Adam

[bibleblevr]

Was Adam one man? A chosen group of people? Or all of humanity.

When Man evolved from lower beings, He eventually was given a spirit by God, this new creation was Adam, the Bible declares that although he was first formed out of dust, God breathed into his nostrils the breath of life and he became a living soul capable of communion with God. So who was this Adam?

 

[Steve Petersen]

Possibly he was the oldest ancestor to whom the patriarchs could trace their ancestry, though not really the first human.

 

[gluadys]

Although I don't like the sarcastic way it is phrased I chose "None". The other alternative is "All of the human race at the time." I don't think this is what Adam in Genesis is. I think Adam is a literary character who represents all of the human race all of the time--present and future as well as the past.

 

[mark kennedy]

Take a look at Luke's genealogy or Paul's discussion of Adam in Romans 5. I won't vote in the poll but he was 'one man', Paul, Luke and Moses are clear enough on that point.

Grace and peace,
Mark

 

[solarwave]

I voted for "All of the human race at the time" even though this isn't what I think, it is just closers to what I think than the 4th option which made is sound as if Adam being non-historical is a bad thing.

My opinion is that Adam represents all humans who ever existed since what happened to Adam can be translated into the life of every human was has lived, fallen from grace, and some who are raised up again.

 

[elopez]

Was Adam one man? A chosen group of people? Or all of humanity.

When Man evolved from lower beings, He eventually was given a spirit by God, this new creation was Adam, the Bible declares that although he was first formed out of dust, God breathed into his nostrils the breath of life and he became a living soul capable of communion with God. So who was this Adam?

Adam was the first man endowed with a soul that was capable of directly communicating with God. Adam was created in an original state of holiness, that is, in a state of sinlessness. Therefore Adam cannot actually be humanity, since every subsequent individual would differentiate from Adam in that respect now that all are born in a state of sin as a result of Adam's sin.

So I say Adam is one man, since the first personal sin can be traced back to him.

 

[Papias]

It's important to remember that one common TE position (and the one I hold, along with literally millions of others, including whole churches) is that there WAS a literal, first person, Adam. He was a member of a community, and was the first person in the ape to human gradual change.


Remember that there is variation, and that mutations are in individuals before they spread to the rest of the tribe. So as the whole community gradually evolves from ape to human, whatever arbitrary characteristic is used to define "being human", one individual will be the first to cross that line. Of course, all humans will be descended from him, just as they are all descended from others as well. Think of that mayflower club, which only allows members who are descended from the few people who came over from Europe on the mayflower. That club today has thousands of members, and in a few thousand years or so, literally everyone on earth will be descended from those on the mayflower. The same holds true for an individual, so long as they have a few kids. Thus, if you have a few kids, it is very likely that in a few thousand years, literally everyone on earth will be descended from you as well. It's all a mix.

So, coupling that with the thing above about the literal Adam, it all works well.

Papias

P. S. Mark wrote:

Take a look at Luke's genealogy

I hope Mark realizes that the geneologies are figurative. They can't be literal because if taken literally, Lk contradicts Mt, who contradicts 1 Cr.

 

[bdfoster]

Of course, all humans will be descended from him, just as they are all descended from others as well. Think of that mayflower club, which only allows members who are descended from the few people who came over from Europe on the mayflower. That club today has thousands of members, and in a few thousand years or so, literally everyone on earth will be descended from those on the mayflower.

I don't think this is necessarily true. The fact that we have races indicates that isolation of populations does occur. DNA studies have shown that a remarkable number of people are descended from Genghis Khan. But those people are in Asia and there are lines of people that may never have the opportunity to breed with Khanites. DNA studies have identified markers within many races, but these markers my never be homogenized throughout humanity. In a few thousand years Mayflower DNA may be found in everyone in North America but what about Africa? Or what about isolated aboriginal tribes in the Philippines?

The same holds true for an individual, so long as they have a few kids. Thus, if you have a few kids, it is very likely that in a few thousand years, literally everyone on earth will be descended from you as well. It's all a mix.

But if humanness, or the Image of God, is due to piece of DNA that has to be homogenized throughout humanity, then what about those humans that were biologically isolated from Adam for thousands of years? If Adam was Semitic what about the "humanness" of Polynesians. Or going back further if Adam was a Homo Erectus in Africa, what about Homo Erectus in Asia?

 

[Papias]

Brent wrote:

Papias wrote:
and in a few thousand years or so, literally everyone on earth will be descended from those on the mayflower.

I don't think this is necessarily true. The fact that we have races indicates that isolation of populations does occur. DNA studies have shown that a remarkable number of people are descended from Genghis Khan. But those people are in Asia and there are lines of people that may never have the opportunity to breed with Khanites. DNA studies have identified markers within many races, but these markers my never be homogenized throughout humanity. In a few thousand years Mayflower DNA may be found in everyone in North America but what about Africa? Or what about isolated aboriginal tribes in the Philippines?

Hi Brent, it's nice to meet you.

First, because we each only get one allele from each parent (the mixing hypothesis is false - let me know if you don't know what I'm talking about), the fact that we are descended from nearly everyone alive a few thousand years ago doesn't mean that races won't exist. Many people in a thousand years will be descended from people on the mayflower, and will not have DNA from mayflower people, because those alleles didn't happen to end up in the gametes. The DNA will never be homogenized, and that's not what I'm arguing.

Races will still exist just fine because of percentage. For instance, if I'm 99.99999% european ancestry, with 0.00001% Ghengis Khan, I'm a caucasian, but I do still have GK ancestry. I look very different from someone with 99.9999% Asian ancestry, and 0.0001% Charlemange ancestry.

Those weren't exaggerated percentages, they were quite possible. Do the math. You have 2 parents, 4 grandparents, 8, 16, 32, 64, 128, 256, ~500, ~1000, etc. - that's only about 500 years. Going back just 1,000 years gives a million people. The same goes for descendants, going forward.

So try this little thought experiment. Pharaoh Khafra, in 2540 BC, has several kids, as rich rulers tend to do. Several of them are not in line for royal succession, and as such are simply in the population. Going by average 2 kid survival (out of perhaps 10 babies born) and assuming no population growth (which only makes my case stronger), that would be 2, 4, 8, 16, 32, 64, 128..... 1,000 descendants by 2000 BC, a million by 1500 BC, and so on. Out of these millions in 1400 BC, it's inevitable that some will be merchants or will travel to Greece, italy, or so on. By 500 BC that's a thousand descendants in Italy (growing from 1 or so in 1400 BC), by the time of Jesus that's millions in Italy, and of course some of those have traveled to neighboring Germany, France or farther like ireland. By the 1200's that's dozens of millions in those areas too.

Since you have thousands of European ancestors from that time and place, it's extremely likely that at least one of those millions is one of your thousands of ancestors in that time and place. So, you, Brent, are almost certainly a direct descendant of Khafra, who lied for thousands of years in the second pyramid at Giza. It's amazing, but you can do the math yourself. The same holds true for Yan Di, emperor of china in 2700BC, or for those who built the Goseck circle around 4,900 BC, or Otzi the iceman, or the murderer who shot and killed Otzi, and so on. We are all direct descendants of them all.

In all these cases, the descendants quickly become everyone in the population. Getting your descendants into Africa in a few thousand years is trivially easy, as is every major continent, especially with air travel. Some pacific islands will take a few more centuries, of course, but for each one, remember that soon nearly all of the earth will be your descendants, so practically any immigrant will bring in your line, and then, within a few short centuries, everyone on the island is your descendant.

But if humanness, or the Image of God, is due to piece of DNA that has to be homogenized throughout humanity,

Selection will make beneficial traits become present in everyone, because if anyone doesn't have it, they don't reproduce. Thus the DNA for big, logical brains is indeed in every human (except recent losses like birth defects). It's in everyone because they inherited it - and it predates most of what we think of as races (like white skin) anyway.

then what about those humans that were biologically isolated from Adam for thousands of years?

There are none. The transition to rational thought had to be at least 80,000 or more years ago (see the skulls here: 29+ Evidences for Macroevolution: Part 1 ). based on how advanced the skulls of say, skull "I" are. All humans are direct descendants of Adam. Skull "I" is at over 100,000 years. Try the math at the start of this post with a year of 100,000 BC, and you'll see how easy all of this is.

If Adam was Semitic what about the "humanness" of Polynesians. Or going back further if Adam was a Homo Erectus in Africa, what about Homo Erectus in Asia?

Homo Erectus in Africa and Asia had hundreds of thousands of years of time for a member here and there to emigrate. They thus are not speciated, and form one breeding population. You saw above how just a few thousand years takes care of this, and with homo erectus we have hundreds of thousands of years. Since all humans have inherited the DNA for rational thought, in all races, it's clear that all humans are direct descendants of proto-humans with rational thought. That would be Adam. See my previous comment.

Does that make sense? Is there a problem with any of the math? It works even better when one realizes that the population of humans has been increasing over that time, and so many of these humans had more than 2 kids that survived to reproduce.

Papias

 

[1whirlwind]

Adam was one man, not the first man on earth but the first man in the line to Christ. The others, all races, were created on the sixth day but Adam was formed after God's day of rest. The "days" being God's days of a thousand years.


.

 

[bdfoster]

Hi Brent, it's nice to meet you.

Hi Papias
Thanks for the thorough post. It is well thought out and has a lot of information. I will try to do it justice in response. I think our main difference is not over math (thank God, I'm retired; I try to do as little math as possible!) but over the details of how lineages propagate.

The lineage of sexually reproducing organisms can be represented by a family tree. The "tree of life" showing the relationship of all life, is a massive family tree. After a lineage has split, no organism can go back and be ancestral to a branch that it doesn't occupy. Humans and chimps may have a common ancestor but neither is ancestral to the other. All human races can interbreed. The existence of races indicates that there has been branching within the human lineage. But the isolation has not been long enough for speciation to occur and because of this, the branching is not as exclusive as it is further down on the tree of life. A human can go back and be an "ancestor" to members of another branch, but only if the isolation is removed.

First, because we each only get one allele from each parent (the mixing hypothesis is false - let me know if you don't know what I'm talking about), the fact that we are descended from nearly everyone alive a few thousand years ago doesn't mean that races won't exist.

Actually we get about 2.9 billion alleles from each parent (one for each base pair).

Many people in a thousand years will be descended from people on the mayflower, and will not have DNA from mayflower people, because those alleles didn't happen to end up in the gametes.

No, this is not true. Each parent gives 2.9 billion alleles to it's offspring. With each generation the genetic contribution of the previous generation is halved. The genetic contribution of that original parent is reduced the factor, 1/2^n where n is the number of generations. After 1 generation it's 1/2, after 2 it's 1/4, 3 is 1/8, 4 is 1/16 etc. The denominator doubles after each generation. After dozens of generations the allelic contribution of the original parent would indeed be negligible by this reasoning. But as you pointed out, inheritance is not by mixing. Whole genes are transferred, and if a gene codes for a useful trait it will be preferentially retained. The 23,000 or so genes that make up the human genome are the genetic remnants of ancestors that lived billions of years ago. Anyone in a thousand years who claims to be a mayflower descendant better have the DNA to show it, because genetic markers indicating ancestry do persist.

Races will still exist just fine because of percentage. For instance, if I'm 99.99999% european ancestry, with 0.00001% Ghengis Khan, I'm a caucasian, but I do still have GK ancestry. I look very different from someone with 99.9999% Asian ancestry, and 0.0001% Charlemange ancestry.

The study I mentioned about Genghis Khan descendants looked at a specific genetic marker that shows up in Khan descendants. The findings of the study (which I am not prepared to dispute) indicate that about 0.5% of the world's male population, or roughly 16 million individuals, are descended from Khan. It was a Y-chromosomal study so the figures can probably doubled to include females. That isn't even all of Asia much less all the world. Ancestry from an individual is not by percent. Either you are in a lineage or you are not. According to this study you are probably not in Khan's line, and you probably do not have 0.00001% Genghis Khan ancestry.

Those weren't exaggerated percentages, they were quite possible. Do the math. You have 2 parents, 4 grandparents, 8, 16, 32, 64, 128, 256, ~500, ~1000, etc. - that's only about 500 years. Going back just 1,000 years gives a million people. The same goes for descendants, going forward.

Yes you are definitely right about that. And assuming a nice well-behaved population with nothing to do but procreate, your math is inescapable. Of course to get years you have to assume a number of years per generation. But that's perfectly reasonable.

So try this little thought experiment. Pharaoh Khafra, in 2540 BC, has several kids, as rich rulers tend to do. Several of them are not in line for royal succession, and as such are simply in the population. Going by average 2 kid survival (out of perhaps 10 babies born) and assuming no population growth (which only makes my case stronger), that would be 2, 4, 8, 16, 32, 64, 128..... 1,000 descendants by 2000 BC, a million by 1500 BC, and so on. Out of these millions in 1400 BC, it's inevitable that some will be merchants or will travel to Greece, italy, or so on. By 500 BC that's a thousand descendants in Italy (growing from 1 or so in 1400 BC), by the time of Jesus that's millions in Italy, and of course some of those have traveled to neighboring Germany, France or farther like ireland. By the 1200's that's dozens of millions in those areas too.

Since you have thousands of European ancestors from that time and place, it's extremely likely that at least one of those millions is one of your thousands of ancestors in that time and place. So, you, Brent, are almost certainly a direct descendant of Khafra, who lied for thousands of years in the second pyramid at Giza. It's amazing, but you can do the math yourself. The same holds true for Yan Di, emperor of china in 2700BC, or for those who built the Goseck circle around 4,900 BC, or Otzi the iceman, or the murderer who shot and killed Otzi, and so on. We are all direct descendants of them all.

In all these cases, the descendants quickly become everyone in the population. Getting your descendants into Africa in a few thousand years is trivially easy, as is every major continent, especially with air travel. Some pacific islands will take a few more centuries, of course, but for each one, remember that soon nearly all of the earth will be your descendants, so practically any immigrant will bring in your line, and then, within a few short centuries, everyone on the island is your descendant.

There are a number of problems with this. First you seem to be equating number of descendants with an assurance that those descendants will penetrate every human lineage. This has not happened in the past for a number of reasons. Of course it may in the future because all humans can interbreed and air travel is removing geographic barriers that once caused genetic isolation. Yes Khafra probably had a few kids. And maybe one of them sailed to South America on a raft. But more likely the people the Spaniards found there (who probably were descendents of Khfra!) got there by another route. A route that involved migrations through Asia and probably north America. Migrations like that, and the genetic legacy they leave behind are increasingly the subject of DNA studies. Khafra probably was not ancestral to the aboriginal people of North and South America at the time of their first contact with Europeans.

Repeated DNA studies have shown that dogs are NOT descended from coyotes. The latest studies suggest that domestic dogs are descended from a single group of wolves in Asia about 16,000 years ago. But dogs, wolves, and coyotes can all interbreed. In fact a neighbor of mine has 50 - 75 feral dogs. There are no wild coyotes around here. They have all interbred with her pack. Many of her dogs are most definitely descended from coyotes! Dogs, coyotes, and wolves, just like the different races of humans can interbreed (ok not all together, that would be sick!). So the branches they occupy on the tree of life intertwine. This outer canopy on the tree of life has trillions of branches, for each new branch in every family tree. But these coyotes can only be ancestral to the branches they are able to touch. They can't go back and be ancestral to a lineage that branched on another continent 5 million years ago. In spite of this local hybridization, which certainly occurs any time dogs, coyotes, and wolves come into contact, does not change the fact that dogs are NOT descended from coyotes. No matter how hard they tried and are still trying, coyotes have failed to leave their DNA in the dog genome.

I don't share your opinion that it is trivially easy for a persons descendents to populate other continents and islands. Of course it is now with air travel and modern shipping. But before the age of exploration, ocean travel was a major barrier to human migration. The indigenous human populations of the New World, Australia, and Pacific Islands were isolated for significant periods, prior to their first European contact.

But if humanness, or the Image of God, is due to piece of DNA that has to be homogenized throughout humanity,

Selection will make beneficial traits become present in everyone, because if anyone doesn't have it, they don't reproduce. Thus the DNA for big, logical brains is indeed in every human (except recent losses like birth defects). It's in everyone because they inherited it - and it predates most of what we think of as races (like white skin) anyway.

then what about those humans that were biologically isolated from Adam for thousands of years?

There are none. The transition to rational thought had to be at least 80,000 or more years ago (see the skulls here: 29+ Evidences for Macroevolution: Part 1 ). based on how advanced the skulls of say, skull "I" are. All humans are direct descendants of Adam. Skull "I" is at over 100,000 years. Try the math at the start of this post with a year of 100,000 BC, and you'll see how easy all of this is.

If Adam was Semitic what about the "humanness" of Polynesians. Or going back further if Adam was a Homo Erectus in Africa, what about Homo Erectus in Asia?

Homo Erectus in Africa and Asia had hundreds of thousands of years of time for a member here and there to emigrate. They thus are not speciated, and form one breeding population. You saw above how just a few thousand years takes care of this, and with homo erectus we have hundreds of thousands of years. Since all humans have inherited the DNA for rational thought, in all races, it's clear that all humans are direct descendants of proto-humans with rational thought. That would be Adam. See my previous comment.

Does that make sense? Is there a problem with any of the math? It works even better when one realizes that the population of humans has been increasing over that time, and so many of these humans had more than 2 kids that survived to reproduce.

Papias

OK, it seems to me the bottom line is, if Adam was born 80-100,000 years ago in Africa, then yes all humans are probably biologically descended from him. If Adam was a Neolithic farmer in Mesopotamia, the indigenous populations of the New World were NOT his descendants at the time of first European contact.

You seem to equate humanness (image of God?) with the onset of rational thought, or some characteristic of humans that is genetically inheritable. What if dolphins evolved rational thought? OK you could always think of some other criteria for humanity that dolphins don't have. Something that only humans have. What physical, observable characteristic could humans possibly evolve that another animal couldn't evolve too? What if the image of God is purely spiritual, with no physically observable traces in the fossil record? Something that God alone "breaths" into beings of his choice. Something "that is not of blood or of the will of the flesh or of the will of man, but of God" as John said.

 

[gluadys]

Hi Papias
Actually we get about 2.9 billion alleles from each parent (one for each base pair).

Sorry, Brent, but I think you err in this. You are equating "allele" with base pair. But an allele is a version of a gene and any one allele will have hundreds of base pairs.

So we get about 25,000 alleles from each parent, not 2.9 billion.

And I expect Papias meant that we get 1 allele of each gene from each parent, which is also true.

With each generation the genetic contribution of the previous generation is halved. The genetic contribution of that original parent is reduced the factor, 1/2^n where n is the number of generations. After 1 generation it's 1/2, after 2 it's 1/4, 3 is 1/8, 4 is 1/16 etc.

It's not quite that simple. It is true that we get exactly half of our genes from each parent, because the genes are located on chromosomes and the way chromosomes are separated during meiosis guarantees we get one of each pair of chromosomes from each parent.

But it does not follow that we necessarily get 1/4 of each grandparent's set of chromosomes (or genes or alleles). The assortment of chromosomes derived from each maternal and paternal grandparent is unique to each ovum or sperm produced. In addition, chromosomal rearrangement regroups alleles still further, putting some alleles originally derived from a paternal grandparent on the same chromosome as some derived from a maternal grandparent.

In a large population, it is likely that the average rate of inheritance from each grandparent will approach 25% (ditto with the other fractions), but in any one individual the percentage of genetic material inherited from each grandparent can vary enormously. While it is improbable that it would be 0% for a grandparent, it is quite possible that you have no alleles at all from one of your great-grandparents. Their chromosomes just didn't happen to make it into the assortment of chromosomes which were bequeathed to you. (A sibling, on the other hand, might have some.)

This is one of the features of inheritance which make genetic drift possible.

 

[bdfoster]

Sorry, Brent, but I think you err in this. You are equating "allele" with base pair. But an allele is a version of a gene and any one allele will have hundreds of base pairs.

So we get about 25,000 alleles from each parent, not 2.9 billion.

And I expect Papias meant that we get 1 allele of each gene from each parent, which is also true.





It's not quite that simple. It is true that we get exactly half of our genes from each parent, because the genes are located on chromosomes and the way chromosomes are separated during meiosis guarantees we get one of each pair of chromosomes from each parent.

But it does not follow that we necessarily get 1/4 of each grandparent's set of chromosomes (or genes or alleles). The assortment of chromosomes derived from each maternal and paternal grandparent is unique to each ovum or sperm produced. In addition, chromosomal rearrangement regroups alleles still further, putting some alleles originally derived from a paternal grandparent on the same chromosome as some derived from a maternal grandparent.

In a large population, it is likely that the average rate of inheritance from each grandparent will approach 25% (ditto with the other fractions), but in any one individual the percentage of genetic material inherited from each grandparent can vary enormously. While it is improbable that it would be 0% for a grandparent, it is quite possible that you have no alleles at all from one of your great-grandparents. Their chromosomes just didn't happen to make it into the assortment of chromosomes which were bequeathed to you. (A sibling, on the other hand, might have some.)

This is one of the features of inheritance which make genetic drift possible.

Yes, Brent humbly retracts most of what he said in that paragraph. But the fact that it's not just a simple 1/2^n was the point. It's not that simple and genetic markers indicating ancestry do persist.

 

[Willtor]

I'm torn between 3 and 4. I didn't vote for 4 because it was worded in (what I perceived to be) a pejorative way. The essence of the revelation was that we were, at one time, in fellowship with God and we undermined that fellowship. As to the historical events in themselves, it might have been gradual, but it happened to all peoples. So I voted for 3.

 

[Marshall Janzen]

I voted for "All of the human race at the time", but with the caveat that it's actually speaking of a much larger period of time than a single generation.

The comparison I usually use is to the woman Jerusalem in Ezekiel 16. In one sense, that woman represents the long history of the nation of Israel. In another sense, any Israelite could see how their own life re-enacted that story to some degree. I think Adam in the Eden narrative carries the same two senses. Adam's story is both the long story of early humanity compressed into a tight narrative, and the story of each one of us.

 

[gluadys]

Yes, Brent humbly retracts most of what he said in that paragraph. But the fact that it's not just a simple 1/2^n was the point. It's not that simple and genetic markers indicating ancestry do persist.

Yes, the genetic markers are the key. Have you read about the Human Genomic Project that is using such markers to determine the relationships of different peoples and the pathways of their migration? I have a little book on it called "Deep Ancestry" that explains the various ways of tracking genetic markers and some of the discoveries they have made. Fascinating stuff.

 

[gluadys]

I voted for "All of the human race at the time", but with the caveat that it's actually speaking of a much larger period of time than a single generation.

The comparison I usually use is to the woman Jerusalem in Ezekiel 16. In one sense, that woman represents the long history of the nation of Israel. In another sense, any Israelite could see how their own life re-enacted that story to some degree. I think Adam in the Eden narrative carries the same two senses. Adam's story is both the long story of early humanity compressed into a tight narrative, and the story of each one of us.

I decided to ignore the pejorative tone and vote for 4, but basically I agree with what you say here.

 

[Papias]

Brent wrote:

Thanks for the thorough post. It is well thought out and has a lot of information. I will try to do it justice in response.

You did. Thanks! It’s nice to have an actual, informed and rational discussion on a message board instead of the PRATTS and evasion too often seen.

I think our main difference is not over math (thank God, I'm retired; I try to do as little math as possible!) but over the details of how lineages propagate.

The lineage of sexually reproducing organisms can be represented by a family tree. The "tree of life" showing the relationship of all life, is a massive family tree. After a lineage has split, no organism can go back and be ancestral to a branch that it doesn't occupy.

You mean “split” as in speciate, right? Then I agree. Otherwise it rejoins through mating, or doesn't rejoin.

Humans and chimps may have a common ancestor but neither is ancestral to the other. All human races can interbreed. The existence of races indicates that there has been branching within the human lineage. But the isolation has not been long enough for speciation to occur and because of this, the branching is not as exclusive as it is further down on the tree of life. A human can go back and be an "ancestor" to members of another branch, but only if the isolation is removed.

Right. By “branching” here, you don’t mean “split” as in the previous paragraph, which is speciation. Am I reading you right?

No, this is not true. Each parent gives 2.9 billion alleles to it's offspring.

Gluadys has corrected this. Yes, I meant that each parent gives 23,000 alleles, one per gene locus, each made up of many base pairs.

With each generation the genetic contribution of the previous generation is halved. The genetic contribution of that original parent is reduced the factor, 1/2^n where n is the number of generations. After 1 generation it's 1/2, after 2 it's 1/4, 3 is 1/8, 4 is 1/16 etc. The denominator doubles after each generation. After dozens of generations the allelic contribution of the original parent would indeed be negligible by this reasoning.

Ignoring Gluadys’ minor quibble (because, on average, the halving is a decent approximation over a large sample size over time)., we agree on the halving.
To see my point, simply continue your series. Remember, we have 23,000 genes/alleles. So, follow this table:

# Generations # of alleles from a single given ancestor
1 11,5000 (=50%)
2 ~6,000 (=25%, with me so far?)
3 ~3,000 (=13%)
4 ~1,500 (etc.)
5 ~750
6 375
7 ~ <200
8 ~100
9 ~50
10 ~25
11 ~13
12 ~7
13 ~4
14 ~2
15 ~1
16 Only a 50/50 chance of having even 1 left
17 1 in 4 chance of having even 1 left
18 1 in 8 chance of having even 1 left
19 1 in 16 chance of having even 1 left
20 And so on.

The point isn't that after 14 generations they have exactly 2 alleles from that ancestor, or such - of course the actual numbers vary quite a bit. The point is that after a long time, say 30, or 50, or 110, generations, it's quite reasonable that there'd be nothing, no trace, left. This isn't homeopathy, where some trace can survive impossible dilutions and still be there. And, of course, that this many generations happen very quickly. 30 geneations is just 700 years or so, and that's less than the time between 80,000 years ago and 79,000 years ago.

But as you pointed out, inheritance is not by mixing. Whole genes are transferred, and if a gene codes for a useful trait it will be preferentially retained. The 23,000 or so genes that make up the human genome are the genetic remnants of ancestors that lived billions of years ago. Anyone in a thousand years who claims to be a mayflower descendant better have the DNA to show it, because genetic markers indicating ancestry do persist.

No, they don&#8217;t, as the numbers above have shown. The halving is very strong, and kills them quickly &#8211; the math below takes this beyond 20 generations.
Consider one Ancestor (say our ancestor Khafra. After just 3,000 years, using 25 years as an average generation, that&#8217;s 3,000/25=120 generations. So by 1/2^n, that&#8217;s 1/(2^120)=1/(1.3X10^36). So times the number of alleles gives the number of alleles, on average, a descendant of Khfra has after 3,000 years. So 23,000/(1.3X10^36) = 1.7X10^-33, which is zero. In fact, doing the same for just 20 generations (500 years), gives 23,000/(2^20) = 23,000/(1 million) = 0.2, so, on average, after 20 generations, you&#8217;ve only got a 2% chance of having even a single gene left from a single chosen ancestor just 500 years ago.
The upshot is that genetic markers indicating ancestry do not persist if the ancestry is not a big chunk of your ancestry. Sure, selection and other factors can change this, but they can change it either way, either making sure some genes persist (like those for better brains), or removing whichever genetic chunk you are using as a marker. The bottom line is that markers are sufficient, but not necessary, factors in determining ancestry.

(OK, now I see your retraction and Gluadys' response. Gluadys, and Brent, do either of you see any way a marker can persist from one ancestor out of many million (say, from a lone Asian migrant to Europe 1000 years ago), without being protected by selection?

Yes you are definitely right about that. And assuming a nice well-behaved population with nothing to do but procreate, your math is inescapable. Of course to get years you have to assume a number of years per generation. But that's perfectly reasonable.

Yep, we agree. For instance, I&#8217;m about 1/32nd Native American, but I look pretty white.

There are a number of problems with this. First you seem to be equating number of descendants with an assurance that those descendants will penetrate every human lineage.

Only where travel allows them to do so. Eurasia has been genetically able to mix for millennia (see here, for example Silk Road - Wikipedia, the free encyclopedia ). Remember that in all of these examples, you have centuries for even one descendant to get to a new area, and once he or she does, practically that whole population becomes descendants within a thousand years or less.

 

[Papias]

This has not happened in the past for a number of reasons. Of course it may in the future because all humans can interbreed and air travel is removing geographic barriers that once caused genetic isolation. Yes Khafra probably had a few kids. And maybe one of them sailed to South America on a raft. But more likely the people the Spaniards found there (who probably were descendents of Khfra!) got there by another route. A route that involved migrations through Asia and probably north America. Migrations like that, and the genetic legacy they leave behind are increasingly the subject of DNA studies. Khafra probably was not ancestral to the aboriginal people of North and South America at the time of their first contact with Europeans.

I agree that the new world probably had no genetic contact for 10,000 years before 1492 (ignoring Kennewick man and such), and so Khafra was not an ancestor to the Native Americans and Aboriginies (though he is to many of them now).

Repeated DNA studies have shown that dogs are NOT descended from coyotes. ………….pack. Many of her dogs are most definitely descended from coyotes! ……….does not change the fact that dogs are NOT descended from coyotes. No matter how hard they tried and are still trying, coyotes have failed to leave their DNA in the dog genome.

I agree with all of this, and it means that within a few thousand years, nearly all dogs (except some kept in purebred lines) will have at least a few coyote ancestors, due if nothing else to your friend’s pack.

I don't share your opinion that it is trivially easy for a persons descendents to populate other continents and islands. Of course it is now with air travel and modern shipping.

I was talking about our descendants, so we agree.

But before the age of exploration, ocean travel was a major barrier to human migration. The indigenous human populations of the New World, Australia, and Pacific Islands were isolated for significant periods, prior to their first European contact.

Yes I agree. Rational thought happened much earlier than any of those colonizations.

OK, it seems to me the bottom line is, if Adam was born 80-100,000 years ago in Africa, then yes all humans are probably biologically descended from him.

Not just probably, but inescapably. It seems we agree here.

If Adam was a Neolithic farmer in Mesopotamia, the indigenous populations of the New World were NOT his descendants at the time of first European contact.

I agree. Adam, the first ape-human transitional capable of rational thought and therefore of rational subservience or rebellion wrt God, was well before the Neolithic.

You seem to equate humanness (image of God?) with the onset of rational thought, or some characteristic of humans that is genetically inheritable.

Yes, I do. That’s what I think “made in God’s image” means – rationality. It certainly doesn’t mean “having eyeballs” or “having hands”, as those are simply anthropomorphizations.

What if dolphins evolved rational thought?

I have no idea what that would result in. I’ll leave that up to God, as I agree it could certainly happen.

OK you could always think of some other criteria for humanity that dolphins don't have. Something that only humans have. What physical, observable characteristic could humans possibly evolve that another animal couldn't evolve too?

I see no reason to assert that no other animal could evolve to the point where God grants them souls. In fact, perhaps that is already God’s plan? I don’t know of everything that God is up to.

What if the image of God is purely spiritual, with no physically observable traces in the fossil record? Something that God alone "breaths" into beings of his choice. Something "that is not of blood or of the will of the flesh or of the will of man, but of God" as John said.

I like the requirement for rationality because it is a real thing. If “soul” or “God’s image” was completely untestable – some vaporous, ethereal “we have spirit”, then how could we tell it simply wasn’t non-existent, a fabrication we dreamed up ourselves? After all, the invisible and the non-existent look very much alike. The idea that God granted at soul at the point of rationality is not my idea, btw, but is the view of many theologians.

Thanks for the good discussion, let’s see where we are now……

Have a good day-

Papias

P.S. wrt the recent posts in support of Adam being a whole population - while that could be true, the Ancestry discussion between Brent and I shows that it's unneccessary, and that a single individual (or couple, after all, Eve ate first, not Adam in the story), works just fine. A single individual seems to be more reflected in the text, both in Genesis, Romans, and elsewhere. Because of that, and because some people seem to really care that it's one individual, I tend to go along with that - it works for many, both literalist and rational.

 

[Marshall Janzen]

P.S. wrt the recent posts in support of Adam being a whole population - while that could be true, the Ancestry discussion between Brent and I shows that it's unneccessary, and that a single individual (or couple, after all, Eve ate first, not Adam in the story), works just fine. A single individual seems to be more reflected in the text, both in Genesis, Romans, and elsewhere.

I agree that there are plausible ways of jibing a literal, individual Adam with science as we know it today. For me, the reason for seeing Adam as representing humanity/me and the Eden narrative as being symbolic is due to how it reads and how it jibes with other parts of Scripture. (For instance, you note the importance of Eve, yet sometimes Paul refers to Adam in a way that seems to encapsulate them both. He also speaks of being in Adam, not descended from Adam. This fits well if Adam and Eve are symbolic, representative characters.) But, maybe that's a discussion for another time!