Evolution: common ancestor?

[Loudmouth]

If you equate evidence with assumptions, then yes, there's plenty of that.

Observations are not assumptions.

 

[Vaccine]

Since we have the endpoints of that process, it is actually interpolation, and not extrapolation. Also, we can compare genomes of different species to determine if the differences are consistent with the processes that cause change from generation to generation within species. This is called hypothesis testing, and it is a central part of the scientific method.

It's only interpolation if you assume evolution to prove evolution.
Another part of the scientific method is to eliminate all other possibilities. Koonin explained in a peer reviewed article how Convergent evolution is a better explanation for similar genomes than common ancestry. Seems comparative genomics does a lot of cherry picking and ignoring other possibilities to conclude common ancestry.

 

[Vaccine]

Observations are not assumptions.

In that case show me the complete transformation of one species into another.

 

[Loudmouth]

It's only interpolation if you assume evolution to prove evolution.

Do we have to assume guilt to get a DNA match at a crime scene? Do we have to eliminate the possibility of Leprechauns planting DNA at a crime scene before we can accept DNA as evidence?

Another part of the scientific method is to eliminate all other possibilities.

No, it isn't. The scientific method uses inference, not deduction. The scientific method can not eliminate Leprechauns planting evidence at crime scenes, and yet we still use forensic science in the courtroom.

Koonin explained in a peer reviewed article how Convergent evolution is a better explanation for similar genomes than common ancestry. Seems comparative genomics does a lot of cherry picking and ignoring other possibilities to conclude common ancestry.

Please, cite the article.

 

[Loudmouth]

In that case show me the complete transformation of one species into another.

"Boraas (1983) reported the induction of multicellularity in a strain of Chlorella pyrenoidosa (since reclassified as C. vulgaris) by predation. He was growing the unicellular green alga in the first stage of a two stage continuous culture system as for food for a flagellate predator, Ochromonas sp., that was growing in the second stage. Due to the failure of a pump, flagellates washed back into the first stage. Within five days a colonial form of the Chlorella appeared. It rapidly came to dominate the culture. The colony size ranged from 4 cells to 32 cells. Eventually it stabilized at 8 cells. This colonial form has persisted in culture for about a decade. The new form has been keyed out using a number of algal taxonomic keys. They key out now as being in the genus Coelosphaerium, which is in a different family from Chlorella."
Observed Instances of Speciation

 

[Dizredux]

Dizredux

On populations. Let me do a hypothetical. Say your family is descended from an Englishman who came over several hundreds of years ago, married several times and had children from each wife. He would be the last common ancestor for all descended from him. If you look before him at England there are thousands of ancestors in the English population that are related to him. You cannot point to any one of these and call him to be the LCA but you can refer to them as the ancestral population.

Resha

Sure, but what establishes the line of descent? Is it the paper trail of birth certificates or the observed traits that establishes them as descended from Englishmen? If it's the traits, then there must be some test that demonstrates Englishmen ... otherwise this becomes something like a "no true Scotsman" fallacy (which is oddly convoluted given that your example was about Englishmen).

For example, what if there were a hypothesis that a group of people descended from Englishmen because of their tea culture. Hmm. Well, China also has a tea culture, so why couldn't they be descended from the Chinese rather than the English? Now we have to separate English tea culture from Chinese tea culture, which becomes very difficult (I actually did a paper on this for a history class).

I was just doing a hypothetical as an illustration of a principle. Don't take where it was not meant to go, it isn't history.

Resah

I realize we're talking DNA here, but the problem is similar. That's why the thread on a synthetically larger alphabet is interesting. One argument for a common ancestor might be the possibilities for other alphabets (or other amino acids, etc.). Well, maybe. It would first need to be demonstrated that these other alphabets or amino acids would actually form naturally and produce sustainable life. Difficult to do. Or, it would need to be shown that other branches of life based on our 4-letter alphabet and 20-some amino acids have developed and then died out without contributing anything to the pool that continues on. Again, very difficult to do.

I am sorry but this does not make a lot of sense to me in the context of my statements.

Dizredux:

To elaborate a little, say life was able to get started a number of times. Many of these did not survive for one reason or another. The ones that did may have transferred genes between them. Somewhere in there is a population(s) that all life descended from.

Resha

Uh, yeah (above emphasis mine). As you move from individual to population to populations, at what point does it stop being LCA - stop being an idea with explanatory power - and become a statement that all life is descended from prior life. Duh.

Yes and that train of descent narrows down to a very small population that we are all descended from. Keep in mind that all known life on earth has the same kind of DNA. How else would you explain it except by common descent with a small ancestral population? The common descent/LCA concept works well and allows some good predictions which have held up. Do you have another evidence based way it could have happened?

Dizredux:

You asked about universal and common ancestor. What is known is that all of life that we know of shares the same genetic basis so it is reasonable to feel that they all came from, in some manner, a common ancestor be it individual, group, or groups. Actually, I think the LCA to be more statistical than anything else.

Resha

Very interesting. If LCA is just a statistical statement, that is something very different from how people seem to use LCA as a referant. It is something I could probably agree to.

What I mean by statistical is that you can define a point where all are seen as descended from that point. The same applies to Mitochondrial Eve ( matrilineal most recent common ancestor (MRCA) of all currently living anatomically modern humans,) That is also statistical in nature.

Resha:

I have no doubt all life stems from common processes. It's the part about a common ancestor that leaves me befuddled.

You might do some reading on Mitochrondial Eve. While not exactly the same, the dynamics on inheritance and determining the LCA/MRCA are similar.

Dizredux:

It is just too far back to tell much.

Resha:

Yeah, my opinion too. But I'm also a layman.

Interesting conversation,

Dizredux

 

[Dizredux]

Another part of the scientific method is to eliminate all other possibilities.

That is very much *not* a part of the scientific method. One of the bedrock principles is that you can never eliminate all other possibilities. There must always be left open the ideas that new information may come in to change the picture. All of science is provisional.

A small but very important point.

Dizredux

 

[Dizredux]

In that case show me the complete transformation of one species into another.

How about these for a start:
Observed Instances of Speciation
or these
Cases of Speciation

There are plenty more but first you perhaps need to show how these are not examples of speciation.

Dizredux

 

[Resha Caner]

Yes and that train of descent narrows down to a very small population that we are all descended from. Keep in mind that all known life on earth has the same kind of DNA. How else would you explain it except by common descent with a small ancestral population?

Have you tried to think about how else it might have happened? I have.

The common descent/LCA concept works well and allows some good predictions which have held up. Do you have another evidence based way it could have happened?

Yes and no. I've had extensive discussions on that topic with the biologists here at CF. I think there are possibilities (not ID related), but as I noted earlier, I'm not a biologist. So, the idea is a long way from something that would be published in Science, but it seems very plausible to me.

In one thread I asked the biologists here to rate the feasibility of some of the different points of the idea (there were roughly 10). From point to point the ratings varied from consensus to heated disagreement and from saying it was very possible to very unlikely.

 

[Resha Caner]

Now, when we talk about the process that gave rise to life, we assume it was a natural process. Why? Well, because we only have evidence of natural processes taking place. We have no evidence of unnatural processes or agents anywhere. In fact, 100% of the claims of supernatural causation that have been investigated, turned out to have natural causations 100% of the time.

It is a potentially lengthy digression, so I'll just say I have no reason to consider "unnatural" processes. At the same time, that doesn't exclude an intelligent agent. And there's the rub. If an intelligent agent played a role, how would you know it?

So we're not even made of exotic things. Creationists might have a case if we would have been build from some extremely rare isotope, or even one that doesn't actually exist naturally. But we aren't. Instead, we are made of the most common materials available.

The issue isn't so much exotic materials, but why was this particular arrangement of common materials selected when other possible arrangements were rejected?

I don't see why a chemical reaction would produce just one self-replicating molecule. I'ld expect it to create a whole bunch of it.

I agree, and that seems to point to multiple origin events, not one.

 

[Loudmouth]

It is a potentially lengthy digression, so I'll just say I have no reason to consider "unnatural" processes. At the same time, that doesn't exclude an intelligent agent. And there's the rub. If an intelligent agent played a role, how would you know it?

The same way we know that natural processes played a role, by looking at the evidence.

The issue isn't so much exotic materials, but why was this particular arrangement of common materials selected when other possible arrangements were rejected?

Who says they were rejected? Life simply started evolving from the first arrangement that was found.

I agree, and that seems to point to multiple origin events, not one.

Then why don't we see multiple genetic systems with different codons, different protein machinery, etc.? Of all the possible arrangements, why do we only see one?

 

[Resha Caner]

Who says they were rejected? Life simply started evolving from the first arrangement that was found.

Are you saying the alternatives never formed in the first place? There's evidence for that?

Then why don't we see multiple genetic systems with different codons, different protein machinery, etc.? Of all the possible arrangements, why do we only see one?

Um. You're just repeating the question I asked in earlier posts. Why aren't these supposed alternatives present? Do you know the reason why?

 

[Loudmouth]

Are you saying the alternatives never formed in the first place? There's evidence for that?

Why would life go back to non-life and start over again?

 

[Resha Caner]

Why would life go back to non-life and start over again?

I never implied it would.

 

[Loudmouth]

I never implied it would.

That is what life would have to do in order to use other alternatives, it would have to go back to non-life, and repeat abiogenesis. Once you set the foundation for basic genetic systems, there is no going back. For example, if you made major changes to codon usage in even simple bacteria the results would almost certainly be lethal. You would need to redesign the entire organism which evolution can't do, but designers can.

 

[Vaccine]

"Boraas (1983) reported the induction of multicellularity in a strain of Chlorella pyrenoidosa (since reclassified as C. vulgaris) by predation. He was growing the unicellular green alga in the first stage of a two stage continuous culture system as for food for a flagellate predator, Ochromonas sp., that was growing in the second stage. Due to the failure of a pump, flagellates washed back into the first stage. Within five days a colonial form of the Chlorella appeared. It rapidly came to dominate the culture. The colony size ranged from 4 cells to 32 cells. Eventually it stabilized at 8 cells. This colonial form has persisted in culture for about a decade. The new form has been keyed out using a number of algal taxonomic keys. They key out now as being in the genus Coelosphaerium, which is in a different family from Chlorella."
Observed Instances of Speciation

You know that isn't the same thing? That begins with a species of Chlorella and ends with a species of Chlorella. The challenge was to show the complete transformation of one species into another. Showing me algae speciating is not the same as showing algae evolving into protozoa.

That talk origin is in regard to a different topic. I mean, if that were the complete transformation from one species into another entirely different species, that's nobel prize material, that's unambiguous proof Darwin was right about the origin of the species, there would be no controversy. Think about that, the focus of that paper was about predator-prey systems, not speciation. Talk origins should have made that clearer that was in regard to something else.

 

[Vaccine]

How about these for a start:
Observed Instances of Speciation
or these
Cases of Speciation

There are plenty more but first you perhaps need to show how these are not examples of speciation.

Dizredux

Oh, those are speciation events, they just aren't the same thing as the complete transformation from one species into another.
As I said to loudmouth, those are not the same thing. Those begin with a species of X and ends with a new species of X. The challenge was to show the complete transformation of one species into another. Showing me algae speciating is not the same as showing algae evolving into protozoa.

That talk origin is in regard to a different topic. I mean, if that were the complete transformation from one species into another entirely different species, that's nobel prize material, that's unambiguous proof Darwin was right about the origin of the species, there would be no controversy. Think about that, the focus of that paper was about predator-prey systems, not speciation. Talk origins should have made that clearer that was in regard to something else.

 

[Vaccine]

Do we have to assume guilt to get a DNA match at a crime scene? Do we have to eliminate the possibility of Leprechauns planting DNA at a crime scene before we can accept DNA as evidence?

That's taking it to the extreme. You make it sound as if a scientist says it, that settles it. If something is true why stifle any inquiry?
Suggesting scientists should eliminate other possibilities, should be welcomed. What's wrong with some checks and balance?

No, it isn't. The scientific method uses inference, not deduction. The scientific method can not eliminate Leprechauns planting evidence at crime scenes, and yet we still use forensic science in the courtroom.

The scientific method doesn't infer facts. They use observable, testable, repeatable results to deduce empirical facts.
Hypothesis and theories make inferences. I don't mean inferences are bad, just that they can and should be challenged. Intelligent design theory uses the same method of inferences as the ToE.

Please, cite the article.

Similar sequences doesn't automatically mean common ancestry:
"The tests described above show that there is currently
no formal demonstration of the universal common
ancestry of the extant life forms. The likelihood tests of
the kind described by Theobald [4] fail to address the
problem because they yield results“
in support of common ancestry”
for any sufficiently similar sequences.
The alternative to UCA is convergent evolution of
highly similar sequences of the universal proteins (under
the convergence hypothesis, the phrase
“universally conserved”
becomes an oxymoron)"

I apologize, I didn't realize he went to the trouble of eliminating convergent evolution.

"We believe that together this evidence makes conver-gent evolution of the highly similar sequences in over
100 proteins that are confidently traced back to the
putative Last Universal Cellular Ancestor (a highly con-
servative estimate) [2] a virt
ual impossibility. However,
formal demonstration of UCA, independent of the
assumption that universally conserved orthologous pro-
teins with highly similar sequences actually originate
from common ancestral forms, remains elusive and
might not be feasible in principle."
http://www.biologydirect.com/content/pdf/1745-6150-5-64.pdf

Another alternative is common design, but he didn't consider that.

 

[Resha Caner]

That is what life would have to do in order to use other alternatives, it would have to go back to non-life, and repeat abiogenesis. Once you set the foundation for basic genetic systems, there is no going back. For example, if you made major changes to codon usage in even simple bacteria the results would almost certainly be lethal. You would need to redesign the entire organism which evolution can't do, but designers can.

I don't know what you think you're talking about, but this has no relation to my conversations with DogmaHunter and Dizredux.

 

[dysert]

Does anyone honestly think that these living organisms were alive in the pre-Big-Bang singularity?

Of course not. Why would we think that?

Correct me if I'm wrong, but isn't it postulated that all matter came from the Big Bang? And some billions of years later the earth formed? And some many millions of years later life on earth formed? If this chain of events is true, then life eventually formed from whatever came from the pre-Big-Bang singularity.