A few weeks ago, I wrote a short post titled, Adam and Eve still a possibility?, in which I drew readers’ attention to the work of geneticist Richard Buggs, Reader in Evolutionary Genomics at Queen Mary University of London, who thinks it’s still theoretically possible that the human race once passed through a short, sharp population bottleneck of just two individuals, followed by exponential population growth. Biologist Dennis Venema, professor of biology at Trinity Western University in Langley, British Columbia, has recently written a two-part reply to Buggs, titled, Adam, Eve and Population Genetics: A Reply to Dr. Richard Buggs (Part 1) and A Reply to Dr. Richard Buggs (Part 2). But in a comment in response to a query of mine, Professor Venema conceded that at the present time, science cannot rule out Dr. Ann Gauger’s hypothesis that there was a severe bottleneck around two million years ago, with the emergence of Homo erectus, whom she identifies as the first true human being. When I pressed Professor Venema, saying, “In plain English, what you’re saying is that science can’t rule out an original couple, if they lived more than 1 million years ago,” he replied:
I guess it depends on how reliable you think PSMC methods are as they approach this time frame. The data looks smooth to me out to around 1.5 MYA or so, plus or minus, but the method loses its power as you go back further and further.
In a recent email message, Dr. Gauger clarified her position on Adam and Eve:
I did not settle on an old age for Adam so that the population genetics would work out or because I was seeking to prove two progenitors. It was because I could not understand why God would create Homo species so close to us and not be part of us, and because of morphology. I find species definitions to be tricky things, and sometimes they are assigned because of an agenda. H ergaster and H habilis are disputed for example. But for me Turkana boy is clearly human.
So I arrived at an early date because paleontology. I am aware of arguments for 200k (first modern skeleton), 70 k (Blombos cave, migration out of Africa), or 20-10k to match Genesis.) We will see if any of these dates, as well as the older one, can accommodate a unique origin based on AFS, LD, and several other pop gen statistics. Feel free to pass this on.
Dr. Gauger has adduced evidence that Homo erectus and Homo ergaster (African Homo erectus) were rational beings, who were capable of foresight: they transported tools over distances of 12-13 kilometers, compared to distances of just tens or hundreds of meters for Australopithecus and early Homo (see here). In addition, there is evidence (see also here) that Homo ergaster was able to tame fire as far back as 1,000,000 years ago, and perhaps use it to cook meat as well, although Wil Roebroeks of Leiden University in the Netherlands and Paola Villa, a curator at the University of Colorado Museum of Natural History in the U.S., cautions that we don’t have evidence of regular fire use going back any further than 400,000 years ago. Finally, excavations at the South African site of Kathu Pan suggest that Homo ergaster had a sense of aesthetics. As Dr. Gauger describes it:
…[T]he site has yielded what is termed, the ‘Master Hand-Axe’ which dates to approximately 750 000 BP rendering it the oldest artifact which is indisputably aesthetic i.e. worked for beauty and symmetry, perfectly oriented, and worked considerably beyond the functional requirements of the hand-axe, which could have been achieved with half or fewer blows (see Figure 4-2). The technology which produced it is known as the Acheulian, and the artifacts are thought to be made by Homo ergaster (Homo erectus in Africa), a diverse grouping of early humans commonly imagined as small-brained, small-jawed and robustly built, with heavy eyebrow ridges.
When I look at that master handaxe, I see aesthetics, painstaking care, and a joy in the materials. I see mind.
In a recent comment on Biologos, I expressed reservations about Dr. Gauger’s ancient Adam and Eve scenario:
However, if I were to identify the chief flaw of the ancient Adam and Eve scenario, it would be this: modern human behavior doesn’t appear until 100,000 years ago. Homo erectus may have had foresight (transporting tools over distances of more than 10 kilometers), the ability to control fire (although this is hotly disputed) and even a sense of aesthetics (judging from the elegance of some Acheulean tools), but it almost certainly lacked the capacity for art, religion and science. This means that in some ways it was less human than we are – which means that if we are to believe in Adam and Eve, we have to give up belief in human equality.
It is instructive to compare Homo erectus with modern-day tribes whose lifestyle has been described by some as “primitive.” Members of these tribes have relatively little trouble in adapting to the cognitive demands of civilization, some making the transition in as little as a generation. I doubt very much whether Homo erectus could have done that. And I also doubt whether anyone could have preached the Gospel to Homo erectus.
Finally, in a recent post on The Skeptical Zone, I marshaled evidence indicating that Homo erectus almost certainly lacked the use of language, and that even the Neandertals probably lacked it. What’s more, the human brain appears to have evolved specific traits in the lineage leading to Homo sapiens, which allowed our species to possess a full-blown theory of mind and imagine what others were thinking about them.
For her part, Dr. Gauger is not troubled by the fact that Homo erectus lacked our level of linguistic ability. And in a post on Biologos, she responded as follows to my concerns about the lack of symbolic culture in Homo erectus: “First of all, our full capacity for art, drama, philosophy, religion and language was not present 300,000 years ago. Nor was it present, it could be argued until the Egyptians, the early Greeks, and the Chinese had their cultural flowering.” I agree with Dr. Gauger that early Homo sapiens, who lived 300,000 years ago, lacked “our full capacity for art, drama, philosophy, religion and language.” I think that these abilities appeared 100,000 years ago, with the emergence of modern human behavior (see also here). Dr. Gauger argues that the long lag between the appearance of Homo sapiens and the emergence of behavioral modernity means that we shouldn’t consider Homo erectus subhuman because it didn’t behave in this way. I would argue, however, that the human brain did not stop evolving with the appearance of Homo sapiens. It may have subsequently acquired the traits which enabled us to use language and to possess a full-blown theory of mind.
So the long and the short of it is: Dr. Gauger’s model of a two-million-year-old Adam and Eve remains scientifically viable, but their minds would have been very different from ours. Personally, I wouldn’t call Homo erectus a true human being. The Neandertals I’m not so sure about, for reasons I’ve discussed previously.
I’ll just finish by mentioning the work of Dr. Joshua Swamidass, who is an assistant professor at Washington University in Saint Louis where he runs a computational biology group. In an article titled, A Genealogical Rapprochement on Adam?, he accepts “the genetic evidence in which it appears (1) our ancestors arise as a population, not a single couple, and that (2) we share ancestry with the great apes,” but also proposes that an individual named Adam “was created out of dust, and Eve out of his rib, less than 10,000 years ago in a divinely created garden where God might dwell with them, the first beings with opportunity to be in a relationship with Him.” After leaving the Garden, Adam and Eve’s offspring blended with that of their neighbors in the surrounding towns. “In this way, they became genealogical ancestors of all those in recorded history. Adam and Eve, here, are the single-couple progenitors of all mankind.” Of course, humans today have many genealogical ancestors, not just Adam and Eve. An article outlining Dr. Swamidass’s hypothesis will appear in the March 1, 2018 issue of PSCF (Perspectives on Science and Christian Faith). The important thing for readers to grasp is that genealogical ancestry is not genetic ancestry: “Though scientific discourse focuses on genetic ancestry, genealogical ancestry is germane to the theological claims about Adam.” Adam and Eve are ancestors of us all, because genealogical ancestry becomes universal in just a few thousand years. Dr. Swamidass contends that “Scripture and theology, at most, make claims about genealogical ancestry, but not genetic ancestry,” because when Scripture was written, people had no notion of what genes were. I’m not sure, however, that it’s that simple. The Bible appears to affirm that Adam and Eve were the only genealogical ancestors of the entire human race. As Acts 17:26 puts it: “From one man he made all the nations, that they should inhabit the whole earth; and he marked out their appointed times in history and the boundaries.” I’m also not sure exactly what new trait Adam and Eve were supposed to have possessed, under the scenario proposed by Dr. Swamidass, since he explicitly declares that even the human beings living outside Adam and Eve’s Graden were made in the image of God. It seems the only thing that was genuinely new about Adam and Eve was that they were spiritually fallen. But because genetic information is transmitted only unreliably, Dr. Swamidass argues that Adam and Eve, if they existed, “probably did not transmit DNA to all their descendants, nor did they transmit any identifiable DNA to any of their descendants.” He continues: “This means that Adam and Eve’s DNA is not how the Fall or original sin, if they exist, is transmitted to all of us.” At any rate, Dr. Swamidass’s article is a very stimulating read, which is sure to take the Adam and Eve debate in a new direction.
I’d now like to throw the discussion open to readers – especially those with a Christian background. If you had your druthers, which Adam and Eve would you pick? A two-million-year-old one, who was perhaps a lot dimmer than us, as proposed by Dr. Gauger? Or a Neolithic one, as proposed by Dr. Swamidass, who interbred with other humans that were made in God’s image and likeness, and left descendants all over the globe? Or neither of the above?
I’ll leave you all with a concluding thought: “We are more different genetically from people living 5,000 years ago than they were different from Neanderthals,” according to John Hawks, a professor of anthropology at the University of Wisconsin-Madison. Many of the genetic mutations that have spread through the human population in the last few thousand years relate to “changes in the human diet brought on by the advent of agriculture, and resistance to epidemic diseases that became major killers after the growth of human civilizations.” Civilization seems to have been what’s changed us most. But how has it changed our brains? That I don’t know. Maybe someone can tell me. Over to you.
I don’t think I wil try that, no.
You don’t have any pets I guess?
Because women pass on heritable material as well, perhaps?
Perhaps or maybe your idea evolution is not complete. Or maybe we are just extremely lucky that irreducible complexity persists by accident sometimes
I going to tell you that there is no such thing as genetic isolation at least initially and if an IC structure is to arise and persist it must do so in that context
nope just the surviving descendants that reproduced and whose genetic legacy still persists.
Sure it could all it requires is a little “luck” and some Genghis Khan style seed spreading.
Evolution is riddled with stories of traits that became fixed simply because of historical accidents. At least that is how it appears in hindsight from the perspective of a Darwinist
peace
I have a couple of dogs. I love them very much. They are extremely intelligent
They are not human though
peace
Of course, No one is disputing that.
We are discussing how a particular trait became fixed in a mixed population and I simply would not want to rule any possibility out.
peace
It requires more than a little luck. In fact, it requires odds that are usually employed for arguing against blind evolutionary change. Not perceived as a problem now though, I suspect.
but they cannot love you back?
It is equally likely that being human is inherited matrilineally then?
Depends on how you define love.
They can love me like a Dog loves but not like a human loves.
Dog love is analogous to human love but not equivalent.
In some ways dog love is richer than human love in someways not as rich. If dog love was equivalent to human love it would be immoral to have them as pets but moral to have them as spouses.
I’m amazed that this is even an issue it seems so obvious to me.
Peace
Exactly!!!!! 😉
peace
Again I simply have no idea. We would need to know exactly what is being inherited before we could even venture a guess.
peace
I think now is a good time to summarize where I think we are in agreement and where we are not
1) We agree that Adam and Eve are not ruled out by modern genetics
2) We agree that what ever makes us human is likely to come from a set of multifaceted irreducibly complex factors.
at the same time
3) You think that it’s more likely that this irreducibly complex arraignment arose more than once than that it arose one time and persisted until it became fixed and universal in our lineage. While I think both scenarios are equally unlikely
Does that about cover it?
peace
From the perspective of ID the fact that humanity is unlikely is a feature and not a bug. ;-). We are here despite the odds because that was the plan all along.
On the other hand
From the perspective of Darwinism the existence of humans despite the overwhelming odds against us is something that needs to be explained. Unless we want to chalk it up as just another lucky accident.
peace
The relevant probability is 1.
In more detail, the proper question is: What is the conditional probablity that human exist, given the condition that humans exist? And that probability is 1.
In other words “stuff happens” and whatever happened simply had to happen no matter how unlikely it seems.
Nothing to see here, we can chalk it up to just another lucky accident
did you get that Corneel? 😉
peace
No, that’s a complete misrepresentation of what I said.
We observe that X happened. Then the important probability is the condition probability that X happened, given that we observed it.
It’s the weak anthropic principle.
right
We observe that X (ie stuff) happened.
IOW
If X (ie stuff) happened then X (ie stuff) had to happen—- because the probability that X(ie stuff) happened is 1
just as I said
peace
The week anthropic principle is employed to explain the existence of unlikely things that are required for us to exist.
“If X (ie stuff) is necessary for us to exist and we exist then X (ie stuff) must exist.”
You don’t often see it employed to explain our actual existence itself.
“If we exist then we had to exist because after all…… we exist”
peace
Yep.
No, I believe this change happened gradually in a large population rather than suddenly switching the lights on in one couple.
Anyway, I will be switching off myself for the holidays. Have a Merry Christmas Fifth.
I know the answer to that one:
from Terry Pratchett, who is sadly no longer among us.
I see.
So what would you call all the organisms that were only part human in the interim? Would they be entitled to some but not all human rights? Would it be considered murder to kill an Australopithecus? What about Pan troglodytes?
Are certain populations in the genus homo existing today possibly more or less human than others. If not why not? How could you say?
Since the we can’t define humans genetically and you rule out defining them by decent from A&E what are the defining characteristics of human?
IQ? Skin pigment perhaps?
For me Adam and Eve are important because they form the boundary between “someones” and “somethings”. I’d really like you to explain how you can make that distinction given your scenario,
You too,
I enjoyed the conversation, as usual around here I think it’s winding down just when it might be getting good 😉
peace
I don’t think you got Neil’s unintentional point
It’s not that the universe was made for humanity’s existence but that humanity’s existence was made for humanity’s existence
peace
To paraphrase Descartes, we exist therefore we exist.
In this context a better way to put it would be
We exist therefore we had to exist because the probability we exist is one.
😉
peace
Neil’s attempted use of the weak anthropic principle in this context is something like this
Imagine I won the lottery today and tomorrow I expressed my amazement at the good fortune that I won despite the fact that I have never purchased a lottery ticket and playing the lottery is illegal in my state.
Now imagine Neil Rickert stops me and says
“Your wining the lottery yesterday is not the result of good fortune at all because you are a lottery winner so the probability that you won the lottery is of course one.”
To which I would of course reply
“LOL” 😉
peace
Depends on when one calculates the probability before or after the event.
Of course it does.
Corneel and I were looking at the probability that the unlikely IC complex that is humanity arrived once and persisted verses sorta arriving multiple times incompletely (I guess) and fading and then finally persisting for some reason.
To point out that once it arrived it’s probability is one is irrelevant and just silly
That is what the lottery example and the LOL were about
peace
I just found this this morning
https://cosmosmagazine.com/biology/complex-speech-in-humans-is-a-recent-development
If what makes us human is more than just our genes I would expect something like this to be true.
If we assume a 10,000 individual bottle neck the epigenetic change that separated us from “the others” could very well occur in the offspring of just one couple
quote:
Researchers now believe that for spoken language to become a successful and stable evolutionary strategy, humans must first have developed both full symbolic culture and extremely high levels of interpersonal trust.
end quote:
peace
*clicks link*
Uh, right. How did they get to that conclusion?
Can you explain to me, fifth?
This seems appropriate here:
Corneel,
Perhaps that is as explicit as we can ever possibly get 😉
peace
Just read it this morning and it jumped out at me.
I’ll take some time and get back to you
peace
Hi fifthmonarchyman、
Happy New Year. Thanks very much for the article you linked to, which adds to the growing volume of evidence that the Neandertals lacked what we would call language:
Complex speech in humans is a recent development by Stephen Fleischfresser (Cosmos, March 17, 2017):
Here are a couple of quotes from the paper, Recent Regulatory Changes Shaped Human Facial and Vocal Anatomy by David Gokhman et al. (bioRxiv, doi: http://dx.doi.org/10.1101/106955, February 8, 2017):
Here’s an excerpt from a report by Ann Gibbons in Science magazine (October 23, 2017), on the 2017 annual meeting of The American Society of Human Genetics, where scientists discussed the significance of Neandertal genes:
Robert Berwick, Marc Hauser and Ian Tattersall, in an article titled, Neanderthal language? Just-so stories take center stage (Frontiers in Psychology, September 24, 2013, https://doi.org/10.3389/fpsyg.2013.00671) argue that (i) “hominids can be smart without implying modern cognition”; (ii) “smart does not necessarily mean that Neanderthals had the competence for language or the capacity to externalize it in speech”; (iii) the earliest unambiguous evidence for symbolic communication dates from less than 100,000 years ago; and (iv) although they may have had the same FOXP2 genes as we do, “[n]either Neanderthals nor Denisovans possessed human variants of other putatively ‘language-related’ alleles such as CNTAP2, ASPM, and MCPH1.”
The evidence appears to be overwhelming that Neandertals did not possess anything like modern human speech. The next question that needs to be addressed is: exactly when did modern humans acquire it? 300,000 years ago, with the dawn of modern Homo sapiens, or 100,000 years ago, with the dawn of modern human behavior? For the time being, I’d suggest the latter.
Oh, so you know how they got to that conclusion.
Please tell me how they inferred the evolution of vocalization and language evolution in modern humans from a handful of methylation changes in the proximity of SOX9, NFIX, ACAN and, hey look, a collagen gene.
I want to be able to do that too.
It seems so. If is turns out to be true the reasons why this is the case fascinates me
I found this quote to be especially interesting and fodder for some big speculation
quote:
for spoken language to become a successful and stable evolutionary strategy, humans must first have developed both full symbolic culture and extremely high levels of interpersonal trust.
end quote:
The necessary presence of something like an extremely high level of interpersonal trust to me suggests a special bond was necessary
Something approaching covenant.
quote:
Then the man said, “This at last is bone of my bones and flesh of my flesh; she shall be called Woman, because she was taken out of Man.” Therefore a man shall leave his father and his mother and hold fast to his wife, and they shall become one flesh.
(Gen 2:23-24)
end quote:
I’ll now step back to make room for the exploding heads
😉
peace
Overwhelming? Is it now?
Wasn’t the Berwick article a critical commentary on another paper, that establishes a diametrically opposite conclusion? So how exactly did you rule out that modern speech predates the appearance of anatomically modern humans? Perhaps you can deduce the evolution of language use from the expression of the FOXP2 gene. I note that Berwick and colleagues have a different opinion on that in the very commentary you cite:
and :
That goes both ways.
science does not rule out things. It’s possible that donkeys can talk they just don’t do it when we are around.
What we apparently did is find epigenetic mechanisms associated with speech that are present in us but not in “archaic humans”. That is all
peace
Then why is Vincent crowing about he “overwhelming evidence” that Neandertals did not possess anything like modern human speech (and you seemingly concurring)? What happened to the not wanting to rule any possibility out, I wonder?
Very well then, So how did you reach that conclusion? What does the speech epigenotype look like?
For me it comes down to the total lack of archeological evidence for symbolic thought like cave paintings for archaic humans and the arguments made by Steven pinker in The Language Instinct.
From reading the article. Here is part of the abstract,
quote:
we use>60 DNA methylation maps of different human groups, both present-day and ancient, as well as six chimpanzee maps, to detect regulatory changes that emerged specifically in modern humans. We show that genes affecting vocalization and facial features went through particularly extensive changes in methylation.Especially,we identify expansive changes in a network of genes regulating skeletal development (SOX9,ACAN and COL2A1), and in NFIX, which controls facial projection and voice box(larynx) development. We propose that these changes might have played a key role in shaping the human face, and in forming the human vocal tract configuration that is considered optimal for speech.
end quote:
peace
Anthropology is not my strong point, but I believe there is at least some evidence for “symbolic behavior” among Neanderthals, including engravings, ornaments, and pigments. I am not familiar with the book. What are those arguments?
I read the article as well. They found genes associated with modern-human specific methylation changes to be enriched for genes that result in disease phenotypes in the facial region, pelvis and the larynx. The “optimal for speech” part is an intriguing suggestion, but mere speculation. Now, I don’t know about you guys. But personally I would be a bit more hesitant to count this as support that Neandertals lacked what we would call language.
I get it,
I would say that the reason you are so “cautious” is precisely because you don’t hold to the idea of A&E.
As I’ve said repeatedly A&E give you a place to draw a boundary between humans and others between someones and somethings.
If you don’t have a boundary I would expect you to be forever seeing hints that maybe this or that organism also qualifies as human in some sense.
It would take an entire thread to detail them adequately .
Some of the high points were about how all human languages can be traced to a single point of origin and the importance of the critical period theory in language acquisition.
peace
Methylation of DNA is not known to last more than a few generations — unless DNA sequence changes occur that change which sites are prone to getting methylated. The differences between human and chimp in methylation therefore are most likely due to DNA sequence differences between them. So just observing consistently different methylation patterns in the two species does not show that there can be stable methylation changes in the absence of the appropriate changes in DNA sequences.
Yes, the differences in DNA methylation probably just reflect differences in transcriptional activity of nearby genes, rather than causing them.
The problem with Fifth is not that he denies that differences in methylation status reflect DNA sequence changes, but that he uses an idiosyncratic terminology in which only DNA sequence changes in coding regions qualify as “genetic” and the rest is “epigenetic”, including changes in regulatory DNA.
You can see why I have abandoned this particular line of argumentation 🙂
Of course there is also C.H. Waddington’s original usage of the word “epigenetic”, which more or less just means “developmental”. But it has been superseded these days by a meaning which restricts it to changes in the chromosomes. And expanded a bit to include changes that get inherited.
And then there’s FMM’s usage …
There are two kinds of methylation patterns that are “inherited”. The ones that are acquired (qausi lamarkian) and the ones that aren’t said to be inherited but actually are via a mechanisms not completely understood such as the methylation marks that are put on some somatic cells but not others.
Example:
The methylation marks are erased and then put back, on various somatic cells in various stages of development:
Let’s clarify: “inherited” doesn’t mean inheritance in cell lines within individuals but inheritance across generations of individuals. If it isn’t in the egg or sperm, it isn’t inherited. If it’s recreated during development, what’s inherited is the thing that causes the methylation pattern to be recreated. Bet that thing is some particular set of DNA sequences. That is, methylation differences between populations must be inherited as DNA differences between populations. What’s your argument to the contrary?
Agreed.
I bet the other way. We’ll see.
Yes,
But if we don’t yet know the thing that causes the methylation pattern to be recreated then the methylation pattern can serve as a proxy marker of inheritance. Right??
That would be my bet as well, not for any specific theological or philosophical reason but just because I think that there is a lot more going on than “DNA sequences”
It’s this sort of thing that makes discovery interesting.
peace
This thread tastes like dino-chicken.