Please explain natural selection...
stephen at access.digex.net
Wed Jun 9 09:45:16 EST 1993
I am reading _Blueprints_ by Maitland Edy and Donald Johanson (_Lucy_) and
I don't think I quite understand the concept of natural selection.
I understand that when a mutation in an animal forms that mutation can be
carried by many generations but not be readily apparant thus explaining
why blending does not occur. And I understand that when a trait forms
that is in some way advantageous to an animal it may become dominate within a
However one could conclude from this that if I bred only large mice that
over time my mice would become larger and larger - but eventually the mice
will only get so large before they become sick, or sterile or still born -
there is a certain mice'ness that can not be selectivly bred out.
So how does nature form entirely new animals? I understand natural
selection to the point that it favors certain traits under certain
environmental conditions, but it does not seem to explain how entirely new
species are formed?
More information about the Mol-evol