Bio1151
Chapter 23
The Evolution of Populations
A
is a
localized
group of individuals of a species.
Natural selection acts on individuals, but
evolve
, based on
variations
that are inherited over generations.
As a population evolves, its heritable variation is reflected in change of
and
frequencies
.
A non-evolving population reaches the
equilibrium
due to Mendelian
of alleles.
At Hardy-Weinberg equilibrium, the distribution of 2
p
and
q
in a population can be modeled by two
equations
.
Natural populations may
if conditions deviate from the Hardy-Weinberg model.
Genetic
in small populations tends to
genetic variation. In very small populations the
effect
can contribute to severe loss of genetic diversity.
Gene
from the movement of individuals or gametes between populations can affect allele frequencies and tends to
genetic differences between
populations
.
is the basis for
natural
selection, and results in unequal reproduction of alleles.
Sexually reproductive organisms often exhibit
mating behaviors such as
selection
and
selection
.
Natural
selection
is the major mechanism that drives adaptive
.
Causes of Evolutionary Change: