This is a companion discussion topic for the original entry at https://biologos.org/blogs/guest/did-the-last-common-ancestor-to-apes-and-humans-live-in-europe
In hindsight, “errors” and “mutations” are pretty much the same thing.
What an odd little article!
When I read this, I just closed up the computer screen.
"How did they get to Africa?: “But if the earliest members of our line did live in this area of southern Europe, how did they get to Africa?”
I think the more likely implication is what drove an African population beyond the fringe of Africa!
“Living in Europe” is easy. But originating in Europe? This seems most unlikely …
With all due respect I think this line is very important: “Where the human/great ape split took place is, in the grand evolutionary scheme of things, a fairly minor point.” Of course if one’s specialty is the question of where and when the last common ancestor lived, then this is exciting. But I think its important to clarify a couple of things, that I am sure the author agrees with, but didnt mention. This finding says nothing about the African origin of modern humans, which is now well established, and also says nothing to dispute the common origin of all humans (H. Sapiens) in Africa.
I am also aware that it has become the norm to refer to early hominins as “humans” (as in "human/great ape split), but I feel that can lead to confusion, especially in a theological context. While there may be no sharp distinctions among the spectra of hominins from Australopithicus to us, calling the former “humans” is at best misleading, when dealing with modern human characteristics. Just my POV, which I know is not very popular.
I admit to feeling a bit confused. The last common ancestor to great apes and humans would also have to be ancestral to gorillas and orangutans so would be quite a bit earlier than this footstep (as in many millions of years). What the articles seems to be talking about is the last common ancestor to humans and chimpanzees. Also to say that humans had likely split from chimpanzees in Europe we would have to have evidence either of chimpanzee ancestors (post split) also in Europe or of a common ancestor (but too far before the split) also in Europe. Otherwise evidence of human ancestors relatively shortly post-split in Europe would more likely indicate a fairly successful variety that spread widely from wherever the split took place (much like modern humans were to do).
Agree with you that the article is sort of cobbled together and does not make a coherent case. Your POV makes more sense.
What I am saying is that, in combination with the dental evidence from around 7.0, there is at least the possibility that we are looking in the wrong place for the LCA. The footprints are evidence of hominins walking around in Greece pretty much coeval with the earliest fossil evidence we have for hominins, at 6 million years ago, in Africa. Remember, the genetics indicates that the LCA may have lived over 10 million years ago. We just don’t know where that was. The footprints establish a much larger area in which to look. This is especially true if the dental evidence holds up because then you really do have the earliest evidence of hominin traits at 7 million. Just not in Africa. I have read enough about Sahelanthropus to think that we should not look there.
As far as Orangutans are concerned, they split some 20-25 million years ago, when the world was dominated by the “age of the apes.” The orangs are the descendants of apes that lived in that region.
Hominids came out of Africa in waves… separated by vast chunks of time.
How do some footprints in Europe convince anyone that hominid evolution was was fast enough in Europe that all subsequent waves out of Africa were defeated or pushed back?
Maybe the LCA was somewhere in north Africa and waves moved north AND south. This would explain the remains in both Europe and Africa. North Africa was lush and verdant at this point. Maybe the south was where hominin evolution really took hold. Who knows. I just think that there is no a priori reason to rule out the idea that the LCA was somewhere in the circum-Mediterranean.
One can’t rule it out yet and no one is that the last common ancestor of humans and chimpanzees (not all apes) took place outside of Africa. It just seems less likely.
I would also note that there has been a bias to trying to find human ancestors in Europe (or particular parts of Europe). The Piltdown hoax wouldn’t have worked as well if so many English hadn’t wanted remote human ancestors to be English.
There is no a priori reason. That’s for sure.
But a foot print makes for pretty weak reasoning of any kind.
It is not just the footprint. It is also the dental evidence. Nobody is saying that this is a smoking gun. They are simply raising the possibility. As David Begun said, there is no a priori reason for the LCA to be in Africa. There are lots of Miocene apes in southern Europe and in Egypt. This notion that everything had to come out of Africa is sort of the opposite of Eurocentrism. I am not saying it did, but what if the LCA originated somewhere in Southern Europe or in the Mediterranean area and it’s descendants are those hominins that we find in north Africa. With the exception of Orrorin, everything early is in north Africa. All of the later hominins are in East Africa and south Africa.
And no, I don’t think this is a case of Flipperpithecus.
Thank you, Jim for this interesting summary. I think you’ve been justifiably cautious throughout. The authors of the original article stress that the structural data on the tooth is unlikely to be due to convergent evolution although they end their paper with the following statement: “we acknowledge that the known sample of fossil hominin (tooth) root configurations is too small for definitive conclusions.” So, you are right to be cautious, as indeed they are in the paper itself. They become, it seems to me, a little more freewheeling in their post-publication discussion with the press where they are no longer subject to peer-review. In fact I am surprised to see the press only interviewing the authors. Usually, by my experience, journalists make an effort to get the impression of those with no vested interest in the importance of the findings. So caution is surely advised especially when the conclusions are based upon a single mandible from one individual and a single tooth from another. The footprints are interesting, but as those authors admit, they could be a case of convergent ape evolution — not on the hominin lineage at all. Your caution on both counts is well-placed.
I’d like to clarify a couple of points addressed here that stem from DNA sequencing. Although, it is true that the protein coding portion of the chimpanzee and human genomes are 99.4 percent identical, the two genomes as a whole are considerably more different from each other. At the level of individual coding units (bases), they differ at the level of 1.23 percent (as Venema shows in the article you cited). This corresponds to a difference of tens of million of sites (bases).
I would also like to emphasize what appears to me to be fairly wide-spread consensus of what the DNA sequencing data has to say about the timing of the last common ancestor of chimpanzees and humans (5.5-7 million years ago [MYA]), gorillas and humans (8.5 to 12 MYA), and orangutans and humans (12-16 MYA). I have confirmed this through consulting several publications and they all roughly agree with these estimates. (I realize that the Science journalist Annne Gibbons wrote in 2012 that there was data suggesting up to 13 MYA for chimp/human, but I can’t find any source that confirms that.) Here are the references I consulted: Nature 483:169 (2012), Nature 469:529 (2011), ILAR Journal 54:82 (2013).
Again, thanks for a thought-provoking article and for beginning it with a question mark. It will be interesting to see if other investigations are able to confirm these preliminary findings.
Thank you, Darrel. I fully recognize that this ichnofossil evidence is scant (even more so now that some vandalism has taken place) and I regard the article in the same cautious way the authors meant. In a sense, the article serves as a jumping-off point for future research, rather than any sort of definitive conclusion. As I noted, this is evidence of hominin activity in an area that no one has thought to look at. If, for nothing else, this spurs more research in this region, then the article will have served its purpose, in some ways. Maybe more will be discovered, maybe not. But now, at least people are looking.
As to some of the finer notes of your post, I should have clarified that the 99.4% number is what you get when you restrict to the protein-coding regions of the two genomes. I hope that I have not misread Dr. Venema on this point. As for the divergence times: from the Langergraber et al. article:
“For example, we estimate the bonobo and chimpanzee split time at 1.5–2.6 million years, whereas previous estimates put it at less than 1 million years. We estimate the split time between the human and chimpanzee lineages at between 7 and 13 million years, whereas previous estimates range from 4 to 6 million years. We estimate the split between the gorilla lineage and the lineage leading to humans, chimpanzees, and bonobos at 8–19 million years, whereas previous estimates range between 6 and 7 million years.”
Is it as far back as thirteen million years? That seems early to me, simply because of what we find from the morphology of Ar. ramidus and Ar. kadabba, both of which seem very ape-like, despite the hominin characteristics.
What seems more likely to me is that the circum-Mediterranean region, extending to north Africa saw a radiation of late Miocene forms, some of whom reflect adaptations toward a more modern condition.
I am looking forward to the next set of discoveries as we get closer to answering this great question.
Sorry Jim, you are correct. I had missed the PNAS article you cite, which specifically addresses the issue through DNA sequencing data alone—setting aside the fossil data. This results in a broader range. The authors of the papers I cited include fossil data in their calculations and the way that was done gives the appearance of narrowing the range. You are right to stress the uncertainty.