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    i dont really understand the 3 types of natural selection
    -stabilising selection
    -directional selection
    -disruptive selection

    in my notes its talking about extremes of phenotype and stuff. but can anyone simplify this? lol
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    The clue is in the name

    Stabilising is where extremes always die out. So say... a really big mammal can't survive because it can't get enough to feed itself; but the runt of the litter starves. So mammals of the "right" size always survive.

    Directional is pushing in one direction. So say... a darker moth is better camouflaged, so the darkest moths survive until the whole species becomes as dark as possible? Or say faster cheetahs always get to eat more. So cheetahs get faster and faster as the species evolves

    Disruptive selection is comparatively rare. It's where the extremes survive, but "average" just doesn't cut it. Like Darwin's finches. In the dry season the ones with small beaks can eat tiny grains, and the ones with big beaks can crack open hard nuts, but medium sized beaked birds end up starving.
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    (Original post by Bekaboo)
    The clue is in the name

    Stabilising is where extremes always die out. So say... a really big mammal can't survive because it can't get enough to feed itself; but the runt of the litter starves. So mammals of the "right" size always survive.

    Directional is pushing in one direction. So say... a darker moth is better camouflaged, so the darkest moths survive until the whole species becomes as dark as possible? Or say faster cheetahs always get to eat more. So cheetahs get faster and faster as the species evolves

    Disruptive selection is comparatively rare. It's where the extremes survive, but "average" just doesn't cut it. Like Darwin's finches. In the dry season the ones with small beaks can eat tiny grains, and the ones with big beaks can crack open hard nuts, but medium sized beaked birds end up starving.

    thanks! that was really helpful =)
 
 
 
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