Could modern apes, chimps evolve into "humans" ?

[Crossroads Inc.]

Let us pose the following thought exercise.

Lets say you had access to a Time Machine and an alternate Earth on which to experiment on. If you took modern Chimps or Bonobos and put them in a world free of Humans, at some point would the follow our own evolutionary path? Conversely if you took them back in time and put them into the same era in which our earliest ancestors where gettign started, would they, again follow a similar evolutionary path?

[Simon_Jester]

It is far from certain that they would, but they probably could.

To actually make it happen you'd basically need deliberate selective breeding. First you'd need to put them in an environment where they had to come down out of the trees like we did, and where it made biological sense for them to evolve things like walking on their hind legs and more tool use and social skills. If the conditions were right and you waited long enough you'd probably get a lot of speciation, and there'd be a pretty good chance of getting recognizably intelligent 'hominids' out of the process. Parallel evolution in similar environments is pretty common, after all.

[Ziggy Stardust]

It's hard to say, really, and it depends on how close to "humans" you want them to be. In the right conditions, it would certainly be possible for them to evolve into a hominid-like species with our level of intelligence, though there social structures and physical attributes could, and likely would, be radically different. But, generally speaking, if the conditions are right it would be a possibility. The real question is whether or not it would be possible under ANY conditions, or only under very specific ones. We don't know enough about early hominids to know for sure how/why they diverged in the way they did, and we also don't know enough about the evolutionary development of higher cognitive functions to know if the conditions chimpanzees/bonobos currently live in would allow for the types of selection necessary to achieve our level of intelligence.

For example, humans have 3 muscles in our hands that chimpanzees lack, as well as thicker/broader metacarpals, which allow for a dexterity and precision in our hands that they do not. We know that chimpanzees can use tools (often in sophisticated manners), but we don't know if this basic physiological difference would preclude them from developing the type of tool use early hominids did.

Also, it is worth noting that chimpanzees have had just as much time as humans, evolutionarily, to get where they are. The divergence between Homo and Pan was around ~6 million years ago, IIRC. Why did our two lineages develop so differently? Tough question to answer.

[Junghalli]

To actually make it happen you'd basically need deliberate selective breeding. First you'd need to put them in an environment where they had to come down out of the trees like we did, and where it made biological sense for them to evolve things like walking on their hind legs and more tool use and social skills.

Perhaps leaving them where they are in a world free of humans would do it. IIRC, the same long-term forces that likely pushed our ancestors onto the grasslands (the growing and shrinking of the African tropical forests with the ice ages) is still operating; left on their own in an empty world some chimps might eventually get pushed down the same general evolutionary pathway that we did.

[MrDakka]

Perhaps leaving them where they are in a world free of humans would do it. IIRC, the same long-term forces that likely pushed our ancestors onto the grasslands (the growing and shrinking of the African tropical forests with the ice ages) is still operating; left on their own in an empty world some chimps might eventually get pushed down the same general evolutionary pathway that we did.

Wouldn't using selective breeding like Simon Jester suggested and/or more pressing evolutionary forces help speed up their evolution?

[Skgoa]

Of course but the way I understand the OP, that's not the point. I.e. it's pretty unlikely that wolves would ever evolve on their own into those tiny dogs middle-aged women like. But apes could very well develop into "humans" on their own.

[LaCroix]

The more pressing question is - given their limited spread (they are endangered, aren't they), would their genetic diversity be a positive or negative factor?

Also - what would be the other contender? Which other species' do have a shot at the new race? Dolphin? Octopus? Some kind of Bird?

My guess is that if cats (especially if they develop an opposable thumb), they might be the best guess - predators, quite intelligent already, already use their front paws for grabbing things and lazy/curious enough that they would use tool if it'd provide a shortcut...

[Ziggy Stardust]

Perhaps leaving them where they are in a world free of humans would do it. IIRC, the same long-term forces that likely pushed our ancestors onto the grasslands (the growing and shrinking of the African tropical forests with the ice ages) is still operating; left on their own in an empty world some chimps might eventually get pushed down the same general evolutionary pathway that we did.

Why would they leave for the grasslands? It isn't "just" that our ancestors were pushed onto the grasslands, it is that they underwent selective pressures that allowed for the development of certain adaptations that allowed them to survive on the grasslands. That is, it is very unlikely for a gibbon or other highly specialized primate to make that sort of move a la early hominids, as evolutionary speaking it is a lot harder to regain lost traits than to realize new ones. Modern chimpanzees aren't quite as specialized as gibbons or bonobos, the question is are they far enough down an evolutionary bottleneck to allow for the dramatic shift in physiology and behavior that would necessarily be entailed in such a move?

[Junghalli]

Modern chimpanzees aren't quite as specialized as gibbons or bonobos, the question is are they far enough down an evolutionary bottleneck to allow for the dramatic shift in physiology and behavior that would necessarily be entailed in such a move?

Is that answerable without knowing more about what the last common ancestor of humans and chimps was like than we do now?

[Ziggy Stardust]

Is that answerable without knowing more about what the last common ancestor of humans and chimps was like than we do now?

Technically, yes, I was mostly throwing it out there as a discussion point. While we do not know a whole lot about the chimpanzee-human last common ancestor in specific, we do know a lot about the way other extant species relate to each other and their LCA. For a very extreme example, elephants and sirenians (manatees, etc.) are the closest living relatives of some LCA, but have diverged wildly in their pertinent characteristics, such that it would be incredibly unlikely for one to move into a similar niche as the other at this point in their evolutionary development. They are just so wildly different.

Now, obviously, humans and chimpanzees have not diverged quite as wildly as this. But, as I said, that is the extreme example. The question we have to think about is what traits did proto-humans (Australopithecus, Ardipithecus, etc.) have that enabled the divergence from the LCA with chimps, and what traits do chimps have that enabled this divergence? I mentioned in my earlier post the difference in the structure of our hands ... chimps, while they do have remarkable dexterity, are physically structured in such a way that they cannot manipulate things as powerfully as we can. However, there are also issues like the structure of the arms, legs, and the form of the pelvis. The shape and structure of the feet and toes is incredible important, as well ... the degree to which the hallux abducts or adducts is a primary factor in determining the speed and angle of a bipedal organisms gate. Chimpanzees have an abducted hallux, which is what allows them to use their feet almost like hands, but which also exerts different selection pressures on the structure of their feet than that which would allow for an easy transition to full bipedalism. If anything, chimps are currently being selected towards a more strictly quadripedal life cycle. (Here are some great excerpts from a book on the evolution of the human gait. Fascinating topic).

[Captain Seafort]

The more pressing question is - given their limited spread (they are endangered, aren't they), would their genetic diversity be a positive or negative factor?

We've been far more endangered at times than chimps are currently - their population is well over ten times that of post-Toba homo sapiens.

[Ziggy Stardust]

We've been far more endangered at times than chimps are currently - their population is well over ten times that of post-Toba homo sapiens.

To nitpick, the bottleneck theory of the Toba catastrophe postulates, IIRC, that there were somewhere between 1,000 and 10,000 breeding pairs of humans whose genetic information survived to modern humanity, but that the actual population at the time is generally unknowable. That is, the population could have been 10 times that, but other genetic lineages died out somewhere in the last 70,000 years.

[ArmorPierce]

We've been far more endangered at times than chimps are currently - their population is well over ten times that of post-Toba homo sapiens.

To nitpick, the bottleneck theory of the Toba catastrophe postulates, IIRC, that there were somewhere between 1,000 and 10,000 breeding pairs of humans whose genetic information survived to modern humanity, but that the actual population at the time is generally unknowable. That is, the population could have been 10 times that, but other genetic lineages died out somewhere in the last 70,000 years.

Either way, Chimpanzees actually have greater genetic diversity than modern man.

[Ziggy Stardust]

Either way, Chimpanzees actually have greater genetic diversity than modern man.

Yeah, I was just being really nit-picky.

In fact, the genetic diversity among chimpanzees is actually far greater than what you would expect if you were only accounting for a human genetic bottleneck. The divergence among two populations living on opposite sides of the Sanaga River is greater than that between humans from different continents.

[Anguirus]

No.

We share a common ancestor with chimps. Recent finds have thrown into question the idea, which was more a brainbug than anything else, that that common ancestor resembled chimps any more than it resembled humans.

[ArmorPierce]

@Ziggy, yeah I realize that you were just nitpicking but your post seemed the best one to quote for a followup.

No.

We share a common ancestor with chimps. Recent finds have thrown into question the idea, which was more a brainbug than anything else, that that common ancestor resembled chimps any more than it resembled humans.

Yup. More likely our last common ancestor resembled more a gibbon (my personal theory) which spends more time in the trees and less time on ground than either chimp or human. Chimpanzee and human mode of walking were merely two different possible adaptations to terrestrial living. Gibbons form. Of walking actually resembles more that of a human than a chimpanzee imo. It walks upright while dragging its hands on the floor since its arms are so long

[dworkin]

Short answer no.

Long answer. No. Chimps have gone their own merry way in the five to six million years since our ancestors and theirs were the same individuals. A possible path to human equivalent intelligence would go on from their current point and end at a divergent result. How divergent would depend on how long it took.

That's not to say a Pans sapien wouldn't be recognisable and have signs of parallel or convergent evolution but there would be nothing human about them.