Subject:
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Re: evolution (was Re: Mormon bashing again)
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Newsgroups:
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lugnet.off-topic.debate
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Date:
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Mon, 6 Mar 2000 18:51:41 GMT
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Viewed:
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958 times
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Shiri Dori wrote:
> Right. But that's not the whole story.
>
> IIRC, the moth population had 5% dark moths, who were eaten quickly because of
> the white beech tree (ie, they had no camouflage). The black color, was, I
> think, a mutation (or perhaps a recessive gene? I don't remember).
<snipped a bunch>
Shiri's description is very good, I'll elaborate on a few points.
The moth in question is the Peppered Moth(_Biston betularia_). Before the
industrial revolution, the predominant form seen in the woods of England
was
white with dark brown spots, altought the population ranged from very light
moths to very dark moths. I think(1) the cause of the variation was a case
of simple
dominance/recessive interaction, dark=homozygous dominant/hetreozygous
while
light is recessive. therefore the breeding white moths with white moths
could not
produce darks, but breeding dark with dark would produce 3/4s dark 1/4
white.
There was a lot of selective pressure on the population to favor lightered
colored
moths because they were the most readily camaflouged on the light colored
birch
trees. As the trees were covered with black soot from the burning of coal,
the
light moths stood out and were eaten, while the dark ones were now hidden
better.
The change from a light to a dark color took many years, it wasn't an
overnight
thing. Like other's have said the population change back to light colored
when
the environment was cleaned up.
This is an example of evolution(2) through natural selection. There are
other types
of evolution.
-chris
1- i sorta disagree with this, although i can't put it into words right
now.
however, i should point out the mutation plays(for the purposes of this
discussion) almost no role in the color change. The mutation rate for
the
color genes of Biston betularia are way too low to account to for the
speed
of the change(8% would be needed, actual rate is 0.005 percent).
2- microevolution actually much different than macro
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Message has 1 Reply:
Message is in Reply To:
 | | Re: evolution (was Re: Mormon bashing again)
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| (...) Right. But that's not the whole story. IIRC, the moth population had 5% dark moths, who were eaten quickly because of the white beech tree (ie, they had no camouflage). The black color, was, I think, a mutation (or perhaps a recessive gene? I (...) (25 years ago, 6-Mar-00, to lugnet.off-topic.debate)
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