thestyleguy wrote:I read that about five or six million years ago some species split and then a million years ago they got back together for a short time and then split again -
Stuff like that happens. Sometimes it is a trial separation before the big split. They end up saying can't live with them but can live without them. Hopefully it was amicable.
To the other good comments (Sethbag's, etc.) I would just point out that any complete definition of what a species is would involve a series of cumulative genetic changes that bespeaks a... wait for it... conitinuum (!) to ultimately bring about a difference that we humans would dub [a distinct species].
So by definition, species exist on a continuum.
"And yet another little spot is smoothed out of the echo chamber wall..." Bond
Thanks, the dude. But I really can't see how failure to interbreed works then. Wouldn't this require there to be at least one species of beings right now that was close to us genetically, but with which we humans could not produce offspring? Who or what would that be?
charity wrote:Thanks, the dude. But I really can't see how failure to interbreed works then. Wouldn't this require there to be at least one species of beings right now that was close to us genetically, but with which we humans could not produce offspring? Who or what would that be?
That depends how 'close' would be close enough for you. We cannot interbreed with chimpanzees, although even on recent reduced estimates we still share 95% of our DNA with them:
Chap wrote: That depends how 'close' would be close enough for you. We cannot interbreed with chimpanzees, although even on recent reduced estimates we still share 95% of our DNA with them:
It isn't what is close enough for me. It is what is just one step away from interbreeding. So theoretically speaking, could there be human populations on earth at present which could not interbreed?
Chap wrote: That depends how 'close' would be close enough for you. We cannot interbreed with chimpanzees, although even on recent reduced estimates we still share 95% of our DNA with them:
It isn't what is close enough for me. It is what is just one step away from interbreeding. So theoretically speaking, could there be human populations on earth at present which could not interbreed?
Well, I was trying to respond to your question, which is meaningless unless you tell us what you mean by 'close'.
As to the new question you put here, I suspect you will find that an expert (like The Dude) would say that part of the meaning attached to calling some population of anthropoids 'human' is that we CAN interbreed with them. It is more a matter of definition than of experimental fact.
Fortunately the days are past when there were serious arguments about who was human, and who was not.
I am trying to understand the mechaism by which evolultion has occurred and the point at which two individuals are "close" enough to consider each other possible mates and yet not be fertile.
Since the experts haven't responded here is my very non expert thoughts. :-)
I am trying to understand the mechaism by which evolultion has occurred
What do you mean by this? Evolution IS a method/process. hmmm.. Can you clarify?
the point at which two individuals are "close" enough to consider each other possible mates and yet not be fertile.
If I'm understanding your question correctly, when you say, "individuals" are you meaning animals?
Generally speaking, a new species is created as a group of a particular species moves into a new environment and due to adaptation evolves in ways differently than the original group. Depending on the life form, it takes some time to completely evolve enough to become a separate species. The specific "point" where a couple could no longer be fertile would be determined by the type of species and the rate of evolution/adaptation.
At least that is how I understand it. :-)
~dancer~
"The search for reality is the most dangerous of all undertakings for it destroys the world in which you live." Nisargadatta Maharaj
truth dancer wrote:Since the experts haven't responded here is my very non expert thoughts. :-)
I am trying to understand the mechaism by which evolultion has occurred
What do you mean by this? Evolution IS a method/process. hmmm.. Can you clarify?
The mechanism by which the process works. Supposedly we start with an ameoba, and now there a hundreds of thousands of different species who are not able to mate. Without multiple, highly unlikely, parallel mutations, how does this happen.
truth dancer wrote:
the point at which two individuals are "close" enough to consider each other possible mates and yet not be fertile.
If I'm understanding your question correctly, when you say, "individuals" are you meaning animals?
Actually, I was wondering how humans (homo sapiens) evolved? Chap I think, pointed out that humans and chimps share 95% of DNA. And yet I don't know of any humans who think of mating with chimps as a possiblity. Not if they are mentally healthy, anyway.
truth dancer wrote:Generally speaking, a new species is created as a group of a particular species moves into a new environment and due to adaptation evolves in ways differently than the original group. Depending on the life form, it takes some time to completely evolve enough to become a separate species. The specific "point" where a couple could no longer be fertile would be determined by the type of species and the rate of evolution/adaptation.
At least that is how I understand it. :-)
That doesn't make sense to me. What is that point? What is that one little tiny mutaiton that would make the two individuals not fertile.
charity wrote:Thanks, the dude. But I really can't see how failure to interbreed works then. Wouldn't this require there to be at least one species of beings right now that was close to us genetically, but with which we humans could not produce offspring? Who or what would that be?
It might well have been Neantherthals, but they didn't survive, so it's hard to say. The existence of such species right now isn't necessary. The "very close to human but not quite" species may well have simply been out-competed and disappeared. With other species, there are in fact the very close cousin species still in existence.
Mormonism ceased being a compelling topic for me when I finally came to terms with its transformation from a personality cult into a combination of a real estate company, a SuperPac, and Westboro Baptist Church. - Kishkumen