Alan,
thanks again!
the mindset of these people is by far harder to understand that general relativity!
DNA and Man's origin
by D wiltshire 126 Replies latest jw friends
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MYOHNSEPH
the evidence is so overwhelming already that it is amazing to me that people still deny evolution.
Funny thing, evidence. Sometimes two people can take the same evidence and use it to support two completely different arguments. And no matter how much of it you gather, you always wonder if you missed some. Sometimes, what may seem to be overwhelming evidence, can lead to a completely wrong conclusion. When I was about ten years old, one of my morning chores on the farm was to go out and milk the cow. We had an old cow which had a most irritating habit. As soon as I would sit down on my stool and begin milking her, she would start swishing her tail, right into my face. On a particular morning I decided I had had enough of that and I devised a remedy for the problem. I took a little piece of string out of my overall pocket, placed the milking stool behind the cow and tied the string to the cow's tail. I stood up on the stool, pulled the cow's tail up over my head and was about to tie it to a wooden rafter above the cow's stall. Just about the time I had the string thrown over the rafter and the cow's tail pulled up as high as I could get it, the one good strap on my overalls broke and my overalls fell down around my feet. As fate would have it, at that very instant, my father walked through the barn door. I never was able to convince him I was just trying to milk that cow. I guess the evidence was just too overwhelming!
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Realist
MYOHNSEPH,
the problem is that most people have no idea what evolution actually is, what DNA is and how mutations arise. they have no idea what facts are known and they no nothing about how science works.
i found that it is completely pointless to discuss this matter with people who have no interest in an scientific discussion.... since their ideas are merely based on faith and not on facts...and they refuse to consider alternative hypothesis.
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Earnest
Have I missed something ? Just what does DNA establish about man's origin ?
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AlanF
I'm not sure what D Wiltshire meant, Earnest, but I'll give you a bit of my understanding of it.
The DNA of all macroscopic life has a great deal in common. DNA is full of what are called "junk sequences" and "junk genes" that have no apparent function, but are extremely similar in apparently dissimilar species. This indicates a common origin via evolution, but is extremely difficult to understand as the product of an efficient Creator.
Some of these "junk genes" are expressed from time to time. When whaling was common, from time to time a whale would be landed that had hind legs in various states of development. Some were complete with bones, muscles and so forth. This shows that genes for legs are still in the whale's DNA. This is an extremely strong indication that whale ancestors had legs -- otherwise why would the genes for legs still be there? Biologists did some experiments with growth hormones on chicken embryos some years ago. The result was that the chicken embryos developed tooth buds, which indicates that genes for teeth are still resident in bird DNA, even though the last toothsome birds seem to have disappeared 60-70 million years ago. Humans have about 98% of their DNA common with chimpanzee DNA, complete with the "junk genes". This is extremely strong circumstantial evidence for a common ancestor.
AlanF
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MYOHNSEPH
i found that it is completely pointless to discuss this matter with people who have no interest in an scientific discussion.... since their ideas are merely based on faith and not on facts...and they refuse to consider alternative hypothesis.
I couldn't agree with you more! I also agree that scientific evidence should be examined honestly and objectively, regardless of it's impact on ideas and beliefs based solely on faith. In my opinion, the body of evidence, currently at our disposal, does indeed, and overwhelmingly, support the conclusion that life on earth has arrived at it's present state through an evolutionary process. What I am not entirely convinced of is that this process was set in motion purely by accident and has, through an unfathomable series contingencies, produced the intricate and delicate order of life we behold today. It's not a matter of faith. It's just the way my version of common sense works. But hey! Maybe I just need to get the upgrade!
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Earnest
Thanks, Alan.
The way I have reasoned about this is that the same building blocks (i.e. DNA) have been used for all life but that sufficient variation was contained within different species to allow for subsequent adaptation.
So you would never find animal DNA in plants which might cause them to grow legs, or plant DNA in humans that would have us grow leaves. But if circumstances changed then it is likely that all living matter can adapt to its environment. Does this mean I believe Adam and Eve is a true account ? I think the jury is still out on this but I had understood that DNA proved we all came from a common human ancestor. Is this true ?
Earnest
Edited by - Earnest on 15 February 2003 18:15:55
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Realist
MYOHNSEPH,
thank you for your very sensible reply!
What I am not entirely convinced of is that this process was set in motion purely by accident and has, through an unfathomable series contingencies, produced the intricate and delicate order of life we behold today.
there are actually many examples of new species forming right now. the requirement is that a species is seperated in 2 or more populations (this happens for instance when a few individuals from one species reach a new island but there are many other possibilities). than these seperated groups develop differently...and eventually look quite differently and cannot mate anymore with each other. no higher power is required for this to happen. its just an accumulation of mutations that are unique to the gene pool of the different groups.
a big still unanswered question is where the first cell came from...no one was able to reproduce all required steps so far...although some steps could be remodeled in the lab. however, since god apparently did not intervene at any point prior or at after the creation of the first cell it seems rather unlikely that the formation of the first cell was a result of him putting the parts togehter.
Earnest,
analysis of mitochondrial DNA suggests that all europeans come from i believe 5 (maybe it was 7) different females.
Edited by - realist on 15 February 2003 18:55:16
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AlanF
Hi Earnest,
: So you would never find animal DNA in plants which might cause them to grow legs, or plant DNA in humans that would have us grow leaves.
As I understand it, there's actually quite a bit of commonality between plant and animal DNA. It appears to be more a matter of degree than of kind, when you consider how genetically related various similar animal or plant species are to one another. The further apart the fossil record indicates the species are in time origin, in general the further apart the genes indicate they are. The is what the so-called genetic clock means. For example, frogs seem to have been around for some 300 million years, and the various frog species are much farther apart genetically than humans, chimps and gorillas are, or than dogs and bears are.
: But if circumstances changed then it is likely that all living matter can adapt to its environment.
If life evolved essentially on its own, then the fossil record demonstrates that that is the case.
: Does this mean I believe Adam and Eve is a true account ? I think the jury is still out on this but I had understood that DNA proved we all came from a common human ancestor. Is this true ?
DNA provides an extremely good indicator of this only for relatively modern humans. There is very good evidence that humans suffered an extreme bottleneck in population about 75,000 years ago, after the huge explosion of the volcano Tambora in Indonesia produced a sort of "nuclear winter" that precipitated another ice age cold spell and seems to have wiped out all but a thousand or so modern humans. A recent genetic study of Neanderthal remains indicated that they and modern humans are relatively distantly related -- and note the term "relatively". The controversial "mother Eve" theory is probably what you have in mind. Via "genetic clock" assumptions it pegs a common ancestor of modern humans at about 250,000 years ago. However, this theory is based on mitochondrial rather than normal DNA, and has been strongly challenged by many biologists. It's certainly not consistent with "population bottleneck 75,000 years ago" idea.
The main indication we have that humans evolved -- whether by standard evolutionary mechanisms or something else is still not solidly determined -- is the fossil record. There is a jerky sequence of fossils going back 5-6 million years now, and paleontologists are constantly finding new evidence that only bolsters the overall claim that mankind evolved from earlier apelike creatures. Recently a cave was discovered in Spain that contained more than 30 relatively complete skeletons of "archaic homo sapiens" (Homo heidelbergensis?) from about 300,000 years ago. The bodies had been dumped into a deep hole in the back of the cave, and so it seems that it was a sort of burial pit. The skulls were classic "archaic homo sapiens" in that they had extremely heavy brow ridges and so forth. Going further back, it's now beyond speculation that certain hominids like the famous three million year old "Lucy" (Australopithecus) walked on two legs, much like modern humans, but had brains only slightly larger than those of modern chimps. Going further ahead in time we have the famous "Homo erectus boy" (now classified as Homo ergaster) discovered by Richard Leakey's team in 1984. This 1.8 million year old specimen had a skeleton much like that of a modern human but the skull was quite intermediate in shape between modern humans and australopithecines, and a brain volume only 2/3 that of modern humans. Interestingly, this boy seems to have died at around age 10-14, and he died of acute vitamin-A poisoning, which can come only from eating the liver of a carnivore, which indicates scavenging. So it's pretty clear that human evolution has gone quite along the lines of other animal evolution, i.e., it's "bushy" and has many side branches.
How the Adam and Eve story -- if it's historical in any sense -- fits in, I have no idea. The poster aChristian has some ideas on this, and I have to admit that they're consistent with science and with a free interpretation of Genesis.
AlanF
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D wiltshire
Alan,
I basically agree with what science is bringing out about man's evolution, I see no reason not to.
How the Adam and Eve story -- if it's historical in any sense -- fits in, I have no idea. The poster aChristian has some ideas on this, and I have to admit that they're consistent with science and with a free interpretation of Genesis.
It is interesting that after Cain murdered his brother and was banished from his family's residence to become a wanderer, that he was afraid of people finding him and killing him Genesis 4:14.
This must clearly indicate that Adam was not the first man for Cain was Adams first born. If Adam was the first man, then at Cain's banishment who were these people that Cain was afraid of? They couldn't be Adam offspring.
I think we need to take into account the fact that all languages change and it is a very difficult to translate accurately such an ancient book. Hebrew at one time went into disuse which makes it even harder to translate. And any translation of Genesis is likely to have the preconcieved ideas of the translator influencing his rendition.