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Thread: Instant Evolution (& the Fossil Record)

  1. #1 Instant Evolution (& the Fossil Record) 
    Forum Radioactive Isotope zinjanthropos's Avatar
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    Recently caught a PBS broadcast of "Nature" the other nite. It was about dogs and how they evolved. I won't bore you with details but suffice to say that the consensus is that wild dogs evolved to become man's best friend as well as branching out as different breeds in a very short time. This started me wondering if evolution may be one or a series of steps that themselves are very short in geological terms. I went to Google, something I hate doing, and found this article right off the bat.

    http://news.nationalgeographic.com/n...evolution.html

    Considering the claim that there is a lot of missing transitional fossils, could it be possible that abrupt changes occur more frequently than than changes that span long time periods? Wouldn't the odds of finding transitionary fossils of animals that evolved quickly be practically zero?


    All that belongs to human understanding, in this deep ignorance and obscurity, is to be skeptical, or at least cautious; and not to admit of any hypothesis, whatsoever; much less, of any which is supported by no appearance of probability...Hume
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    Forum Cosmic Wizard paralith's Avatar
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    I know I've written this somewhere before, but I'll say it again: the fossil record is spotty of transitional forms for good reason. The likelihood that any single animal will become fossilized is extremely, extremely low.

    For fossils to form, first the animal must have bony or other similar parts that can be fossilized. When it dies the bones need to not be shattered or destroyed completely by predators. The bones need to be covered in sediment etc relatively quickly before they erode away. As they slowly fossilize in the earth, the shifting of the sediment layers could once again break apart and grind down the bones. Given all this, if they are still intact, they then need to be close enough to the surface to either rise by themselves to be found by people, or shallow enough so that we can dig down and find them.

    The fossil record is an incomplete sample of life that has existed on earth. It is to be expected that a lot of transitional fossils, especially of species that may have existed for a relatively short time or lived in areas with bad conditions for fossilization, may never be found by humans.


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    Forum Radioactive Isotope zinjanthropos's Avatar
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    Quote Originally Posted by paralith
    I know I've written this somewhere before, but I'll say it again: the fossil record is spotty of transitional forms for good reason. The likelihood that any single animal will become fossilized is extremely, extremely low.
    The fossil record is an incomplete sample of life that has existed on earth. It is to be expected that a lot of transitional fossils, especially of species that may have existed for a relatively short time or lived in areas with bad conditions for fossilization, may never be found by humans.
    I realize that and I would never contest it. If rapid evolution occurs then it would also add to the low probabilty of ever finding transitionary fossil evidence.

    Not sure if that link I gave is actually accessible but its a story about large ground finches that arrived on the Galapagos Islands in 1982. Since then medium ground finches living there have developed a smaller beak in order to survive, a result that's directly due to the competition for food with the large ground finch. 25 years apparently is enough time for this change to be noticeable.
    All that belongs to human understanding, in this deep ignorance and obscurity, is to be skeptical, or at least cautious; and not to admit of any hypothesis, whatsoever; much less, of any which is supported by no appearance of probability...Hume
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    Forum Isotope Bunbury's Avatar
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    Your link doesn't work because it has an extra t in http. However, your topic reminded me of this, about foxes, which are not pack animals like wolves, being domesticated in around 45 years:

    http://findarticles.com/p/articles/m...08/ai_n9501670
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    WYSIWYG Moderator marnixR's Avatar
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    it's just that human (even if unintentional) selection is far more directed than natural selection

    evolution on time scales of a few years may go at a fair speed, but chances that environmental conditions change in the next few years and evolution goes in reverse - it's what seen in the fossil record as stabilising selection
    "Reality is that which, when you stop believing in it, doesn't go away." (Philip K. Dick)
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    Administrator KALSTER's Avatar
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    Some interesting points where made here, http://www.thescienceforum.com/Evolu...urts-8442t.php. I can't see any problem with the missing transitional species. There seem to be adequate explanations for it.
    Disclaimer: I do not declare myself to be an expert on ANY subject. If I state something as fact that is obviously wrong, please don't hesitate to correct me. I welcome such corrections in an attempt to be as truthful and accurate as possible.

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    dogs are bred, and not naturally evolved.
    this inbreeding tends to cause faults in some of the species,
    like bulldogs generally poor hearts, and tibetanian spaniels trouble with breathing, due to its short snout.
    when you have eliminated the impossible, whatever remains, however improbable, must be the truth
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  9. #8  
    Forum Radioactive Isotope zinjanthropos's Avatar
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    Quote Originally Posted by Bunbury
    Your link doesn't work because it has an extra t in http. However, your topic reminded me of this, about foxes, which are not pack animals like wolves, being domesticated in around 45 years:

    http://findarticles.com/p/articles/m...08/ai_n9501670
    Fixed it....thanks.
    All that belongs to human understanding, in this deep ignorance and obscurity, is to be skeptical, or at least cautious; and not to admit of any hypothesis, whatsoever; much less, of any which is supported by no appearance of probability...Hume
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  10. #9  
    Forum Professor sunshinewarrior's Avatar
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    To add to what paralith, and others, have said, it is this relative speed of change in lineage that gave rise to Gould's notion of punctuated equilibrium. Whilst I suspect he reified it, to the detriment of his main point, it is a solidly respectable notion in modern biology that most change (from one species to another, morphologically speaking) happens very swiftly compared to the lifespan of a successful species.
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  11. #10  
    Forum Radioactive Isotope zinjanthropos's Avatar
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    I was just thinking about how much we rely on evidence. I don't think it is too much out of the realm of possibilities that a 'lack of evidence' is evidence itself.

    Why is it generally assumed that evolution takes a great many years and generations? Fruit flies?
    All that belongs to human understanding, in this deep ignorance and obscurity, is to be skeptical, or at least cautious; and not to admit of any hypothesis, whatsoever; much less, of any which is supported by no appearance of probability...Hume
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  12. #11  
    Forum Cosmic Wizard paralith's Avatar
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    Quote Originally Posted by zinjanthropos
    I was just thinking about how much we rely on evidence. I don't think it is too much out of the realm of possibilities that a 'lack of evidence' is evidence itself.

    Why is it generally assumed that evolution takes a great many years and generations? Fruit flies?
    It's not. Evolution is simply a change in the gene frequencies of a population, and for most species, that happens all the time on a small scale. Micro evolution occurs on a much smaller time scale than macro evolution - which is why a lot creationists and IDers will accept micro evolution but not macro evolution. Macro evolution is the accumulation of all those micro evolutions over long periods of time, leading to much more radical overall changes. It can of course happen somewhat quicker, say with just the right mutation in just the right place, or with several successive generations of very stringent natural selection. But for the most part, larger changes take more time to accumulate.
    Man can will nothing unless he has first understood that he must count on no one but himself; that he is alone, abandoned on earth in the midst of his infinite responsibilities, without help, with no other aim than the one he sets himself, with no other destiny than the one he forges for himself on this earth.
    ~Jean-Paul Sartre
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