Environmental Engineering Reference
In-Depth Information
have any bearing on fitness. Potential mates might find certain physical attrib-
utes attractive in the first place and perhaps be inclined to pair with healthy
looking individuals more so than sickly looking individuals. But, physical
health is only a proximate indicator of potential fitness. Fitness in a Darwin-
ian evolutionary sense represents the lifetime contribution of an individual or
a strategy to the breeding population, relative to other individuals or strate-
gies. It is a measure of the relative success of a strategy in the game.
Individuals or strategies with low
fitness (be it through lower offspring
production or early death) fulfill the
object of the game less well than in-
dividuals with higher fitness. Conse-
quently, there will be fewer copies of
themselves represented in future iter-
ations of the game.That is, their strat-
egy type or set of traits will become
increasingly more rare or may even
be absent in future populations.
Essentially, what is being described
here is a process that leads to change in the mean value of a trait or strat-
egy in a population. It began with an ensemble of individuals that, on the
average, have the capacity to make adjustments to environmental change
modestly fast.As the environment changes, those individuals with difficulty
coping become stressed and produce fewer genetic copies of themselves than
individuals that cope well with the environment.The result is that the envi-
ronmental change will favor certain coping strategies over others.The envi-
ronmental gauntlet known as Nature determines whether or not a strategy
stays in the game through a process of differential survival and reproduc-
tion.The process is known as natural selection. It is a process that begins
with biological differences in some trait(s) among individuals and may lead
to a change in the mean value of that trait in a population.The key point
here is that
biological differences among individuals
exist.Without these differ-
ences natural selection could not happen and species populations will be
unable to adapt to new environmental conditions.
Fitness in a Darwinian evolutionary
sense represents the lifetime con-
tribution of an individual or a strat-
egy to the breeding population,
relative to other individuals or
strategies. It is a measure of the
relative success of a strategy in
the game.
Evolution by Natural Selection
Although natural selection sorts among biological differences in a popula-
tion, such a process does not de facto mean that we should see a lasting
