How evolution works

Sydney Shall bafa1 at central.susx.ac.uk
Wed Jun 8 07:27:30 EST 1994


Cathy Woodgold (woodgold at seismo.emr.ca) wrote:
: In article dio at nwfocus.wa.com, venezia at zgi.com (Domenick Venezia) writes:
: > Cathy Woodgold (woodgold at seismo.emr.ca) wrote:

: > ..
: > : helps a lot too.)  Anyway, this is one way that bad mutations are weeded out
: > : in the human species;  that method can't be used by an individual who is
: > : living thousands of years!

: > Correct me if I misunderstood, but what you are saying is that I should
: > consent to die for the betterment of human evolution? 

: I'm correcting you.  I'm saying nothing of the sort.  I don't remember using
: the word "should" nor any similar word;  this is a scientific, not an ethical
: discussion, isn't it?  I'm trying to understand how human evolution works.
: My reason for doing so is the opposite of what you seem to think I mean.
: Actually, I think people (most of the time) "should" try to live as long
: and as healthily as possible.  I don't see how this could affect human evolution
: in a bad way ... especially when one is talking about someone who has already
: had all the children they're likely to.  Having children at an older age
: may affect their genes a bit, but that's a separate sociocultural issue and
: is certainly not going to have a major impact on the gene pool.  (The better
: environment, financially, socially and so on, that an older parent tends to
: be able to provide, is probably much more important than the gene quality.
: For example, most teenage mothers do not breastfeed their children here
: in Ottawa.)  I think people "should" have children at whatever age they decide
: is best for their family (or whatever age they choose to) and "should" usually
: try to live as long as possible and try to help their children be healthy and
: live as long as possible.  I'm intrigued by the possibility that something about
: telomeres may be useful in helping people live longer, and I'm exploring various
: sides of the idea, with the hope that I and others may be able to live longer.
: If I think of something like "Oh, well, it might not work because...." I will
: say that, too .... not because we shouldn't try to live longer but because that's
: part of the process of figuring out how to live longer!  By the way, I said
: miscarriages happen;  I didn't say we should try to make more of them happen!
: I gave information about how to cut down the number (excellent nutrition by
: both parents starting about three months before conception;  Dad can go back to
: junk food after conception) in the hope that some people would use it.  I want
: to help other people to be healthier.

: Sorry if this sounds like a tirade.  :)

: Cathy        TISSATAAFL         my personal opinions only




I would like to add another thought to the discussion of human evolution
and longevity.  Presumably if there are genes which modulate longevity,
for which there is good experimental evidence, then these genes first
appeared and were later modified by mutation and natural selection.  It
would therefore be useful to find these genes and determine would
influence they have on the development of animals.

All attempts to lengthen life-span in humans "should" in my view be
coupled to improving the health and welfare of all, as well as older
people.

The "novel" idea that I would advance is that there is no natural
selection in human populations since about the beginning of the 20th
Century, because in general people are over-riding their biological
ability to have many offspring by "social" decisions to limit the number
of children.  In most parts of the world the number of children achieved
is almost entirely a "social" not a "biological" decision.  

This idea does not exclude the idea that our current biology as humans
includes selection over the last million years during which time we have
survivied as social Homo sapiens.

-- 
Sydney SHALL,
Laboratory of Cell and Molecular Biology,
Biology Building, University of Sussex,
Brighton, East Sussex BN1 9QG,




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