What Homo Naledi Means for the Study of Human Evolution


(system) #1
The messiness of scientific discovery is a feature, not a bug.
This is a companion discussion topic for the original entry at https://biologos.org/blogs/guest/what-homo-naledi-means-for-the-study-of-human-evolution

(Brad Kramer) #2

The author (@Jimpithecus) is available to answer questions about this post.


(Phil) #3

Fascinating stuff. Thanks for posting. As it intersects theology, it seems the primary question is when did we become image bearers, and is that the same as being fully human. Can you be part human or is it an all or none phenomenon?
These issues have been debated here at length, but from looking at Genesis, it appears that at some point in history, God made a specific intervention after which humanity became morally responsible.


(Albert Leo) #4

In past posts I have cited brain scan evidence showing that a person that retains less than 10% of his brain mass can still operate in modern society an live a moral life, IF somehow his brain had been “programmed” earlier in life. So it seems reasonable to speculate that if God chose to “intervene” with Homo naled, granting him a conscience,then a small brain size need not have been the limiting factor. Another favorable factor, bipedalism, which would have enabled manual dexterity also would seem to be in the realm of possibility and favor homanization. Could it be that vocalization was the ‘missing link’? Even IF an epigenetic brain’programming’ event occurred in a tiny fraction of the H.naled population, they would need to invent a spoken language to spread it widely so as to establish a burgeoning culture, a Great Leap Forward. Perhaps the ‘intervention’ had to await the time Homo sapiens larynx descended to allow the spoken Word.
Al Leo


#5

I have been reading Origins Reconsidered: In Search of What Makes Us Human by Richard E. Leakey and he addresses much of what you are saying. He said language developed over time from the first Homo species and it is not an all or nothing proposition. Bipedalism seems to be another common trait with the earliest Homo species. The book is a little dated, 1993, but interesting.


(Albert Leo) #6

Yes, Leakey’s book was the first that lit my fire to learn more of our Origins. If you have not already done so, you will want to read Tattersall’s “Becoming Human” & “Masters of the Planet”. Also de Duve’s “Genetics of Original Sin”.
Ciao,
Al Leo


(George Brooks) #7

Wow… I hate that title.


#8

To be clear, it doesn’t seem that what’s being presented here is that Homo naledi is an ancestor of Homo sapiens but rather that naledi is likely a continuing primitive species of the genus Homo that persisted until rather recently (ca. 300,000 to 200,000 years ago) and may have overlapped with sapiens (or at least the immediate predecessor to sapiens). In other words we should think of naledi as a sister species rather than a parent. That said, the question about whether naledi could have been endowed with a conscience, language, etc. with such a small brain capacity (somewhere between a chimp and a gorilla, it seems) seems to me to be a bit too speculative and unnecessary.


(Albert Leo) #9

Yeah, but as a Nobelist, he does have some important things to say. For instance, if we all inheret Adam’s Original Sin, how could that happen except through our genetic inheritance? Of course both he and I look at it quite differently, and he chose the title just to catch the reader’s attention. Worked, too.
Al Leo


(Albert Leo) #10

Since it is highly unlikely that archeologists will ever find evidence for a ‘high culture’ associated with H.naledi, it is almost certain they were NOT endowed with conscience. Nevertheless, it is interesting to speculate just how much of H. sapiens brain power was necessary to achieve that level. Were they the first; or did H. neanderthalis, H. ergaster, or H. denisovan achieve at least the rudiments of morality? Some very interesting science is preceded by speculation, and the interface between science and theology is likely to remain so.
Al Leo


#11

Thanks, Al. In no way do I wish to frown upon speculation per se, just speculation in the case of whether naledi possessed something approaching conscience and language (which seems, like you said, highly unlikely). I agree, however, that it’s well worth speculating that neanderthalensis was much more human-like in these regards, though I do remember reading somewhere that neanderthals might not have been able to distinguish the many different vowel sounds that we can due to the different shape of their palates. I’m not sure, however, what the current consensus is on that front.


(George Brooks) #12

@aleo

Haven’t you worked all this out with our Vatican friend on the “origin of original sin” thread?

You make genetic inheritance sound logical here… but how did a decision by Adam suddenly get converted into a genetic “hot zone” ?

Now, what you want to say is that Adam & Eve were genetically unable to avoid sin 100% of the time, I would accept that… because that would be consistent with the frail nature of biological life.

But I don’t think that’s what the Creationists think. Their scenario has at least two points of magic in it - - maybe even three!:

  1. God test’s a moral neophyte before Adam knows anything about good and evil > this is a “magical” notion.

  2. When Adam succumbs to sin (because he obviously doesn’t know any better - the Bible says so), it alters his genetics?

this is also a “magical” notion.

  1. And, because of this, vegetarian animals become meat-eaters < whoa, that’s Real Magic there!

  2. Finally, for the grand finale’, because of a change in the genetics of Adam & Eve, everyone starts to die.

Why would YEC’s think genetics are irrelevant … when so much magic can be created by genetics?!

Adam’s decision to


(James Kidder) #13

Consciousness is a peculiar thing. Does it take a conscious thought to create and control fire? In that case, Homo erectus was doing that over 500 thousand years ago. At the fossil site of Schoeningen, in Germany, there was evidence of division of labor, complex tool production, an organized site layout and other behavioral clues that we would associate with “modern” humans. Is this the same as conscience? Not hardly. But it takes complex thought to have a conscience, and it appears that these people had at least that.


(James Kidder) #14

As far as speech is concerned, we would need to know if the FoxP2 gene was present and that will not be possible. Given that there is still a raging debate about whether or not Neandertals had speech, it is pretty remote that we would be able to determine that in any preceding form.


(George Brooks) #15

I’m much less impressed with the question of “Consciousness of Self” than I am with the more important issue:
“Consciousness of Morality”.

I once saw a video of a herd of Zebra crowding together to get at a water source. Out of nowhere, one Zebra took issue with another jostling him … and in 2 or 3 swift motions, he had kicked the other Zebra’s head once or twice - - and quite severely. After a few moments, the physically rebuked Zebra collapsed… and died right there.

All the other Zebra paid little attention … as the murdering Zebra nonchalantly walked away from the crime scene.

Before morality became entrenched in the human psyche, how many scenes like this were played out in any hominid camp ? - - with the only repercussions being a primitive prosecution of a “blood feud” if any kinsmen of the victim were around to see the deed, in which nobody else in the camp took much interest in, except not to be enmeshed in its deadly grip!


(James Kidder) #16

The zebras sound like the Eloi from the time machine. Zebras tend to display very little in the way of complex thought. The archaeological site that I described was over 300,000 years old and yet showed the evidence of considerable complex behavioral patterns. Did they crack each other over the heads from time to time? Maybe, but even modern human groups do that. Morality is, perhaps, even more ephemeral then conscience. There are numerous examples of genocide in recent history. Do those who commit those acts have morality? Maybe, but it sure ain’t the same as ours…we hope.


(James Kidder) #17

What these dates really drive home is that the human family is extremely diverse, with many different branches, quite a few of them overlapping, chronologically. As I noted in an original draft of the post, it basically means that we are probably underestimating the number of species there are in the human fossil record. You are quite correct, though, in that this sheds no light on the origins of modern humans.

To me, one of the most interesting questions is how a species like this managed to coexist with other, more advanced species in the same general area. I get how H. floresiensis did so because it was living in its own island paradise until modern humans came and ruined the party. It is harder to figure this with H. naledi. It is not like the Neandertals of Western and Central Europe, who could interact with (and occasionally mate with) modern humans because they were broadly similar in appearance. Maybe H. naledi were just the “weird cousins on the other side of the hill.”


(James Kidder) #18

Yah, no kidding. :slight_smile:


(Darrel R Falk) #19

“To me, one of the most interesting questions is how a species like this managed to coexist with other, more advanced species in the same general area.”

@Jimpithecus I think you know more about this than me, but I wonder if we can easily become a little biased by thinking that just because members of “our” species had larger brains at this point, they would necessarily have been better adapted. Here is an example of what I mean. The population size of the ancestors to chimpanzees was five to ten times larger than the number of our ancestors throughout much of the history of the two groups of hominid species in Africa. (Location 966, Ancestors in our Genome by Eugene E. Harris). I’m not sure that in those early days of 200,000 to 300,000 years ago before the major cultural shift that likely occurred rather suddenly about 100 millennia later, “anatomically modern humans” would have been adaptively superior. Ian Tattersall in his book, The Strange Case of the Rickey Cossack (loc. 3787) puts it this way:

This new capacity was based on a long series of neural acquisitions that had doubtless boosted the information-processing capabilities of the hominid brain over an extended period of time. But it was only suddenly—very recently, and in one sole lineage—that basically ancient ways of dealing with information were overlain—and, significantly, not replaced wholesale—by a radically new cognitive mode. This new mode was not only ex aptively rather than ad aptively acquired, but its properties were emergent, unpredicted by anything that had gone before. In other words, the novel way of processing information had not evolved for anything. It had just appeared, and the biology that made it possible evidently lay unexploited for some time, lying fallow until its possessor actively discovered its new uses.

Something quite remarkable happened to “our” species and Tattersall as well as many other scholars suggest that it happened rather suddenly. Perhaps until then, our lineage was just one of several twigs on the hominin bush and it would not yet have been clear which lineage would ultimately become best adapted.


#20

I’ve wondering the same thing–how naledi managed to coexist alongside more intelligent species of Homo. Maybe they had managed to carve out a somewhat isolated niche. I’m looking forward to what further findings and analysis of current findings might bring to light.__