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The impression I got from a recent PBS Eons video on the non-existing missing link[0] is that interbreeding happened all the time and that a very realistic poss

The impression I got from a recent PBS Eons video on the non-existing missing link[0] is that interbreeding happened all the time and that a very realistic possibility for the answer is "most, possibly all of them". [0] https://www.youtube.com/watch?v=pwW40Dj5Sro https://www.youtube.com/watch?v=pwW40Dj5Sro

dalbasal 7y ago
At >4mybp, this species may have been genetically close enough to interbreed with chimp ancestors. If it overlapped with afarensis and other australopithecines, hybridisation almost certainly would have been possible. These guys were as closely related (at least in the earliest periods) to eachother as we were to Neanderthals, denisovans and the other undiscovered species who we know our ancestors mixed with. Homo habilis started its career as an australapithicine, and could probably reproduce with "non-homo" species. A lot of the classification only makes sense after the fact. If habilis hadn't produced the homo genus, it would just be an australapithicine, and we wouldn't consider it separate from them.
- Robotbeat 7y ago
  To what extent does number of chromosomes matter, here? I'm still confused about how species with different number of chromosomes can successfully interbreed without major problems in their offspring and thus I am still confused about the process of how a species can change its number of chromosomes (since the genetic problems that might occur with such crossbreeding would not likely be terribly helpful in survival). Is there any really good explanation for this that someone can point me to?
  - dalbasal 7y ago
    Having a different number of chromosomes is a hurdle, but not an absolute barrier to offspring reproductive viability. It's not necessarily an issue for animal health. Horses & donkeys have a different number of chromosomes. They're also separated by an estimated 4m years of evolution, which is around the rule of thumb limit for large mammal hybridization so it makes sense that they're borderline hybridizable. They have shorter generations than us apes. Anyway, mules are healthy. No survival issues. They are mostly infertile, but not 100% of the time.
mirimir 7y ago
Yes, if they overlapped in time and location, they probably interbred. With everything that ~looked like them. Or at least tried to. As we're seeing with Neandertals and contemporaries.
duxup 7y ago
A PBS show was my first though too. It seems pretty clear that rather than various "species" and isolated lines that there is all sort of mingling of the lines and trees, and to some extent you can expect it happened in places that you otherwise might not have assumed before.
Balgair 7y ago
PBS Eons is an amazing show! Their other episodes on Purple Earth, the Devil Hogs, etc are great! I love my boy Steve!

dalbasal 7y ago

At >4mybp, this species may have been genetically close enough to interbreed with chimp ancestors. If it overlapped with afarensis and other australopithecines, hybridisation almost certainly would have been possible. These guys were as closely related (at least in the earliest periods) to eachother as we were to Neanderthals, denisovans and the other undiscovered species who we know our ancestors mixed with. Homo habilis started its career as an australapithicine, and could probably reproduce with "non-homo" species. A lot of the classification only makes sense after the fact. If habilis hadn't produced the homo genus, it would just be an australapithicine, and we wouldn't consider it separate from them.

Robotbeat 7y ago
To what extent does number of chromosomes matter, here? I'm still confused about how species with different number of chromosomes can successfully interbreed without major problems in their offspring and thus I am still confused about the process of how a species can change its number of chromosomes (since the genetic problems that might occur with such crossbreeding would not likely be terribly helpful in survival). Is there any really good explanation for this that someone can point me to?
- dalbasal 7y ago
  Having a different number of chromosomes is a hurdle, but not an absolute barrier to offspring reproductive viability. It's not necessarily an issue for animal health. Horses & donkeys have a different number of chromosomes. They're also separated by an estimated 4m years of evolution, which is around the rule of thumb limit for large mammal hybridization so it makes sense that they're borderline hybridizable. They have shorter generations than us apes. Anyway, mules are healthy. No survival issues. They are mostly infertile, but not 100% of the time.

mirimir 7y ago

Yes, if they overlapped in time and location, they probably interbred. With everything that ~looked like them. Or at least tried to. As we're seeing with Neandertals and contemporaries.

duxup 7y ago

A PBS show was my first though too. It seems pretty clear that rather than various "species" and isolated lines that there is all sort of mingling of the lines and trees, and to some extent you can expect it happened in places that you otherwise might not have assumed before.

Balgair 7y ago

PBS Eons is an amazing show! Their other episodes on Purple Earth, the Devil Hogs, etc are great! I love my boy Steve!