My Idea Of How Apes Turned Into Humans

[write4u]

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Evolute said: Nice post with some good analytics. But with all due respect, Human chromosome fusion of the Ape's 2a and 2b centromeres notwithstanding, I have to stay with the Notch2NL genetic mutations found in Homo being the reason for Human brain size and cognitive functions. Rather than derail this thread I would refer you back to the Humans from Apes thread that you posted on a short time back. And since chromosome one is where the Notch2NL genes are located, the fusion of chromosome 2 wouldn't appear to be the culprit. There's more to this, of course but not for here would be better.

 

I agree with your analysis of a human evolved larger brain, but that is not necessarily what sets human apart from other apes. What sets human clearly apart from other apes is chromosome 2. Simply put, there are no other apes with 23 chromosomes.

Of interest may be that Early humans already had 23 chromosomes, and I doubt that their brains were much larger than other apes.

My main point was that if we want to know when hominid ancestor split off into humans, all we need to do is count the chromosomes. 24 = ape, 23 = human.

From wiki

 

Evolution

 

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Further information: Chimpanzee genome project

Humans have only twenty-three pairs of chromosomes, while all other extant members of Hominidae have twenty-four pairs.^[7] (It is believed that Neanderthals and Denisovans had twenty-three pairs.)^[7] Human chromosome 2 is a result of an end-to-end fusion of two ancestral chromosomes.^[8][9][10]

 

The evidence for this includes:

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• The correspondence of chromosome 2 to two ape chromosomes. The closest human relative, the chimpanzee, has nearly identical DNA sequences to human chromosome 2, but they are found in two separate chromosomes. The same is true of the more distant gorilla and orangutan.^[11][12]
• The presence of a vestigial centromere. Normally a chromosome has just one centromere, but in chromosome 2 there are remnants of a second centromere in the q21.3–q22.1 region.^[13]
• The presence of vestigial telomeres. These are normally found only at the ends of a chromosome, but in chromosome 2 there are additional telomere sequences in the q13 band, far from either end of the chromosome.^[14]
• We conclude that the locus cloned in cosmids c8.1 and c29B is the relic of an ancient telomere-telomere fusion and marks the point at which two ancestral ape chromosomes fused to give rise to human chromosome 2.

 

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We conclude that the locus cloned in cosmids c8.1 and c29B is the relic of an ancient telomere-telomere fusion and marks the point at which two ancestral ape chromosomes fused to give rise to human chromosome 2.

https://en.wikipedia.org/wiki/Chromosome_2#

 

[write4u]

On 2/15/2021 at 8:01 AM, Evolute said:

But what about the brain? How is it that Humans can build a Lexus and a Bonobo cannot?

But a Bonobo can learn to use a Lexus or a computer.  There are several apes who can express abstract ideas via sign language or computer imagery.

Koko the Gorilla was devastated when her manx kitten, which she had named "ALLBALL" (no tail), was run over by a car on the street. She sat for days in the window looking out, grieving and signing "allbball gone, no come back, Koko sad".

That clearly showed her understanding of the situation and her emotional status. 

[Evolute]

10 hours ago, write4u said:

That clearly showed her understanding of the situation and her emotional status.

 

Many animals do this. Elephants tenderly handle the bones of departed elephants. It's because intelligence isn't ours and ours alone. And yes, Primates can be taught to do all kinds of amazing things that they learn and that helps them communicate- but it's because they are taught. Give them a bicycle and they'll stare at it, throw it around and do whatever, but they will not know how to ride it. I saw a Chimp light a campfire with a match. But it was taught how to, not because it thought of it on their own. Brain-wise I see Great Apes as toddlers that can be taught things, because toddlers won't know of think of how to do most things by themselves either.

And certainly, count the chromosomes but there is no question that the Notch2NL copies in the Human development of the brain is the piece of he puzzle that separates us. We may have a different number of chromosomes but without the Notch2NL genetic variations we would just be apes with a different chromosome count. Biologically Humans have slower brain growth where stem cells create more progenitor cells than neuron cells. The greater amount of progenitors ultimately allow for more neurons to be created. Ape brains in the womb grow faster and so their stem cells do not create proportionally more progenitor cells but instead are bust creating neurons.

More neurons translate into a larger neocortex in Humans. Apes have the capacity to learn, Humans have a higher capacity to create. Apes can use a stick. Humans can shape and lash a piece of flint onto the end of one. It was Notch2NL A, B, and C genes paired with respective NBPF genes that set Humans apart from apes. There are many animals with different numbers of chromosome pairs. Humans happen to have fused chromosome 2 but that's not what gave us our brains. Our brains happened on chromosome 1 at the 1p12.1 locus which got copied to the 1q21.1 locus. If need be, I will cite papers supporting this. I also thank you for reengaging on the subject. Much appreciated.

Edited March 13, 2021 by Evolute

[write4u]

59 minutes ago, Evolute said:

Many animals do this. Elephants tenderly handle the bones of departed elephants. It's because intelligence isn't ours and ours alone. And yes, Primates can be taught to do all kinds of amazing things that they learn and that helps them communicate- but it's because they are taught. Give them a bicycle and they'll stare at it, throw it around and do whatever, but they will not know how to ride it. I saw a Chimp light a campfire with a match. But it was taught how to, not because it thought of it on their own. Brain-wise I see Great Apes as toddlers that can be taught things, because toddlers won't know of think of how to do most things by themselves either.

I believe there is one indisputable overriding factoid and that is "all skills are learned", from experience and observation. There is no such things as inherent knowledge.

The brain enters the world as a blank computer which is programmed by it's unique experiential environment.

There is no innate knowledge except some hardwired instinctual survival mechanisms such as the "fight or flight" mechanism, which already exhibits in single celled organisms. 

It takes human years to learn certain physical skills which are exceeded by much simpler animals. We may learn to ride a bicycle but so do apes or dogs. But a fawn may learn to walk in hours, which may take a human baby months to learn. "Necessity is the mother of invention"

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And certainly, count the chromosomes but there is no question that the Notch2NL copies in the Human development of the brain is the piece of he puzzle that separates us. We may have a different number of chromosomes but without the Notch2NL genetic variations we would just be apes with a different chromosome count. Biologically Humans have slower brain growth where stem cells create more progenitor cells than neuron cells. The greater amount of progenitors ultimately allow for more neurons to be created. Ape brains in the womb grow faster and so their stem cells do not create proportionally more progenitor cells but instead are bust creating neurons.

I agree, but all hominid apes have Notch2NL. It is just more evolved in humans. You cannot say that Notch2NL is what sets us apart.  We all share this genome to a greater or lesser extent. There are humans with extremely low IQ and there are apes with relative extremely high IQ, due to brain development and teaching.

OTOH, no apes, except humans, have 23 chromosomes and a human chromosome 2 which is twice as large and complex as the separate chromosomes 2p and 2 q in apes. It is clearly what completely separates humans (and Neaderthals) from all other apes.

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More neurons translate into a larger neocortex in Humans. Apes have the capacity to learn, Humans have a higher capacity to create. Apes can use a stick. Humans can shape and lash a piece of flint onto the end of one. It was Notch2NL A, B, and C genes paired with respective NBPF genes that set Humans apart from apes. There are many animals with different numbers of chromosome pairs. Humans happen to have fused chromosome 2 but that's not what gave us our brains. Our brains happened on chromosome 1 at the 1p12.1 locus which got copied to the 1q21.1 locus. If need be, I will cite papers supporting this. I also thank you for reengaging on the subject. Much appreciated.

I accept your greater knowledge.  My main point was, when examining hominid fossil remains, the easiest way to tell if it is human is by chromosome count. 

24 chromosomes = ancestral hominid , 23 chromosomes = human hominid. The number of chromosomes sets us "apart" from ancestral hominids.

p.s. the pleasure to learn new things is all mine.......☺️
 

Edited March 13, 2021 by write4u

[Evolute]

8 hours ago, write4u said:

p.s. the pleasure to learn new things is all mine.......☺️

As it is mine, write4u, I engage, not to debate, but for the sheer joy of learning and appreciate similar attitudes and goals. I also accept your chromosome pair statements because they are TRUE. My own goal here involves a hypothetical reason for why a Sasquatch- SHOULD IT EXIST- has no fire and no wheel even though it has been reported by many to have our more advanced primate body.

If the thing is real then somewhere along the way it didn't get the Human brain's capabilities. But a science Forum, I must respectfully say,  is probably no place for any Sasquatch kind of discussion. Nonetheless, this very recent discovery in the state of Kentucky in the US, by a primatologist, has me quite intrigued:

 

[write4u]

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Nonetheless, this very recent discovery in the state of Kentucky in the US, by a primatologist, has me quite intrigued:

I live in No. Idaho and have worked with the Kootenai Indian tribe. Several members of the tribe believe Sasquatch exists. While I am very skeptical, I respect the forest knowledge of local natives and am not in a hurry to dismiss the claim, unless it is shown that such a creature or tribe cannot exist.

[Evolute]

That speaks well of you. Like you, I am not 100% convinced WRT existence, and also keep the door somewhat open. And I do much prefer to see scientists wade in or investigate the subject, or any non-mainstream subject, for the same reason. Thank you for your input.

[write4u]

The beauty of the chromosomal fusion is that it sets humans clearly apart from other apes, but also confirms the original relationship of humans to a common ancestor. It is proof of a genetically beneficial mutation which took two separate parts and produced a single more complex organization.

IMO it is a persuasive argument against the concept of  "irreducible complexity".

Edited March 14, 2021 by write4u

[Evolute]

1 hour ago, write4u said:

The beauty of the chromosomal fusion is that it sets humans clearly apart from other apes, but also confirms the original relationship of humans to a common ancestor.

Agreed but the range in time of that fusion mutation is still a question. Yes Apes have chromosomes 2a and 2b which fused in Humans but there is no proof that it happened at the last KNOWN split between Chimps and Humans. There could still be another LCA after Pan troglodyte went one way and my hypothetical Last Common Ancestor went another. That hypothetical missing link may or may not have had a fused chromosome 2. So let's take it a step further.

IF the DNA found in Kentucky is really genus Pan, then it could very well still have the unfused chromosome 2. In which case, it could have evolved into a more contemporary primate body and THEN Human chromosome 2 fused in the Homo branch, leaving Sasquatches with Chromosome 2a and 2b, like the Great Apes. Otherwise, the only primate DNA that could ever be found in North America would only, and always, point to Human. And even in the case for Kentucky, what was collected was mitichondrial DNA which won't have chromosome 2, 2a, OR 2b. It would only have the base pairs found in mtDNA.

Human nuclear DNA has 3.2 billion base pairs with only two copies. Mitochondrial DNA has fewer that 16,700 base pairs but has hundreds if not thousands of copies. That's why it's so easy to get and test mtDNA. But depending on it's quality in the environment it may only show family. With better quality samples it can show genus. So metabarcoding targets mtDNA, which is why it can show a large diversity of organisms in one field sample, like from water, soil, ice, or snow. In either case, to find mtDNA of Chimps in the wilds of North America is pretty unusual if not impossible. But whatever the creature is that shed that DNA, it is showing enough Chimp DNA to say Pan. And the sample showed that as being a distinct genus, even though Humans themselves are said to be 98.9% Pan. Obviously more independent investigation and data is needed to corroborate anything.

Edited March 14, 2021 by Evolute

[write4u]

34 minutes ago, Evolute said:

IF the DNA found in Kentucky is really genus Pan, then it could very well still have the unfused chromosome 2. In which case, it could have evolved into a more contemporary primate body and THEN Human chromosome 2 fused in the Homo branch leaving Sasquatches with Chromosome 2a and 2b like the Great Apes. Otherwise, the only primate DNA that could ever be found in North America would only, and always, point to Human. And even in the case for Kentucky, what was collected was mitichondrial DNA which won't have chromosome 2, 2a, OR 2b. It would only have the base pairs found in mtDNA.

I see what you are saying, but that would assume a third completely different evolutionary path from our common ancestor. But there is no hard evidence for that, is there?

What we see today in other apes is the result of evolution without the chromosomal fusion. They had the same evolutionary time span as humans, but from the fossil records and current DNA count only humans (Neaderthal and Denison) have (had) the mutation. 

AFAIK there is not a single fossil that shows a non-human hominid with 23 chromosome pairs.  Even a single example would support your hypothesis, but there isn't any as yet!

That does not preclude the possibility of a separately evolved hominid, but if there is a Sasquatch, my guess would be a surviving evolved early Neaderthal or Denisovan or cross and would already have 23 chromosomes.

But then, nature has produced a host of some incredible creatures, which almost defy logic. Natural Selection has no preference except for survival long enough to procreate.

Edited March 14, 2021 by write4u

[Evolute]

Good post. But let's see if I can help clarify a bit. In my way of thinking, a Sasquatch wouldn't be Homo. It would be a similar to a Great Ape (hair, brain, etc.) but have a more evolved Human-like morphology to include bipedalism. In other words, instead of a Chimp/Homo split, it would be a Chimp/LCA-to-Humans-and-Sasquatch split. Not unlike the Gorrilla/LCA to Chimps-Homo split (as an analogy).

So a Sasquatch COULD still have chromosome 2a and 2b (24 pairs) but end up with a better, non-knuckle walking body because of a further evolved LCA after the Chimp split. That's the hypothetical Last Common Ancestor I'm talking about which would have gone on to split Sasquatches (apes) from Homo (Humans). It means there could have been one more primate evolutionary species AFTER Chimps that split into Sasquatch and Homo. Homo gets the fused chromosome 2 plus the better-brain Notch2NL Human variations. Sasquatch does not- it only gets an evolved, more robust, Human-like body.

And, of course, this is all hypothetical. But if genus Chimp-type DNA was truly found in the wilds of NA then maybe not? That bit of news came after first I entered this thread which is why I've shifted a bit from where I began.

Edited March 14, 2021 by Evolute

[write4u]

An interesting projection. Time may tell......😄

[write4u]

Discovered another piece of the puzzle.

Evolution

 

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The genus Homo evolved and diverged from other hominins in Africa several million years ago, after the human clade split from the chimpanzee lineage of the hominids (great apes) branch of the primates.^[26] Modern humans, specifically the subspecies Homo sapiens sapiens, proceeded to colonize all the continents and larger islands, arriving in Eurasia 125,000–60,000 years ago,^[27][28] Australia around 65,000 years ago,^[29] the Americas around 15,000 years ago, and remote islands such as Hawaii, Easter Island, Madagascar, and New Zealand between the years 300 and 1280.^[30][31]

Family tree showing the extant hominoids: humans (genus Homo), chimpanzees and bonobos (genus Pan), gorillas (genus Gorilla), orangutans (genus Pongo), and gibbons (four genera of the family Hylobatidae: Hylobates, Hoolock, Nomascus, and Symphalangus). All except gibbons are hominids.

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The closest living relatives of humans are chimpanzees and bonobos (genus Pan),^[32][33] as well as gorillas (genus Gorilla).^[34] The gibbons (family Hylobatidae) and orangutans (genus Pongo) were the first groups to split from the lineage leading to humans, then gorillas, and finally, chimpanzees. The splitting date between human and chimpanzee lineages is placed 4–8 million years ago, during the late Miocene epoch.^[35][36] During this split, chromosome 2 was formed from the joining of two other chromosomes, leaving humans with only 23 pairs of chromosomes, compared to 24 for the other apes.^[37]

 

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The earliest fossils that have been proposed as members of the hominin lineage are Sahelanthropus tchadensis, dating from 7 million years ago; Orrorin tugenensis, dating from 5.7 million years ago; and Ardipithecus kadabba, dating to 5.6 million years ago. From these early species, the australopithecines arose around 4 million years ago, diverging into robust (Paranthropus) and gracile (Australopithecus) branches,^[38] possibly one of which—such as A. garhi, dating to 2.5 million years ago—is a direct ancestor of the genus Homo.^[39]

^{https://en.wikipedia.org/wiki/Human}

 

 

[write4u]

On 7/27/2020 at 12:40 PM, gravitymall said:

I think social cooperation is key. High intelligence seems like a sure fire thing for evolution to select for, yet we're the only ones. Our babies are some of the most fragile when they're born, yet they're able to develop because of humans socially cooperating on a larger scale than any other animal.

That seems not quite accurate. Bonobos are extremely social and probably the most peaceful of the great apes. This probably stems from the fact that Bonobos have a matriarchal society. The females are the dominant gender. Visiting Bonobo travelers are welcomed in the tribe and food and females shared for bonding .

One of the scientists studying the Bonobos remarked that in a Bonobo camp you can go to sleep and be assured you will never be attacked by a member of the tribe during the night.

An excellent example of freely sharing  food is found in this little clip. The ape with the food actually unlocking the door to share the food with the hungry visitor.

Bonobo cooperation is remarkable. In a test of solving problems which required cooperation between several members, the Bonobos immediately set to try and solve the problems where the Common Chimps quibbled for dominance and possession.

They are eager to learn and can adapt to symbolic language if taught early enough.

 

Edited March 14, 2021 by write4u

[Evolute]

Yep, and graphed out it looks like this. See that line with the question mark coming down from Sahelanthropus tchadensis, Ardipithicus  to a three way split that includes Orrorin? That's the line I put Sasquatches on. But some say it should be a line that parallels Paranthropus because of bipedalism. But I disagree with that thinking because of what I think Sasquatch really is: A bipedal ape with an ap brain, and yes, maybe even the unfused chromosome 2 of the Great Apes. So everything after Panini leads to Humans but I propose a dedicated Sasquatch line right after Panini. If Sahelanthropus or Ardipithucus is out Last Common Ancestor (unlikely) then it could be the LCA of both the Human  and the Sasquatch (Another Great Ape) lines.

[Evolute]

I would like to add that after 7 million years Chimps are still Chimps and Sasquatches, SHOULD THEY EVEN EXIST AT ALL, are still Sasquatches. However the Homo line, in spite of it sometimes concurrent population branches, advanced to us. It just makes me wonder if the Chimp DNA that primatologist found in Kentucky was Chimp DNA because Sasquatches have more of it than we do. Talk about a science mystery!

BUT! Here's the kicker: If these things are real then there's just no way someone hasn't known about it all this time- especially in this modern surveillance age. It's worrisome to think what that might mean.

Edited March 15, 2021 by Evolute

[write4u]

Seems that Sasquatch was a hominid but not human. The timeline shows that Sasquatch appeared several million years before the fusion of chromosome 2 which split Homo Sapiens and Neaderthals from all other hominids and is peculiar only to humans.

Origin of human chromosome 2: An ancestral telomere-telomere fusion

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Similarities in chromosome banding patterns and hybridization homologies between ape and human chromosomes suggest that human chromosome 2 arose out of the fusion of two ancestral ape chromosomes (1-3). Molecular data show evidence that this event must have occurred only a few million years ago

https://www.pnas.org/content/pnas/88/20/9051.full.pdf