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Thread: Evolution

  1. #1 Evolution 
    Forum Freshman doomsday2012's Avatar
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    How does evolution take place? Are the mutations that occur random?


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  3. #2  
    WYSIWYG Moderator marnixR's Avatar
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    modification of DNA though mutation is random relative to the survival value for the organism where it happens
    whether it is random in other senses may be debatable


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  4. #3  
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    I wouldn't call sexual selection random at all...
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  5. #4 Re: Evolution 
    Forum Cosmic Wizard spuriousmonkey's Avatar
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    Quote Originally Posted by doomsday2012
    How does evolution take place?
    It takes place by descent with modification over time.

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  6. #5  
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    What about the horizontal transmission of genes, is that more structured?
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  7. #6  
    WYSIWYG Moderator marnixR's Avatar
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    Quote Originally Posted by gottspieler
    I wouldn't call sexual selection random at all...
    i was only answering the 2nd question, which concerned itself with mutation
    i'm very well aware that the direction of evolution is far from random since it's guided by the scythes of natural and sexual selection
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    Forum Cosmic Wizard i_feel_tiredsleepy's Avatar
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    Quote Originally Posted by Prometheus
    What about the horizontal transmission of genes, is that more structured?
    HGT complicates issues of mapping lineages, but it doesn't complicate evolution. Genes propagated by HGT rather than sexual or asexual reproduction are still subject to natural selection.
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  9. #8  
    Forum Masters Degree Golkarian's Avatar
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    The mutations are generally assumed to be random, though this may just be a convenient assumption. Some processes in evolutioin (like mutation or genetic drift) are random but not all. Selection (natural, sexual, artificial) work by increasing the number of organisms with a certain trait, this is considered evolution. But more interesting is when you combine more than one form of evolution, like combining mutation and selection. Say a trait gives an organism an advantage over the rest (selection), the organism's descendants (and hence also the trait) will become more numerous. This incrases the chances of a mutation building on that trait, if the new mutation is advantageous the process will repeat itself, allowing for a system formed from several mutations. Note that this doesn't work for disadvantageous mutations or systems, since the chances (without selection) of the system forming are very small.
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