Search All of the Math Forum:

Views expressed in these public forums are not endorsed by NCTM or The Math Forum.

Notice: We are no longer accepting new posts, but the forums will continue to be readable.

Topic: Several questions on evolution, and mutation (rate)
Replies: 52   Last Post: Sep 8, 1996 9:44 PM

 Messages: [ Previous | Next ]
 James Foster Posts: 11 Registered: 12/8/04
Re: Several questions on evolution, and mutation (rate)
Posted: Sep 4, 1996 8:11 PM

Ram Samudrala (ram@mbisgi.umd.edu) wrote:
: James Foster (foster@cs.uidaho.edu) wrote:

: >Evolution is the tendency of a distribution of traits to drift over
: >time. That is, evolution is change in organisms across generations.
: >Natural selection is the mechanism which drives this drift.

: This is an issue that has always perplexed me. I look at evolution as
: simply as change (like in the formation of new function). I don't see
: how natural selection can drive change. I realise that's not exactly
: what you're saying, but what would you call the evolution of a new
: function in a particular orgasm (due to a mutation, say)? I don't see
: why you say "across generations" in your definition of evolution.

Well, "evolution" does mean "change". But to biologists it really means
"a change in the distribution of characters ocross generations".
Selection CAN drive THIS, of course. Selection cannot operate at all on
a single individual divorced from any consideration of it's progeny.

I'd say the thing you describe is just good old fashioned change in an
individual...aka mutation.

: To clarify, suppose there was a single bacterium that was susceptible
: to an antibiotic. That baterium underwent a mutation in one of its
: genes, and consequently one of its proteins, and that one protein
: bound to the antibiotic and rendered it ineffective. I would call
: this "evolution" (of a new function, i.e., antibiotic resistance).
: The fact that the bacterium could survive in an environment with this
: antibiotic due to this evolution, and thus reproduce, passing this
: gene on to its "offspring" across generations, while other bacteria
: that didn't have this gene died, is what I'd call natural selection
: (of that antibiotic resistance function).

Without passing it on, that's just "mutation"...ie., "change".

: >We have observed both natural selection AND evolution: in the lab AND
: >in nature.

: Do you know of any references where evolution (i.e., arising of new
: function) has been observed in the lab or in nature?

Of course...otherwise I wouldn't have mentioned it! Probably the best
written is "The Beak of the Finch" by Weiner. Won the Pulitzer.
Lovely.

There are many others of course. "The Coming Plague" talks about a
particularly frightening case of observed new funcationality. Or you
could speak to anyone who develops new strains of crops or cattle.

It happens all the time.
--
James A. Foster email: foster@cs.uidaho.edu
Laboratory for Applied Logic Dept. of Computer Science
University of Idaho www: http://www.cs.uidaho.edu/~foster

-----BEGIN PGP PUBLIC KEY BLOCK-----
Version: 2.6.2
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=G/K7
-----END PGP PUBLIC KEY BLOCK-----

Date Subject Author
8/15/96 Andrew Singer
8/16/96 Lluis Ribas
8/16/96 Doug Yanega
8/17/96 Leonard Evens
8/16/96 KIRKX L AUGUSTIN
8/17/96 Leonard Evens
8/28/96 Brian Williams
8/29/96 Lauren Owens
8/18/96 Felix J. Thibault
8/20/96 Vincent R. Johns
8/23/96 Richard M Kliman
8/25/96 David Beorn
8/26/96 Vincent R. Johns
8/27/96 Steve McGrew
8/27/96 James Foster
8/29/96 David Beorn
8/30/96 James Foster
8/31/96 L.A. Moran
9/3/96 James Foster
9/4/96 L.A. Moran
9/4/96 James Foster
9/4/96 Ram Samudrala
9/4/96 James Foster
9/4/96 Ram Samudrala
9/5/96 James Foster
9/5/96 Ram Samudrala
9/6/96 James Foster
8/27/96 Joan Shields
8/28/96 Steve McGrew
8/29/96 David Beorn
8/30/96 Jerry Learn
8/31/96 Doug Easton
8/30/96 Larry Edwards
8/30/96 Doug Yanega
9/7/96 David Beorn
8/27/96 David Dixon
8/28/96 Dana Gourley
8/30/96 Herman Helmuth
9/6/96 Jerry Clark
8/22/96 Truett L Smith
8/28/96 Brian Williams
8/23/96 Karl
8/24/96 Steve McGrew
8/25/96 Arthur Chandler
8/21/96 vorsterd@iafrica.com
8/22/96 Anthony Campbell
8/22/96 Mary K. Kuhner
8/31/96 Arthur Chandler
9/4/96 David Wilson
9/6/96 Ram Samudrala
9/8/96 David Wilson