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Author Topic:   How is Natural selection a mechanism?
Wounded King
Member (Idle past 2839 days)
Posts: 4149
From: Edinburgh, Scotland
Joined: 04-09-2003


Message 15 of 191 (525443)
09-23-2009 11:57 AM
Reply to: Message 14 by Perdition
09-23-2009 11:51 AM


Re: Mutating genes
In species that are not monogamous, this mutational spread (or genetic drift) increases

In population genetics 'genetic drift' is something quite specific, I think the way you are using it here is confusing especially when you go on to essentially conflate selection with 'genetic drift'.

TTFN,

WK


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 Message 14 by Perdition, posted 09-23-2009 11:51 AM Perdition has responded

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Wounded King
Member (Idle past 2839 days)
Posts: 4149
From: Edinburgh, Scotland
Joined: 04-09-2003


Message 17 of 191 (525482)
09-23-2009 2:37 PM
Reply to: Message 16 by Perdition
09-23-2009 2:01 PM


Drift
'Genetic drift' refers to the changes in allele frequency between one generation and the next in a population which can be attributed to random factors. What you describe, natural random variation in mating success, could be one such factor. Being hit by a tree falling over clearly does curtail an organisms chances of reproductive success.

Your monogamy issue is pretty abstruse though, and certainly not considered a particularly important element of genetic drift as far as I know.

TTFN,

WK


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Wounded King
Member (Idle past 2839 days)
Posts: 4149
From: Edinburgh, Scotland
Joined: 04-09-2003


Message 34 of 191 (525644)
09-24-2009 5:00 AM
Reply to: Message 32 by Coyote
09-23-2009 6:53 PM


Re: Mutating genes
Coyote writes:

Kevin123 writes:

What slowed evolution down?

Perhaps successful adaptation to niches and slower changes in environment.

The obvious answer to my mind is that generation times vary greatly. A small mammal like the mouse has a generation time of 10 weeks from being born to being able to give birth. In primates it is much longer, for chimps and human it is around 15-20 years. I can certainly see how that could slow evolution down, by a factor of about 78, and the difference compared to a very primitive multicellular life form should be larger again. Brine shrimp for example have a generation time of 3 weeks giving a factor of 260.

This makes sense to me at least.

TTFN,

WK


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