other great ape.
WHY don't you want polar bears to be considered a separate species, that's the question, because I doubt you care that much about abstract aspects of taxonomy.............................
|
|
|
Post by speakertoanimals on Jan 27, 2011 18:24:34 GMT 1
Why so? Most people are perfectly happy that they are separate species, and also quite surprised when they learn they can interbreed, and sometimes produce fertile hybrids.
Mind you, if you really want to twist your head as regards species and the species concept, go look at trees!
After that, deciding it is okay to call a polar bear a separate species is trivially easy...........
|
|