Peter,
Until fairly recently I think man really did very limited selection of stock or plants he raised. Take plant seeds. Many plants shed seeds about as fast as the seeds mature and they do not always mature at the same time. Lots of grasses do this. The mature seeds are held very weakly. What man did was simply harvest. Any plants that held their seeds better ended up in the harvest and were replanted and in only a few generations the result was grasses (Wheat, oats,...) that held their seeds.
Or take the second oldest domestic, pigeons. Man simply gave them a place to nest. They foraged for their own food. Those that were more human tolerant stayed around. The guy that was in charge of butching and plucking likely left the largest young to breed and ate the smaller less desirable ones. In a few generations the human tolerance and size went up automatically without the "breeder" actually picking mates.
Dick
" Any discovery made by the human mind can be explained in its essentials to the curious learner." Professor Benjamin Schumacher talking about teaching quantum mechanics to non scientists. "For every complex problem there is a solution which is simple, neat and wrong." H. L. Mencken
--------------------------------------------
On Tue, 9/6/16, Peter Loring Borst <[log in to unmask]> wrote:
Subject: Re: [BEE-L] evolutionary pressures
To: [log in to unmask]
Date: Tuesday, September 6, 2016, 7:43 AM
> But, in either case such
selection is still evolution. Evolution is change in
response to a stimulus. Nature can be the stimulus,
but so can man.
OK, I see what you mean by that. Evolution includes
artificial selection. Then, the distinction is between
natural and artificial selection, and also the product.
Natural selection produced what we call "nature," the nature
that we wish to preserve, being as it is the product of 4
billion years. Mankind's hands are all over the planet now,
so the distinction between nature and man-created may be
subtle and vanishing.
* * *
We perceive today, as did Darwin, that natural selection is
the environmentally
driven mechanistic process by which more advantageous
traits are, on the whole, passed on to succeeding
generations more often
than less advantageous traits because of differential
reproduction of the
individuals possessing them. Sexual selection is a natural
process of intraspecific
competition for mating rights.
Artificial selection, generally the motive force behind
domestication,
is often equated with selective breeding.
This often amounts to prezygotic selection (where mates are
chosen
by humans) versus postzygotic selection (where the most fit
progeny
reproduce differentially) as in natural selection. Although
natural selection
plays a considerable role in the evolution of many traits
(e.g., disease
resistance) during the animal domestication process, sexual
selection is
effectively trumped by the human-imposed arrangements of
matings
and often by the human desire for particular secondary
sexual characters.
Artificial selection is a conscious, if unintentional,
process, and therefore
is generally considered to be effected only by humans.
Driscoll, C. A., Macdonald, D. W., & O'Brien, S. J.
(2009). From wild animals to domestic pets, an evolutionary
view of domestication. Proceedings of the National Academy
of Sciences, 106(Supplement 1), 9971-9978.
***********************************************
The BEE-L mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software. For more
information, go to:
http://www.lsoft.com/LISTSERV-powered.html
***********************************************
The BEE-L mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software. For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html
|
