Download Review for Final: Chap 16: Evolulution of Populations

Review for Final: Chap 16: Evolulution of Populations
1. What is a gene pool?
The collective or combined genetic
information of all members
of a particular population
2. What is the relative frequency of an allele?
The number of times the allele
occurs in a gene pool compared
with the number of times other
alleles occur.
3. What are the 2 main sources of genetic
variations?
1-mutations 2-gene shuffling
(sexual reproduction)
4. What determines the phenotype of an
oganism?
The number of genes that control
the trait.
5. What is the difference between polygenic
and single-gene traits?
Polygenic traits are controlled by
multiple genes; Single gene traits
controlled by 2 alleles.
6. How does natural selection affect
single-gene traits?
7. How does natural selection affect
polygenic traits?
8. Draw a curve diagram to show each
of the 3 ways that natural selection affects
phenotypes.
Can lead to changes in allele
frequencies, and evolution
Will affect the distribution of
phenotypes in any of 3 ways;
directional selection, disruptive
selection, stabilizing selection
9. Is natural selection the only source of
evolutionary change?
No, genetic drift: a series of
random occurences in a small
population may change the relative
frequency of an allele by chance
10. Are there any conditions under which
evolution will not occur?
Yes: the Hardy-Weinberg principle
11. What is the Hardy-Weinberg principle?
Allele frequency will remain
constant in a population unless one
or more factors cause the population
to change.
12. What conditions need to be met for
Evolution NOT to occur?
1. Random mating.
2. population is large
3. no movement in or out of population
4. no mutations
5. no natural selection
13. For evolution to progress to the
point where a new species forms,
what condition is necessary?
Populations must be reproductively
isolated
14. How can a population become
reproductively isolated?
1. Behavioral isolation: differences in
courtship rituals, for example
2. Geographic isolation: rivers,
mountains, etc.
3. Temporal isolation: reproduction at
different times
15. Describe the 6 steps in the speciation
of Darwin’s Finches
1. Founders arrive (a small population
has broken away)
2. Separation of populations: on
different islands
3. populations on each island became
adapted over time
4. Reproductive isolation
5. Ecological competition: birds with
most adaptations (differences) have
highest fitness
6. continued evolution