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Archiver > GENEALOGY-DNA > 2001-06 > 0991887153


From: Richard Gethmann <>
Subject: Re: [DNA] Darwin and DNA
Date: Thu, 07 Jun 2001 00:12:33 -0400
References: <cd.770b21e.284ecea2@aol.com> <200106062009270940.02C03E41@earthlink.net>


The best definition of species is that two organisms are considered to be members of different species if they can not produce viable and fertile hybrids. For example, the mule is the result of a cross between a horse and a donkey. But since mules are sterile, horses and donkeys are considered to be different species.

In the case of the moths in England, prior to the Industrial Revolution, dark colored moths landing on light tree trunks were easy to see, and thus, easily captured by bird predators. Light colored moths were harder to detect. The light colored moths had a greater likelihood of surviving and reproducing, thus the majority of the
moths would be light colored.

Following the Industrial Revolution, smoke residue and ashes covered the trees, so that now the dark colored moths were harder to find. Light colored moths were easier for the predators to find, thus now the dark colored moths had the best chance of reproduction. Therefore, the frequency of the colored moths increased.

Dick

Ralph Turner wrote:

> It is still survival of the fittest. There must be some genetic difference in the two varieties of moth. The definition of species is something else and cannot be tied to small differences in genes, such as darker and lighter skinned people. I think the definition of species has something to do with reproductive compatibility.
>
> *********** REPLY SEPARATOR ***********
>
> On 6/5/01 at 8:09 PM wrote:
>
> >May I point out that the light moth - dark moth observations are an example
> >of a change in gene frequency in a population.
> >
> >While this color change ~ may~ be natural selection it is ~not~ an example of
> >a new species.
> >
> >Although dark moths were rare in earlier times there were light and dark
> >moths of this species before the change in enviroment. There were still light
> >and dark moths after the smog made the trees dark. Dark moths became more
> >common in polluted areas but NO new DNA or genes were created. This is an
> >example of adaptation by genetic drift.
> >
> >This is not an example of the origin of a new species by random mutations.
> >
> >In a message dated 6/4/01 6:55:20 PM Eastern Daylight Time,
> > writes:
> >
> >
> >> Date:6/4/01 6:55:20 PM Eastern Daylight Time
> >> From: (Ralph Turner)
> >> Reply-to:
> >> To:
> >>
> >>
> >> This is a sucinct way of explaining how Darwin's theory works. He didn't
> >> know how it worked but now we do.
> >>
> >> RT
> >>
> >> *********** REPLY SEPARATOR ***********
> >>
> >> On 6/4/01 at 6:09 PM wrote:
> >>
> >> >In a message dated 6/3/01 9:07:45 PM Mountain Daylight Time,
> >> > writes:
> >> >
> >> >
> >> >>
> >> >> > Do the changes take place first in the physical shapes of faces ( body
> >> ),
> >> >> > skin color and hair texture first or does it occurs first in the dna?
> >> >> >
> >> >> In one of the earlier evolution studies that I recall, moths in Great
> >> >> Britain were studied and during the smoggiest times the dark ones did
> >> not
> >> >> get eaten. As the smog cleared up over the decades, the dark ones were
> >> seen
> >> >> and eaten and the ones with the whiter genetic makeup survived. Thusly,
> >> the
> >> >> DNA comes before the chicken.!!!
> >> >>
> >> >> Sorry, the last part of my reply got deleted. ??? Marilyn
> >> >>
> >>
> >>
> >
> >
> >
> >
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--
****************************************
RC Gethmann

****************************************
When you have eliminated the impossible,
whatever remains, however improbable,
must be the truth
A. Conan Doyle


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