What Is Evolution?

From: donna crumley (dhc195@soton.ac.uk)
Date: Mon Oct 06 1997 - 19:44:48 BST

Here's my summary of what I grasped and can remember from the
first seminar.

Steve posed the question: What is evolution? One way it was discribed
was: passing on 'recipies' for success. These 'recipies' are not passed
on in an abrupt obvious way, rather through a very subtle slow moving
process. It seems that the species which are most likely to survive are
those which pass on its strongest traits to the next generation. It is
for this reason that sexual reproduction (meiosis) is the most
successful way of creation. Sexual reproduction allows the strongest
survival traits of a creature (male and female) to be passed on to the
next generation. The other type of reproduction is mitosis, which
simply means the division of one cell into two, this results in the
"cloning' of the original organism. This 'exact copy' is not likely to
have the same ability to survive as the creature made as a result of
sexual reproduction has.

It is important the we produce bodies which are survivors because they
are vechiles for replicators (genes). In fact genes control embryonic
development, which means that they are partly responsible for their own
survival in the future. It is however, not possible to pinpoint genes,
they are usually something which is inferred.Genes have been doing the
same thing for millions of years, except that through evolution they
have become much more complex replicators (Think of the human eye for

We then went on to discuss the Environment of evolutionary adaptiveness
(EEA)( otherwise known as the 'original' environment ). The point was
made that most human changes in the last hundred million years have not
been as a result of evolutionary change. This can be illustrated by
examining proximal and distal changes in the environment. The argument
is that in the original environment distal changes brought about
changes in evolution (the child eating sugar for energy) and in today's
environment changes are bought about as a result of proximal
changes,(the child eating sugar because it tastes good). Changes are
brought on as a result of psychological, rather than survival needs.
This means that different species and individuals within a species all
adapt seperate ways of achieving their goal. Ultimately this means that
some creatures have stronger survival genes than others. This results
in competition, the survival of the fittest, I suppose. However, it has
been found that it is not only the fittest who are more likely to
survive, but also 'cheats'.

Cheats invade other creatures by pretending to have the same traits as
them and therefore surviving. Cheats are not found in an environment
where an evolutionary stable strategy (ESS) exists. Dawkins describes
an ESS as a strategy which, if most members of a population adopt it,
cannot be bettered by an alternative strategy. It means that the
environment is working as a unit to try and make things better for the
whole species. This ultimately means that it is impossible for the
species to be fooled by unwanted cheats. (I'm a bit confussed on this
topic, it seems to me that there is not much diffrence between an
environmentally stable strategy and straightforward altruism).
Especially as when reading one of Dawkin's examples, he describes the
digger wasp who basically puts her life at risk to provide shelter and
food for a succession of her larvae. Surely if this is a prime example
of a species acting in an evolutioanry stable strategy then it can be
associated with almost all species?!

I really am confussed, Steve please enlighten me. I've been reading The
Selfish Gene, which is helping, but i'm not sure if i've got the wrong
end of the stick.

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