Multiple Origins & Evolution

[J_B_]

There are several other topics on the theme of "How important is it?", such as the fossil record, the age of the earth, etc. However, given it hasn't sparked much conversation (and I've gotten some suggestions why that is), I figured I'd skip ahead to a topic that might be more interesting.

In the discussion of amino acids & evolution, the possibility of multiple origins came up. Therefore, I'll ask: How important is descent from a single population to the evolutionary sciences?

 

[Warden_of_the_Storm]

Ummm... I want say not majorly important, because I don't see a way how evolution from a single population vs evolution from several populations would really make a huge difference to the theory of evolution.

 

[J_B_]

Ummm... I want say not majorly important, because I don't see a way how evolution from a single population vs evolution from several populations would really make a huge difference to the theory of evolution.

I don't either, but others may have a different opinion.

 

[essentialsaltes]

Not at all. Since even if there were multiple origins (as we discussed elsewhere), only one of those pedigrees has evidently survived to the present day.

 

[J_B_]

Not at all. Since even if there were multiple origins (as we discussed elsewhere), only one of those pedigrees has evidently survived to the present day.

Ah, well, let me clarify. My intent was to ask the question in the context of descendants surviving from more than one of those original populations.

Again, even in that context, I don't see why it would be a big deal for evolution.

 

[ottawak]

There are several other topics on the theme of "How important is it?", such as the fossil record, the age of the earth, etc. However, given it hasn't sparked much conversation (and I've gotten some suggestions why that is), I figured I'd skip ahead to a topic that might be more interesting.

In the discussion of amino acids & evolution, the possibility of multiple origins came up. Therefore, I'll ask: How important is descent from a single population to the evolutionary sciences?

It's not essential. It is entirely possible that life arose more than once and the lines merged or became extinct. But the evidence is reasonably good that whatever happened before, all existing life arose from a single population at some point.

 

[J_B_]

It's not essential.

Thanks.

It is entirely possible that life arose more than once and the lines merged or became extinct. But the evidence is reasonably good that whatever happened before, all existing life arose from a single population at some point.

That evidence being ... ?

 

[ottawak]

Thanks.



That evidence being ... ?

Genetics, mostly.

 

[J_B_]

Genetics, mostly.

That doesn't help me much. Can you be more specific?

 

[ottawak]

That doesn't help me much. Can you be more specific?

I'm not sure I understand what you want. Do you have any specific reason for doubting the scientific conclusion of common ancestry?

 

[J_B_]

I'm not sure I understand what you want. Do you have any specific reason for doubting the scientific conclusion of common ancestry?

I figured you would be able to articulate your reasons for accepting it. In terms of evidence I've not been given, I'll need to remain agnostic.

 

[ottawak]

I figured you would be able to articulate your reasons for accepting it. In terms of evidence I've not been given, I'll need to remain agnostic.

I can, but it would take many posts to explain and would depend on your background in basic college level math and genetics. In a general way I am confident in the conclusions of science generally represent the best work scientists can do, and no one else is offering anything better.

 

[The IbanezerScrooge]

I figured you would be able to articulate your reasons for accepting it. In terms of evidence I've not been given, I'll need to remain agnostic.

In a nutshell,

ALL extant life on the planet we have encountered, from the smallest singe-celled bacterium to the largest animals on Earth, all of them have DNA that works pretty much the same way, uses the same chemical compounds, same peptides, same machinery to replicate, etc. Plants, animals, fungi, everything works the same way at the cellular level. We find the same conserved sequences of that DNA in bacteria that we do in much more complex animals. There are exceptions here and there, but overall, it's all fundamentally the same. So, the conclusion is that all extant life diverged from common precursors.

Could there have been multiple starts and lineages of organisms in the past? Sure, but there is little evidence that any of those other possible lineages continue to exist today. So, the consensus of data is that all life we know of on the planet comes from a common ancestor.

 

[Aussie Pete]

There are several other topics on the theme of "How important is it?", such as the fossil record, the age of the earth, etc. However, given it hasn't sparked much conversation (and I've gotten some suggestions why that is), I figured I'd skip ahead to a topic that might be more interesting.

In the discussion of amino acids & evolution, the possibility of multiple origins came up. Therefore, I'll ask: How important is descent from a single population to the evolutionary sciences?

It's the current favourite theory of evolutionists. Don't go down the track of asking where this single critter came from. They will tell you that it is irrelevant.

 

[J_B_]

ALL extant life on the planet we have encountered, from the smallest singe-celled bacterium to the largest animals on Earth, all of them have DNA that works pretty much the same way, uses the same chemical compounds, same peptides, same machinery to replicate, etc. Plants, animals, fungi, everything works the same way at the cellular level. We find the same conserved sequences of that DNA in bacteria that we do in much more complex animals. There are exceptions here and there, but overall, it's all fundamentally the same. So, the conclusion is that all extant life diverged from common precursors.

Thanks. I've heard this before. IMO it amounts to saying correlation is causation. Would you disagree with that?

I can, but it would take many posts to explain and would depend on your background in basic college level math and genetics. In a general way I am confident in the conclusions of science generally represent the best work scientists can do, and no one else is offering anything better.

You answered the OP, so thanks. I'm always willing to give it a try, but if you don't want to share more, or don't have anything to add to @The IbanezerScrooge that's fine.

 

[The IbanezerScrooge]

Thanks. I've heard this before. IMO it amounts to saying correlation is causation. Would you disagree with that?

In this case yes. It's not just seeing a few things and saying this is why. It's everything. I mean, sure it could all be a coincidence and nothing is as it seems, but what scientific justification would anyone have for that opinion? As I said it's the preponderance of the evidence and data that gives this consensus conclusion. It does not rule out that there may have been multiple starts and lineages, but none of those lineages are in evidence today, so we can't say that it occurred.

 

[ottawak]

It's the current favourite theory of evolutionists. Don't go down the track of asking where this single critter came from. They will tell you that it is irrelevant.

It is. Even if God poofed it into existence, evolutionary biology would still be the same.

 

[The IbanezerScrooge]

It's the current favourite theory of evolutionists. Don't go down the track of asking where this single critter came from. They will tell you that it is irrelevant.

It is. Even if God poofed it into existence, evolutionary biology would still be the same.

And if that's where the argument stopped that would be fine, except that creationists usually try and go on making Genesis 1 and 2 into literal history, which has scientific consequences. Science can test those claims at that point and we can look for what we would expect if those claims were true. An orchard model of diversity or a flood layer in geological data. We don't see corroborating evidence for those claims, so they are falsified and rejected.

 

[ottawak]

Thanks. I've heard this before. IMO it amounts to saying correlation is causation. Would you disagree with that?

Yes. From the scientific standpoint, correlation is confirmation, because science is descriptive, not prescriptive. Although scientists loosely speak of causality when they see subsequent related events, they are very careful not to assume it. With respect to common ancestry, it is a reasonable deduction based on projecting the evolutionary divergence we see back in time. And all (and I do mean all) of the evidence, fossil, genetic, evidence from related scientific fields, all of it is consistent with that deduction and none of it is inconsistent. That's all you are going to get, because that's all that science has to offer in any field.

 

[J_B_]

In this case yes.

Thanks.

It's not just seeing a few things and saying this is why. It's everything. I mean, sure it could all be a coincidence and nothing is as it seems, but what scientific justification would anyone have for that opinion?

Sure, what you mentioned is consistent with evolutionary theory. But if other possibilities exist, it seems better to me to remain agnostic on the issue.

... none of those lineages are in evidence today ...

This comment, however, leads me to believe there is still a misunderstanding. Whether yours or mine, I'm not sure. So let me lay something out.

Given life in our form exists, it's self-evident conditions were in favor of producing that form of life. For example, as I mentioned in my previous thread, conditions obviously favored the ~20 amino acids used by all known life. Maybe life using different amino acids originated at the same time, but we don't know because there's no evidence of it.

Given that favorability to our form of life, it seems possible multiple populations of our form could have originated, not just one population of our form. Had that occurred, what makes you think you could distinguish them?

There may be instances where biologists feel they can rule out multiple origins. For example, maybe common ERVs among a group of species is evidence of common origin. But do we really have such conclusive evidence for ALL species? My impression is no.