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A Question About Evolution...

  1. Dec 5, 2018 #1
    Hi, i just read that a lot of genetic mutations are neutral and do not have much of an effect on the organism or the population.

    But sometimes, when the environment suddenly changes these neutral mutations can become advantageous and can aid the organism in surviving or in reproduction ect..

    I was just wondering if anybody could give me some examples of neutral mutations becoming advantageous after a sudden environmental change.. ?

    Thanks !
  2. jcsd
  3. Dec 5, 2018 #2


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    This doesn't actually fit what you're asking for, but it's a classic example of harmful mutation becoming beneficial.

    Look up malaria and sickle cell anemia.
  4. Dec 5, 2018 #3


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    Look for a study from the UK about a species of moth that spends most of its adult life clinging to particular trees. The moth populations before the Industrial revolution favoured light colored wings that matched the tree bark; apparently visually shielding the moths from predators. As coal burning became common, tree bark became colored with soot and grime making light colored moths more visible and dark winged moths more protected, less visible to predators and, therefor, favoured to reproduce.

    This study appears in several textbooks but I lack a reference to peer reviewed studies that validate the idea that "evolution" responds so quickly to this environmental change; i.e., persistent soot.

    [Edit: I wrote quotes around the word evolution to indicate I was using the word loosely to represent the functions responsible for biological change. Was not aware of sensitivity of this case study; only its ubiquity. Norm]
    Last edited: Dec 5, 2018
  5. Dec 5, 2018 #4
    Thanks guys, i will have a read about these topics !
  6. Dec 5, 2018 #5
    The species in question is the peppered moth (Biston betularia).
    An open-access critique of the debate over its importance as an example of evolution by natural selection is given here.
  7. Dec 5, 2018 #6


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    Caveat: I recall reading something about this turning out to be much less of a big deal than it first seemed. Something about the sampling not being very careful? Like: their number of populations were off because they were only recording ones they spotted - which sort of invalidated the whole study.

    Or something.

    I suspect I'm talkin' through my hat.

    There has been some controversy, although not of the kind in my example.
  8. Dec 6, 2018 #7


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    If Lepidoptera studies are too controversial an example, consider studies of zebra populations from modern Africa. Zebra coats, not unlike our moths, display complex patterns of light and dark. Previous theories of the selective evolution of the distinctive zebra pattern involved comparisons to natural grasses with a nod toward herd behaviour in the presence of predators. A recent Nova science program claimed data supports hypotheses that zebra stripes create a moire pattern in the predator's vision interfering with the predator striking vulnerable zebra anatomy. Herd "crossing pattern" movements in the presence of predators also make sense if the object is to "confuse the cat".

    Coincidentally, both examples -- moths and zebras -- involve melanism, predator-prey interactions, light/dark patterns and cryptology (in this context of camouflage). In this case the environmental changes could be changes from forest to grasslands, predator-prey distributions, climate, and binocular vision enhancements in large predator species; along with divergence of zebra coat patterns from donkeys and other related species.

    Last edited: Dec 6, 2018
  9. Dec 6, 2018 #8


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    I'm not quite sure this is what you are looking for but....

    It looks like humans picked up a gene mutation from Denisovans that later became useful when they migrated to higher altitudes in Tibet...

  10. Dec 22, 2018 #9
    A good example would be in people who are naturally resistant to HIV, they lack a particular receptor on their cells because of a mutation, its not particularly common and generally this has no real effects on the person, that is until HIV came along.
  11. Dec 26, 2018 #10


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    So, no moths, zebra data suspect IMO. Some of the expected patterns could be artifacts of photography and processing. Filminig hunts also adds interference to the data.

    Third data sources: recordings of bird calls including photography accessible online at several universities. Here's data on a Western finch from Cornell.

    Depending on the scope of your research, one could select and track species and locations across the globe. Finch species are well distributed. Search early source recordings of common species. Can you spot adaptations in finch behaviour based on qualities measured in the calls? Can sound data measure variables about the specimen's health? What other data can be correlated?
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