Scientific Evidence for Universal Common Descent

[Subduction Zone]

..take it up with Science Magazine, Wiki, and innumerable articles on the subject. I have called it, from the beginning, the mtDNA 'marker', that indicates descent. Howls of ridicule and jeering went up over that.

The unscientific hysteria, and 'gotcha!' replies, only reinforce my perception that bluff, hysteria, and propaganda is used to support common descent.

Some terminology is ambiguous.. by design? ..Some, maybe. Lack of understanding about the many complex nuances in genetics.. that is still not completely understood by those in the fields.. ..is not an indicator of 'Deception!' 'Ignorance!' ..from those with a more informed opinion.

The 'Thou Fool!', 'Knave!', replies, that typify the hecklers and True Believers, are pretense.. pseudo science bluff, to fool the uninformed. They are not rational, scientific arguments.

You need to be able to quote from those magazines. They probably did not make the same gross error that you did.

EDIT: I found an article that uses that term. But it also makes the mistake of conflating Mitochondrial Eve with the Most Recent Common Ancestor:

mtDNA : The Eve Gene

Just because a poor source uses a term incorrectly is a very poor reason to keep using that term.

 

[Jim]

@Jose Fly Has anyone been able to simulate the Cambrian explosion, or anything like it, with any combination of speciation models?

 

[Subduction Zone]

@Jose Fly Has anyone been able to simulate the Cambrian explosion, or anything like it, with any combination of speciation models?

Interesting question. Did you know that the Cambrian explosion lasted for tens of millions of years? It was not nearly as rapid as creationists try to make out that it was and there was plenty of multicellular life before it began.

 

[Jim]

Interesting question. Did you know that the Cambrian explosion lasted for tens of millions of years? It was not nearly as rapid as creationists try to make out that it was and there was plenty of multicellular life before it began.

I’m not promoting any creation models, and I didn’t learn about the Cambrian explosion from any creation Web site. Actually I don’t have idea myself about how to model the history of species. Like I said, that looks to me like a job for paleontology, unfettered by any preconceptions about common ancestry.

 

[Jim]

However useful and plausible the premise of common ancestry might be, I don’t see that as a reason to impose it on models of natural history. Or rather, I don’t see that as a reason for vilifying people, and depreciating their character and capacities, if they don’t believe it.

 

[Jim]

The only reason I can see for presuming common descent is because no one has any better idea. But, is it any harder to imagine various lines of ancestry tracing back to separate émergences of life from non-life, than to imagine that they all came from the same one? Would the Cambrian explosion be any harder to explain that way, than by speciation from pre-Cambrian species?

 

[ImmortalFlame]

The only reason I can see for presuming common descent is because no one has any better idea.

Actually, it's because it's the only proposed explanation for all of the available facts we have discovered out how life reproduces, diversifies and has existed in the past. It's the conclusion of the research, not a prior assumption.

 

[Jim]

Actually, it's because it's the only proposed explanation for all of the available facts we have discovered out how life reproduces, diversifies and has existed in the past. It's the conclusion of the research, not a prior assumption.

Common descent is not an explanation in itself. It’s a premise on which the most popular, and possibly the most useful, explanations are based.

 

[ImmortalFlame]

Common descent is not an explanation in itself.

Actually, it is. When we look at the fossil record and genetics, common descent explains why they are the way that they are. Common descent is the conclusion of looking at what we see, not a prior assumption.

It’s a premise on which the most popular, and possibly the most useful, explanations are based.

That would be true if it were a conclusion already determined before looking at the facts, but that is the wrong way around. Common ancestry was concluded as a result of testing and observing the facts. Since then it has become a model with which we can make successful predictions about facts and produce testable outcomes.

 

[Jim]

I’ll revise what I said. The idea of common descent might have started as a way of explaining similarities between species.

Common descent - Wikipedia

[15] Kant 1987, p. 304: "Despite all the variety among these forms, they seem to have been produced according to a common archetype, and this analogy among them reinforces our suspicion that they are actually akin, produced by a common original mother."

In 1794, Charles Darwin's grandfather, Erasmus Darwin asked:

“[W]ould it be too bold to imagine, that in the great length of time, since the earth began to exist, perhaps millions of ages before the commencement of the history of mankind, would it be too bold to imagine, that all warm-blooded animals have arisen from one living filament, which the great First Cause endued with animality, with the power of acquiring new parts attended with new propensities, directed by irritations, sensations, volitions, and associations; and thus possessing the faculty of continuing to improve by its own inherent activity, and of delivering down those improvements by generation to its posterity, world without end?[16]”

The only research that it was based on when it was first proposed was an observation of some similarities between animal species.

 

[usfan]

I have decided to ignore a couple of the more hostile and voluminous posters, to protect my dainty psyche.

I don't like doing this, for a several reasons:
1. The ignored poster gets unlimited free shots and assertions, without any possibility of a rebuttal. This is the appeal, and a major benefit of heckling, & i don't like to see it rewarded.
2. A valid point may actually be made, or a sound argument is included with the heckling, but i don't see it. That gives the illusion that i can't answer the point, when i am ignoring the poster, not any points of reason.
3. Others do not know who or why i am ignoring someone, and may feel the ignored poster is the victim of censorship.
4. It is disrespectful, even if warranted. I do not like promoting hostilities, but prefer understanding.

But, if a poster continues, with a flood of posts driven by phony narratives, lies, or propaganda, ignoring is the lesser of the evils. I generally declare a jubilee every so often, and request a reset, in hopes that civil, rational discussion can take place.

I'm sorry to have to do this, and it is not a positive for understanding and open communication, but a person can only take so much abuse. Some forums will ban or censure heckling like this, while others allow more freedom. I can only adapt, with the tools at my disposal, and ignoring the more hostile posters is a last resort.

These 2 are ignored:
tas8831
Dan From Smithville

If either would like a reset, and attempt to reopen communication, ask another member to help. I am always ready to start anew, with a clean slate. I don't hold grudges, and i don't take the heckling seriously. It is a tactic for disruption, and is at enmity with knowledge. I understand that many people are 'triggered' by any criticism or examination of common descent, and cut people slack, because of the thorough, widespread indoctrination of this religious belief.

 

[Jim]

Actually, it is. When we look at the fossil record and genetics, common descent explains why they are the way that they are. Common descent is the conclusion of looking at what we see, not a prior assumption.

Maybe you’re using “common ancestry “ as a synonym for all of evolution theory. What I mean by “common ancestry” is the idea that humans and other species have common ancestors. That idea was first proposed before 1794, as a possible explanation for similarities between species.

Common ancestry was concluded as a result of testing and observing the facts.
Since then it has become a model with which we can make successful predictions about facts and produce testable outcomes.

Again, maybe you’re saying “common ancestry” when you mean evolution theory in general. I’m talking specifically about the idea that humans and other species have common ancestors.

 

[usfan]

An interesting part about the mtDNA: Since the mother passes it down, all living things that have the mtDNA can be traced. It has been discovered that ALL humans are related, now, & did not evolve separately, in different regions. At one time, evolutionists believed there were different origins for humanity. It was believed some evolved in africa, china, & perhaps n. europe, from similar but different ancestors. Peking man was one such 'link', & neanderthal was another. But since the advent of genetics, & especially the mtDNA, we now can prove ancestry through it. We now know that all living humans have the same ancestral mother.. the Mitochondrial Most Recent Common Ancestor. ..aka, mitochondrial Eve, or also called the 'eve gene'.

Some theorize an african & others a chinese origin, but they all agree that humans have clear evidence of common descendancy. A great many people still have the neanderthal genes, as well, which challenges the previous theory of them being a different species. Since they could interbreed with other humans, they were likely just another tribe of homo sapiens, with only morphological differences. We have a lot of that today, even in fairly close proximity. You have tall africans & pygmies, which are very different morphologically, but have plainly evident genetic relation.

Here are a couple of decent graphics on mtDNA.

There are many implications and conclusions we can now make, based on fact, not conjecture or 'looks like!' subjectivity. I can make a list of some, if there is interest. But the discovery of mtDNA, and the mitochondrial Most Recent Common Ancestor, has been HUGE. It has changed forever the beliefs and flawed assumptions that are inherent in common descent.

 

[Polymath257]

There are many implications and conclusions we can now make, based on fact, not conjecture or 'looks like!' subjectivity. I can make a list of some, if there is interest. But the discovery of mtDNA, and the mitochondrial Most Recent Common Ancestor, has been HUGE. It has changed forever the beliefs and flawed assumptions that are inherent in common descent.

Actually, no. It has been a relatively minor piece of information.

Let me give a simplified scenario. Suppose you have a population of 100 females to begin with. Suppose at each generation, each female produces two children. Lets also assume that there is a 50% chance any child will be male and a 50% change it will be female.

Now, what happens after one generation? Well, 25% of the females will produce two males. These are dropped off because they have no *female* descendant. Next, 50% will have one male and one female. Finally, 25% will have two females. On an average, the population of females stays the same, but at each generation 25% have no further male heir.

Here's a question: how many generations does it take before everyone alive is a descendant through the female line from only one of the original females? Does this mean nobody is a descendant of the other females at all?

 

[usfan]

I saw this explanation for chromosome numbers, and thought others might find it informative. He is a definite proponent of common descent, but he explains dna fairly well.

Basics: How can chromosome numbers change? | ScienceBlogs

And BTW, i liked this guy's communication skills. Even though he misses some important things, he does explain the DNA pretty well.. in good layman terminology. Unfortunately, he glosses over some pretty important parts, like the splits & alleged rejoins at the centromere level. But the basic drawings of dna, & the explanations of the terms & definitions are pretty good. IMO, there is quite a bit of misunderstanding about genetics. It is not a 'lego block' of genes, assembled together to form different organisms. And, they don't randomly change, or split, or mutate into a new organism, or many of the things popularized in sci fi writings, movies, & imaginations. DNA is pretty tough. It makes high walls, so that an organism can ONLY be what its parents were. There is no 'hopeful monster' with genetics. The actual science, experiments, & conditions of the DNA make the ToE more implausible & fantastic every day.

 

[ImmortalFlame]

Maybe you’re using “common ancestry “ as a synonym for all of evolution theory. What I mean by “common ancestry” is the idea that humans and other species have common ancestors. That idea was first proposed before 1794, as a possible explanation for similarities between species.

But the idea didn't lead the facts, the facts lead to the idea. It took the discovery of evolution to put the missing pieces in place, but once the picture was more complete common ancestry became the answer. There was no pre-conception to expect common ancestry.

Again, maybe you’re saying “common ancestry” when you mean evolution theory in general. I’m talking specifically about the idea that humans and other species have common ancestors.

No, I am speaking specifically about common ancestry.

 

[usfan]

Actually, no. It has been a relatively minor piece of information.

Let me give a simplified scenario. Suppose you have a population of 100 females to begin with. Suppose at each generation, each female produces two children. Lets also assume that there is a 50% chance any child will be male and a 50% change it will be female.

Now, what happens after one generation? Well, 25% of the females will produce two males. These are dropped off because they have no *female* descendant. Next, 50% will have one male and one female. Finally, 25% will have two females. On an average, the population of females stays the same, but at each generation 25% have no further male heir.

Here's a question: how many generations does it take before everyone alive is a descendant through the female line from only one of the original females? Does this mean nobody is a descendant of the other females at all?

Some important points and facts about mitochondrial MRCA:

1. The mt-MRCA is the 'most recent', not necessarily the first, or only woman. That is unknown, and can only be speculated.
2. ALL human beings alive today, and all dna from the dead are shown to be descendants of the mt-MRCA.
3. Whether there were other women around, or other lineages, is unknown and speculated. We only know of this one.

And you are quite wrong about the significance.

1. Theories about regional evolution of man are debunked. All of humanity has descended from the same SINGLE woman. (Actually, her relationship status is unknow . .. maybe she was married! )
2. Some races or people groups are not 'lower' or 'higher', on the evolutionary scale than others. We are all fairly recent descendants, and share a common genetic past. Eugenics and white supremacy is debunked.
3. There is no empirical evidence that this mt-MRCA descended from anyone else, apes, chimps, or some other mythical hominid. That is speculation.
4. The consistency and regularity of humans, since this first mitochondrial woman, does not indicate 'evolution!', or any movement up or down an imaginary evolutionary scale. We have not changed, genetically. We are all from the same, original haplogroup of humankind. There are no others.

 

[Polymath257]

Some important points and facts about mitochondrial MRCA:

1. The mt-MRCA is the 'most recent', not necessarily the first, or only woman. That is unknown, and can only be speculated.

It is false that it can only be speculated. We know that there was never a bottleneck in the human population to the extent that there would have been only one female.

2. ALL human beings alive today, and all dna from the dead are shown to be descendants of the mt-MRCA.

And the same is true of Y-chromosome Adam. Yet they lived at very different times.

3. Whether there were other women around, or other lineages, is unknown and speculated. We only know of this one.

A repeated claim, but still wrong.

And you are quite wrong about the significance.

1. Theories about regional evolution of man are debunked. All of humanity has descended from the same SINGLE woman. (Actually, her relationship status is unknow . .. maybe she was married! )

Actually, even the separate evolution models are consistent with mt Eve. So no, this does NOT exclude them.

2. Some races or people groups are not 'lower' or 'higher', on the evolutionary scale than others. We are all fairly recent descendants, and share a common genetic past. Eugenics and white supremacy is debunked.

They were debunked LONG before mtEve.

3. There is no empirical evidence that this mt-MRCA descended from anyone else, apes, chimps, or some other mythical hominid. That is speculation.

And this is false. The exact same type of analysis of mtDNA can give the female-line MRCA of humans and chimps or humans and other primates. To say this is speculative is to deny the exact methods that lead to our discovery of mtEve in the first place.

4. The consistency and regularity of humans, since this first mitochondrial woman, does not indicate 'evolution!', or any movement up or down an imaginary evolutionary scale. We have not changed, genetically. We are all from the same, original haplogroup of humankind. There are no others.

Um, this is no way negates evolution that happened prior to mtEve. In fact, the same techniques can be used to help us understand the details of said evolution.

 

[Polymath257]

I saw this explanation for chromosome numbers, and thought others might find it informative. He is a definite proponent of common descent, but he explains dna fairly well.

Basics: How can chromosome numbers change? | ScienceBlogs

And BTW, i liked this guy's communication skills. Even though he misses some important things, he does explain the DNA pretty well.. in good layman terminology. Unfortunately, he glosses over some pretty important parts, like the splits & alleged rejoins at the centromere level. But the basic drawings of dna, & the explanations of the terms & definitions are pretty good. IMO, there is quite a bit of misunderstanding about genetics. It is not a 'lego block' of genes, assembled together to form different organisms. And, they don't randomly change, or split, or mutate into a new organism, or many of the things popularized in sci fi writings, movies, & imaginations. DNA is pretty tough. It makes high walls, so that an organism can ONLY be what its parents were. There is no 'hopeful monster' with genetics. The actual science, experiments, & conditions of the DNA make the ToE more implausible & fantastic every day.

Show evidence of 'high walls' around DNA.

 

[usfan]

Calling mutations of genes, 'New Genes!', is like wrecking your car, and calling it a 'New car!'

Mutations do not 'create!' new genes. They cannot produce increased complexity, make warm blood cold, scales to feathers, fins to legs, or any of the sci fi imaginations about mutations that fill the public perception.

Mutations are deleterious, or barely survivable at best. They 'create!' nothing.

The mutation rate, or the mitochondrial clock, has been measured, by exhuming remains of known ancestors, and comparing the mtDNA with living descendants. The Russian Romanovs were part of this rate calculation.

NONE of the mutations within the genome have altered the basic genetic structure. DNA repairs itself, and any major aberration in a mutation is fatal to the gene, and the organism. It does not produce 'positive' traits, and is not the engine of common descent, as so many belueve. Mutation has never been observed, to increase complexity in an organism, it is just speculated and assumed.