Perhaps there is a different way you can say what you mean?

It is always important to remember that mutations are not
directional. What is turned on and off might at times be
(epigenetics) in that those responses can happen in relation to some
environmental factors (which may be why a number of plants accumulated
many more genes than we have) but mutation itself is not
directional. It's a crap shoot. The genetic status of a population
lags behind the stresses that caused die offs or less drastically
reduced the viability of certain characteristics.
As the Red Queen said "You have to keep running as fast as you can to
stay in the same place." In E&E (Evolution and Ecology) studies that
is actually referred to as the "Red Queen Hypothesis.

For anyone who may want:
Basic Mendelian (not the only mode but what most people are familar
with):
http://anthro.palomar.edu/mendel/mendel_1.htm

Doing basic diploid squares (not all life forms are diploid, ex.
banana trees):
http://anthro.palomar.edu/mendel/mendel_2.htm

Some exceptions to simple inheritance patterns:
http://anthro.palomar.edu/mendel/mendel_3.htm

http://www.slh.wisc.edu/genetics/basics.dot
with
http://www.slh.wisc.edu/genetics/basics_disease.dot
very relevant to the original discussion

Shoot, am I seeing things or is it not giving the direct links? Oh,
well. If so, you can navigate in there.

Of course, it is more complicated than that; otherwise, genetics would
not be a major biological discipline with subsets such as molecular
genetics, classical genetics, population genetics, evolution,
paleontology, some aspects of ecology, and medical genetics.