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Chronologic4
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No it’s not.
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o_mlly
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I assume when you write “people” you mean homo sapiens. If so, how do we know that other homo sapiens were simultaneously living or ancestral to M-Eve and Y-Adam?
Do we know that these individuals lacked the necessary chromosomes to be homo sapiens?
If all homo sapiens inherited their Y-chromosome form Y-Adam and absent that Y-chromosome a being is not homo sapiens then how is it possible that Y-Adam had ancestors that were homo sapiens?
The bottleneck argument, I think, simply begs the question – one cannot have a bottleneck event for a population that doesn’t exist. The question being: Does the specie homo sapiens have a singular ancestor?
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o_mlly
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I quoted the geneticist’s conclusion; no more, no less.
Are you trying to say that M-Eve is not the one maternal source for all humans?
And to claim that Eve was never one woman goes beyond the data and violates the logical law of the excluded middle.
What about Y-Adam?
And to write that “she [homo sapiens – female] has always been many” would deny the fundamental claim of evolution: all species evolved. Science has not proven that she was not one.
Scientists generally agree that mutation and micro evolution are valid claims. However, they still dispute the claim that macro evolution is valid as an explanation for different species. So do I.
- Homo Sapiens did not always exist.
- Homo Sapiens exist as a result of multiple micro evolution events.
- But Homo Sapiens could not exist in the absence of a singular kind of micro evolution event.
The uniqueness of that micro evolution event that caused the first homo sapiens individual begs us to ask: What was so different? Did the gene pool change? How? What induced this new possibility in these particular non-human parents to produce a new specie?
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SeraficLeo
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Okay I’m laughing at this point.
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Bradskii
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OK, Eve was never just one woman. Look at it this way. Your grandkids oldest living ancestor is never just the one person. It changes as people die off. When great grandma Mary shuffles off this mortal coil, then their OLA becomes someone else. The MRCA is a woman who was the most recent common ancestor at any one time. When one contemporary branch line dies out, the MRCA becomes another woman.Bradskii:
I quoted the geneticist’s conclusion; no more, no less.
Are you trying to say that M-Eve is not the one maternal source for all humans?
And to claim that Eve was never one woman goes beyond the data and violates the logical law of the excluded middle.
What about Y-Adam?
And to write that “she [homo sapiens – female] has always been many” would deny the fundamental claim of evolution: all species evolved. Science has not proven that she was not one.
Scientists generally agree that mutation and micro evolution are valid claims. However, they still dispute the claim that macro evolution is valid as an explanation for different species. So do I.
3 does not deny that this singular kind of micro evolution event had multiple occurrences. That may or may not be true and is not proven either way by science. But there must be at least one.
- Homo Sapiens did not always exist.
- Homo Sapiens exist as a result of multiple micro evolution events.
- But Homo Sapiens could not exist in the absence of a singular kind of micro evolution event.
The uniqueness of that micro evolution event that caused the first homo sapiens individual begs us to ask: What was so different? Did the gene pool change? How? What induced this new possibility in these particular non-human parents to produce a new specie?
I’ll grant you one thing…this subject needs a fair amount of investigation to get one’s head around it.
And there never was a single event that turned what wasn’t a human into what was. I think that was what you were referring to. There are no dividing lines. There is even no real agreement at what point Homo splits from what came before it.
It certainly wasn’t the case that an Australopithicus afarensis got zapped by some cosmic ray, had some genes bent and twisted and then gave birth to a Homo habilis.
It’s like a mile long pole which is red at one end and blue the other. It’s definitely red over there (Austolapithicus afarensis) and definitely blue waaay over there (Homo habilis) but can you tell at which exact point it changed from one to the other?
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Bradskii
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And to confirm…yes. She is not the one maternal source. When one MRCA’s line to the here and now dies out then the most recent maternal source is another woman. So if you could go back in time you could point to one woman on the Monday and say ‘That is M-Eve’ and on Tuesday it would be someone else.
And it should be obvious that M-Eve had a mother in any case.
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rossum
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Homo sapiens appeared between 250,000 years ago and 200,000 years ago. M-Eve and Y-Adam are between 200,000 and 150,000 years ago. They are not the first humans, they lived among a surrounding population of other humans.
They did not lack any chromosomes, most of them had different versions of mitochondrial DNA and Y-chromosomes. Those other versions have since died out. Some of the female direct ancestors of M-Eve will have carried her variant of mitochondrial DNA. Similarly some of Y-Adam’s direct male ancestors will have carried his variant of the Y-chromosome.
All living male H. sapiens have inherited from Y-Adam. His contemporaries did not, but they are not alive today. Y-Adam inherited his Y-chromosome from his human father, just as M-Eve inherited her mitochondrial DNA from her human mother.
The bottleneck applies to a lot more of our DNA than just one chromosome and the extra-nuclear DNA. Our other chromosomes show that we have a lot more than two ancestors. You might want to read up on the concept of the MRCA: most recent common ancestor.
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rossum
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Evolution is not intelligent; it design by a process of massively parallel trial and error.
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o_mlly
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My oldest ancestor is, of course, not my oldest living ancestor. It is the former that we are discussing.
There is no evidence to write that Eve, the first female homo sapiens, was “never just one woman”.
Scientists have determined that an MRCA exists meaning they have evidence of the most recent known MRCA but have no evidence yet that a prior MRCA existed. In the absence of evidence to the contrary, that MRCA may also be the first Eve or the OKCA (oldest known common ancestor).
I have difficulty with the apparent inconsistency in the above. First, to claim (again) that a thing “never” happened in a historiographical science like evolution where the next rock turned over may also turn over long held beliefs on their head is unfounded. Second, to write that there is no real agreement “at what point Homo splits” implies that the point exists; we just don’t know when that point occurred.
As I’m sure you know the above is an argument from ignorance fallacy. Because we don’t know the “exact point” does not mean that point does not exist. Keep looking!
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o_mlly
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I rather think that if M-Eve had a mother then M-Eve is not M-Eve but her mother is.
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o_mlly
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The dating ranges overlap. Please cite the argument or evidence that M-Eve and Y-Adam lived among a population of ancestral human beings.
If Y-Adam inherited his Y-chromosome from his human father then isn’t Y-Adam really that human father? Ditto Eve-M.
Thank you for the link. I’ll try to read later today or tomorrow.
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edwest211
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The Bible tells us Eve was formed from Adam’s side by God.
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rossum
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We are indeed all descended from M-Eve’s mother, grandmother, great-grandmother etc. but M-Eve is more recent than her ancestors (obviously). M-Eve is an MRCA, where MR stands for “Most Recent”. That means that M-Eve had at least two daughters and at least two of those daughters have descendants living today. Those daughters only gave rise to part of the current population; M-Eve gave rise to all of the current population.
Those ancestors: mother, grandmother etc. might possibly be the Genesis Eve, since they are ancestors of all living humans. There is no requirement for the Genesis Eve to be “most recent”.
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rossum
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Y-Adam is derived from the transmission of the Y-chromosome from father to son. Mothers are not involved, since they have XX instead of XY. That makes the line of transmission very easy to work out; we only have to deal with one parent at each generation, so the line does not branch when we work backwards. Similarly for the maternal transmission of mitochondrial DNA, only one parent, the mother, needs to be considered.
Other chromosomes are much more difficult to calculate. We have 23 pairs, giving 46 chromosomes, half from each parent. The Y chromosome, if present, must have come from the father. The other 45, or 46 in females, came from both parents. That means that as we go back over the generations there are 2 parents, 4 grandparents, 8 great-grandparents, 16, 32, 64, 128 etc. to consider. In a remarkably short time you have more ‘ancestors’ than the population of the earth back then. Hence we have to resort to a statistical survey of modern genes over the whole population and extrapolate that back through time. We know mutation rates and we know how genes spread through a population, so we can calculate back to see what the overall genetics of the population back at a given time was like.
One person can have two variants of a gene, called alleles. For example, there is an allele for blue eyes and an allele for brown eyes. Some parts of our genome, particularly the immune system, have thousands of alleles for a single gene in the general population. Those alleles go back a very long way, we share hundreds of them with chimpanzees. That makes sense since we can both be exposed to the same or similar diseases.
An individual can carry two alleles maximum. Once we know the number of alleles we can estimate a minimum population size for that time. The actual population will be larger, since alleles may be shared between more than one person – brown eyes for example. The minimum estimate for the human population is 10,000 breeding pairs about 70,000 years ago. It may have been smaller much earlier, but that would have been over 500,000 years ago, well before Homo sapiens evolved.
This is the same as above for M-Eve. Both Y-Adam and M-Eve are MRCAs, where MR is “most recent”. Their ancestors are not “most recent”.
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Bradskii
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No…I used that as an example. We are NOT discussing YOUR oldest ancestor but the most recent COMMON ancestor of all people who are alive today. YOUR oldest ancestor goes back billions of years.
This is a difficult enough subject to grasp as it is. I am not in a position to be able to correct any misunderstandings that you might have, although I know enough about it that I can point them out. Please do not use any of my posts as a basis for your arguments. I strongly recommend that you read more about it.
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o_mlly
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It’s not that difficult to grasp. The link @rossum provided gives us the methodology.
MRCA is an inference gained not by observation but through computer simulations with assumptions on probability distributions, informed guesses on genetic variables and a reliable random number generator (if there truly is such a thing).
OK so far. Now, the introduction of M-Eve and Y-Adam regrettably were assigned to the simulation output not by the scientists but by a science fiction writer. And, he obviously did not know what outputs the study produced which have nothing to do with the biblical pair known as the first human beings.
Subsequently, the study’s conclusions as usual have been criticized by peers. The important point is that the MRCA has nothing to do with Adam and Eve. I regret posting that pseudo MIT misnomer.
So I’m hard pressed to understand how those who claimed to understand the MRCA use that study as evidence that there is no Eve. Why did they continue to reference M-Eve and Y-Adam in subsequent posts, perpetuating the misnomers rather than correcting them?
So the question remains unanswered: Is homo sapiens the result of a singularity, a one time only macro evolution event? Christian and Jewish theology, “Yes”. Science, “We don’t know but we’ll keep on looking.”
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Bradskii
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M-Eve is the name that was given by Rebecca Cann. One of those who did the original study. https://science.howstuffworks.com/life/evolution/female-ancestor.htm
“The study’s lead author, Rebecca Cann, called her colleagues’ and her choice to use Eve as the name “a playful misnomer,” and pointed out that the study wasn’t implying that the Mitochondrial Eve wasn’t the first – or only – woman on Earth during the time she lived [source: Cann]. Instead, this woman is simply the most recent person to whom all people can trace their genealogy. In other words, there were many women who came before her and many women who came after, but her life is the point from which all modern branches on humanity’s family tree grew.”
The name isn’t ‘wrong’. It’s a misnomer in that it doesn’t specifically refer to the biblical Eve. Which didn’t (and doesn’t) stop people from inferring that it does.
Those who understand the subject well enough aren’t saying Eve didn’t exist. They are saying that M-Eve is NOT the woman referred to in the bible.
And I don’t know what you mean by ‘a one time macro event’. Speciation isn’t an event. It’s many minor changes that end up in one species splitting from another. Saying it’s ‘an event’ is like saying that developing from a child into an adult is a one time event.
If you accept that but are asking if it’s a one time occurence, then the answer is a most definite yes. There is zero evidence that Homo sapien evolved more than the one time. To that extent, it was a one off.
But you can’t hold that fact up to show we are special in some way, because every species that ever existed was a one off.
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o_mlly
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Using the Wikipedia link provided by @rossum, I found quite a different story on the misnomer:
Pleeeeease stop the spinning.
We could have used that post 20 or so posts ago. But, better late than never. Do you therefore revise your previous 2 post from “Eve” to “M-Eve” (as meaningless as the term is). Why is it important? Because there is no dispute between Catholicism and evolution if you revise but without it faith and science are in conflict.
We can now leave M-Eve and Y-Adam.
The logic is at worst circular and at best abductive – science’s self granted license to be creationists (pun intended). Scientists observe different kinds of animals but they have never observed any one kind come into being. Scientists observe in particular kinds of animals variations in the population. Some variations are better to suited to survive than others.
Now comes the creative part. Scientists rightly limit themselves to identifying natural processes to explain observed phenomena. How can they explain different kinds of animals? Answer, create a hypothesis using observed natural processes to explain unobserved processes. In a word, speciation. “Kinds” become “species” and “macro evolution” becomes the un-observable process explaining their origins.
And all of this is OK until one elevates that abductive hypothesis (best guess) to be science fact. Please stop doing that.
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edwest211
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The last sentence is a good summary of what’s going on here. A secular ‘reality’ is being promoted that says humans are not exceptional or special. The Church tells us otherwise.
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Bradskii
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The term isn’t wrong. It’s inaccurate (a misnomer) as far as some Christians understand the term. They understand the term to refer to the biblical Eve. It doesn’t. If it referred to a single woman from whom all people have descended then there would be no conflict with some Christians and evolution. But it doesn’t, so there is.Bradskii:
Using the Wikipedia link provided by @rossum, I found quite a different story on the misnomer:
Pleeeeease stop the spinning.
We could have used that post 20 or so posts ago. But, better late than never. Do you therefore revise your previous 2 post from “Eve” to “M-Eve” (as meaningless as the term is). Why is it important? Because there is no dispute between Catholicism and evolution if you revise but without it faith and science are in conflict.
Either those Christians can continue to exhibit their scientific ignorance about the matter or they can learn enough about the subject to realise that the MRCA (aka M-Eve) is not Adam’s wife and find something else to complain about.
Presumably that evolution denies God or that we have the age of the planet wrong. Oh, hi Ed. Didn’t see you come in. Any answers on the age question?
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