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Is common descent a fact?


cdowis

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Common descent with modification is one of the primary descriptions of biological evolution. It is a scientific theory (just as powerful as, if nor more so than, the theory of relativity) that has been and continues to be validated by empirical testing against physical observations along multiple lines of evidence.

(Gotta run, but had to get that in.)

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The overwhelming weight of relevant scientific evidence supports common descent. A large body of internally consistent evidence for common descent comes from biology, molecular biology, paleontology, genetics, geology, anthropology and physiology. The best evidence fora common ancestor for humans and chimpanzees comes from comparison of their respective genomes.

It turns out that we share some very interesting DNA sequences with the chimpanzee (and other great apes). These sequences were left in the genome of our common ancestor by viral infections that attacked germ line cells instead of, or in addition to, somatic cells. For those who may not know, certain retroviruses can inject their RNA into a host cell, which then transcribes it to DNA and proceeds to produce the proteins that are coded by these sequences. The foreign proteins collect in the host cell and eventually form new viral particles, which then leave the host cell to infect other cells.

When this happens with germ line cells, the inserted foreign DNA sequences can be inherited. That is, they are passed from generation to generation essentially unaltered. The fact that humans share several of these "fossil DNA" sequences with the chimpanzees for example (the exact same viral sequences in the exact same positions along the genome), is clear evidence that we share a common ancestor with the chimps.

This common ancestor (one individual at one point) acquired a germ line cell viral infection and the primate and hominid branches of the family share this DNA sequence yet today. This happened several times, and several times these foreign DNA sequences show up in our genome. This endogenous retrovirus story does not stop there. Scientists have now also tracked the co-evolution of viral strains with their hosts through long periods of time, using these germ line cell markers.

More importantly, the concept of common descent has tremendous predictive power. The Supernatural Creation hypothesis, aside from being untestable, has no predictive power whatsoever - none.

We could go on all day. There are great examples of this kind from each of the disciplines I mentioned above. And they form a remarkably consistent picture regarding the age of the earth and of our species. The take home message is common descent.

If someone wishes to argue that endogenous retrovirus data supports creationism or ID, then they are obliged to accept the notion that the Creator would go to the considerable time and effort to insert about half a dozen identical foreign DNA sequences into the genomes of both humans and some primates in exactly the same location along the genome. And since this "designer" is purported to be intelligent, the creationist should give a rational reason why such a designer would choose to do so.

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Contains information from one of my posts on another thread.

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If we are not all descended from the same ancestor(s), God sure made it easy on himself by doing things like using the same genes songbirds use for generating their songs that we do for speech.

Talk about efficiency...

Seriously, it's hard to imagine how we would NOT all be part of the same thread of life.

Of course that does not mean that God does not exist- it has nothing to do with that.

http://www.the-scientist.com/blog/display/57266/

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It appears to me that the evidence for "common decent" could also be used as evidence for a common creator (or designer, if you will).

What?

I invite you to think about this statement again, and then try to explain how it makes any sense at all.

Please explain how the evidence for common descent supports a creator.

The whole point of the discussion is to demonstrate common descent as a reality as opposed to magical creation.

If you now claim that common descent supports magical creation, you have some explaining to do. Please cite the relevant scientific data in your attempt.

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It appears to me that the evidence for "common decent" could also be used as evidence for a common creator (or designer, if you will).

No really. Not once you look at the details.

There are books and books full of facinating evidence unfolded like detective work and cross-correlated, fitting like a jigsaw puzzle whose picture is clear. One of my favorite examples is explained in a good wiki article:

Clear evidence for the evolution of Homo sapiens from a common ancestor with chimpanzees is the number of chromosomes in human as compared to all other members of Hominidae. All Hominidae with the exception of humans have 24 pairs of chromosomes. Humans have only 23 pairs. Human chromosome 2 is widely accepted to be a result of an end-to-end fusion of two ancestral chromosomes.[10][11]

The evidence for this includes:

The correspondence of chromosome 2 to two ape chromosomes. The closest human relative, the common chimpanzee, has near-identical DNA sequences to human chromosome 2, but they are found in two separate chromosomes. The same is true of the more distant gorilla and orangutan.[12][13]

The presence of a vestigial centromere. Normally a chromosome has just one centromere, but in chromosome 2 there are remnants of a second centromere.[14]

The presence of vestigial telomeres. These are normally found only at the ends of a chromosome, but in chromosome 2 there are additional telomere sequences in the middle.[15]

Chromosome 2 thus presents very strong evidence in favour of the common descent of humans and other apes. According to researcher J. W. IJdo, "We conclude that the locus cloned in cosmids c8.1 and c29B is the relic of an ancient telomere-telomere fusion and marks the point at which two ancestral ape chromosomes fused to give rise to human chromosome 2."[15]

Now, just in case the astounding significance of this doesn't quite sink in, please check out this bit of a lecture:

or here

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I suppose one would have to decide if the number of "shared genes" proves evolution or not.

According to this, we share 99% of our genes with mice. Not chimps, mice.

I of course believe in evolution in one form or another so I have no problem with that.

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just out of curiosity (it's a morbid fascination with me):

What does it take to have 2 chromosomes fuse? Is it viral degradation? Environmental interference? Electromagnetic wave radiation interference, etc?

What is the most genetically large creature science has discovered? Is 48 chomosoms fairly normal across all boundaries of the life on earth? Are there any other creatures that have a double prime genetic marker (23 from each parent)?

I'm not trying to argue the point, but their just some thoughts I've had that I never have been able to find an answer to.

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The whole point of the discussion is to demonstrate common descent as a reality as opposed to magical creation.

The very mention of "magical creation" is a pejorative term and simply indicates you are a literalist who has no understanding whatsoever of the nature of religion.

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44Foxtrot in quotes

<<<First of all, it sounds to me as if you are simply parroting material you read on a creationist or Christian apologist website somewhere. If you are trying to imply that viral DNA sequences from a single germline cell infection of a single common ancestor cannot be inherited and seen in the genome of humans today, then you are simply mistaken.>>>>

I suppose my so called parroting could be explained as some inherited characteristic

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just out of curiosity (it's a morbid fascination with me):

What does it take to have 2 chromosomes fuse? Is it viral degradation? Environmental interference? Electromagnetic wave radiation interference, etc?

What is the most genetically large creature science has discovered? Is 48 chomosoms fairly normal across all boundaries of the life on earth? Are there any other creatures that have a double prime genetic marker (23 from each parent)?

I'm not trying to argue the point, but their just some thoughts I've had that I never have been able to find an answer to.

For DNA to fuse, it could be a change in mRNA which could change the links between the nucleotides. Or it could be the result of an enzyme activation or change. Also a change in tRNA could reprogram DNA information.

See this video for an idea of possible mechanisms-

In order for this to create a new breeding population of a new species, there would have to be many individuals in a living breeding single generation that have had the same genetic change happen, creating the exact same genetic change-- all at once.

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I suppose one would have to decide if the number of "shared genes" proves evolution or not.

According to this, we share 99% of our genes with mice. Not chimps, mice.

I of course believe in evolution in one form or another so I have no problem with that.

Yeah, and when full genomes of other mammals are sequenced, we'll see a high number of similarities there, too. However, in my mind, what's more pertinent to this discussion is looking at the overall match of the genomes, not just the number of chromosomes or the shared number of genes. That same article you cited also mentions that the mouse genome is 14% smaller than the human genome with only 40% overlap. There is a much higher genomic correlation among the primates, and especially between chimps and humans.

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The theory of evolution (and it is a theory, so no, common descent is not a fact) is a fairy-tale for grown-ups. In the fairy-tale the frog turns into a prince in a split second, in the theory of evolution it happens more slowly. A fairy-tale is a fairy-tale no matter how you dress it up.

In one sense we are examples of common descent... we are all desended from Adam.

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The theory of evolution (and it is a theory, so no, common descent is not a fact) is a fairy-tale for grown-ups. In the fairy-tale the frog turns into a prince in a split second, in the theory of evolution it happens more slowly. A fairy-tale is a fairy-tale no matter how you dress it up.

In one sense we are examples of common descent... we are all desended from Adam.

And yet you have no objective evidence whatsoever to support your claims of supernatural creation. Without evidence, the creationist view becomes the fairy tale.

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The very mention of "magical creation" is a pejorative term and simply indicates you are a literalist who has no understanding whatsoever of the nature of religion.

Oh, I have an understanding of religion alright, especially the Mormon religion. I was born and raised in the Church, married in the temple and all the rest. It took me a while to figure it out. However, I now understand that the basic tenets of Mormonism are absolutely incompatible with science. And it is clear which of the two worldviews is supported by the evidence.

To the other point, why should you see the term "magic" as pejorative? Given the history of Joseph Smith and the role that magic and magical thinking played in the early Church and especially in bringing forth of the Book of Mormon (as described in exactly those terms and in some detail by Richard Bushman in Rough Stone Rolling), I would think that Mormons would embrace and defend the use of this term as applied to Mormonism.

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to demonstrate common descent as a reality as opposed to magical creation.

I think you are confused. The LDS do not accept the "poof" of creationism == there is no magic in the creation, but but simply the application of natural laws. As someone said, that modern technology would appear to be magic to primitive people.

If you want to talk about magic and poof, please go to some other religious forum and stop insulting us with your ignorant comments.

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Common descent with modification is one of the primary descriptions of biological evolution. It is a scientific theory (just as powerful as, if nor more so than, the theory of relativity) that has been and continues to be validated by empirical testing against physical observations along multiple lines of evidence.

(Gotta run, but had to get that in.)

You and Tarski may feel comfortable claiming that the theory of common descent has factual status on par with the laws of physics, and that is a common ploy in the biological sciences (resulting from an inferiority complex?). The problem is that such biological theories do not have the status of physical laws which (1) can be replicated in a laboratory setting, (2) can be verified by other forms of observation, (3) are not in conflict with known normative theories, and finally (4) are theoretically falsifiable. Biology is not a "hard" science, and all we have actually seen validated has been adaptation and natural selection. That doesn't take us to evolution.

In this immediate instance, not only does basic evolutionary theory contravene the Second Law of Thermodynamics (Entropy, which means both that spontaneous generation of life is impossible, and that mutations tend to be destructive) by imagining a logical sequence of descent which cannot be proved, based on an unobserved and unreplicated spontaneous generation of life, followed by a further spontaneous replication of, and sequential development of species through to homo sapiens sapiens -- as though there is a magical ghost in the machine!!

The theory of common descent may be true, but has not been demonstrated, and no known mechanism could overcome the difficulties: Not only those listed above, but the lack of intermediate forms which could link species in the required sequential order. That this is a major problem was well recognized a generation ago by Nils Eldridge and by the late Stephen J. Gould, who together formulated the theory of "Punctuated Equilibria" to account for the absence of transitional forms which the fossil evidence should long since have provided. Their theory provided for evolutionary change under stress over a relatively short period in an isolated area (thus not leaving huge quantities of fossils).

One of the reasons why the theory of intelligent design is so popular in some quarters is precisely because it doesn't seek to violate the known fundamental laws of the universe, and it also accords with what most hard scientists accept as the reasonable existence of sentient beings elsewhere in the universe, beings which have been around much longer than we have, and which would long since have been able to create life in some presumably complex forms. Indeed, we may be able to design and create actual life in the near future. Perhaps only technical limitations now prevent us from doing so.

We know that all life on Earth is based on a double-helix DNA blueprint. There might be other such blueprints in the universe, and ID need not be defined as a religious or magical belief. For, as the late Arthur C. Clarke liked to say, "Any sufficiently advanced technology is indistinguishable from magic" (Clarke's Third Law).

So far as I have been able to understand it, LDS doctrine doesn't actually distinguish between science and religion, and apparently opts for Transmission of life from one sector of the universe to another, so that "creation" is merely organization of worlds and the life thereon -- "terraforming," as it were -- and not creation from nothing. There was no beginning, and there shall be no end.

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Perhaps you are not aware that the mitochondrial DNA of every individual on earth for whom the analysis has been done can be traced to a single female progenitor who lived approximately 200,000 years ago. This "Mitochondrial Eve" was literally the "mother" of all humans so far tested.

Does this mean that the story of Eve is true, and does that give validity to the Genesis account?

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As a quick reference point, hominids diverged from ancient chimpanzees between about 5 and about 7 million years ago.

Molecular biology suggests the ancestral line leading to hominids and chimps (and bonobos) diverged around 7 to 9 mya (cf. Archaeology Odyssey, 5/6 [Nov-Dec 2002], 17).

We have the full bipedalism of Auroran already at ca. 6 mya, and Ian Tattersal points out that the dentition and hip bones are more like modern humans than Lucy's. That suggests a long history of development prior to that time.

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I think you are confused. The LDS do not accept the "poof" of creationism == there is no magic in the creation, but but simply the application of natural laws. As someone said, that modern technology would appear to be magic to primitive people.

If you want to talk about magic and poof, please go to some other religious forum and stop insulting us with your ignorant comments.

The idea that God uses natural laws to do his work is, again, a made up assertion backed by no evidence whatsoever. Without evidence, your claim, which I have heard before, can readily be dismissed as the imagining of superstitious folks who don't want to be left behind by science and so come up with a just so story about how God uses science and natural law to do his work.

I am very familiar with the Mormon claim that God accomplishes his work in accordance with natural law. This concept was famously articulated by Joseph Fielding Smith, and individual who also stated that man would never set foot on the moon. So much for prophetic competence, or the understanding of natural law for that matter.

You need to figure out what you believe. Do you believe that God is supernatural?

How can you believe that God uses natural law and then turn around and claim the existence of miracles?

How can you claim that God uses natural law and then attribute to God actions that clearly violate the natural laws he supposedly uses?

Only one who is woefully unaware of what natural laws allow and do not allow would make such statements in the context of what Mormons claim to believe about God.

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