Download Concept 14.4: Microevolution is a change in a population`s gene pool.

Concept 14.4: Microevolution is a
change in a population’s gene pool.
Examples of Microevolution
House sparrows adapting to climate in North America
Insects evolving resistance to pesticides
Gene Pool
All of the alleles in all of the individuals
that make up a population.
z The gene pool is where genetic variation
is stored.
z Genetic variation is the “raw material” of
evolution.
z
2 processes that can lead to an
increase in genetic variation.
1. Mutation: a change in an organism’s
DNA
–
If this mutation is carried by a gamete, the
mutation enters the population’s gene pool.
2 processes that can lead to an
increase in genetic variation.
2. Genetic Recombination: the result of
the processes of meiosis and fertilization
–
Alleles in the gene pool are “shuffled” and
“dealt” to the offspring.
3 processes that can lead to a
change in the gene pool.
1. Genetic Drift: change in the gene pool
due to chance events
–
The smaller a population, the more impact genetic
drift can have.
3 processes that can lead to a
change in the gene pool.
2. Gene flow: change in the gene pool due
to the exchange of genes with another
population
3 processes that can lead to a
change in the gene pool.
3. Natural Selection: change in the gene
pool due to differences in survival and
reproductive success among members of
the varying population
Biological Fitness
z
The contribution that an individual makes
to the gene pool by producing offspring.