Download Ch. 16 Evolution of Populations Name Period ______ 16

Ch. 16 Evolution of Populations
Name _______________________
Period ___________
California State Standards covered by this chapter:
Evolution
7. The frequency of an allele in a gene pool of a population depends on many factors and may be stable or unstable
over time. As a basis for understanding this concept:
a. Students know why natural selection acts on the phenotype rather than the genotype of an organism.
b. Students know why alleles that are lethal in a homozygous individual may be carried in a heterozygote and
thus maintained in a gene pool.
c. Students know new mutations are constantly being generated in a gene pool.
d. Students know variation within a species increases the likelihood that at least some members of a species will
survive under changed environmental conditions.
8.
Evolution is the result of genetic changes that occur in constantly changing environments. As a basis for
understanding this concept:
a. Students know how natural selection determines the differential survival of groups of organisms.
b. Students know a great diversity of species increases the chance that at least some organisms survive major
changes in the environment.
c. Students know the effects of genetic drift on the diversity of organisms in a population.
d. Students know reproductive or geographic isolation affects speciation.
e. Students know how to analyze fossil evidence with regard to biological diversity, episodic speciation, and
mass extinction.
Read the appropriate section in the textbook and lecture notes before answering the following
questions. You must put all answers and definitions into your own words for full credit.
16-1: Genes and Variation
Define the following terms.
1. Gene pool:
2. Relative frequency:
3. Singe-gene trait:
4. Polygenic trait:
5. List and describe the two main sources of genetic variation.
Source
Description
a.
b.
6. How is evolution defined in genetic terms?
7. How does the range of phenotypes differ between single-gene traits and polygenic traits?
8. How are allele frequencies related to gene pools?
9. A group of individuals of the same species that can interbreed is a(an) _______________.
10. All of the genes in a populations are called a(an) _________________________.
11. The number of times that an allele occurs in a gene pool compared with the number of
times other alleles for the same gene occur is called the __________________________.
12. Why do mutations occur?
13.
14. How many black alleles are in the gene pool? __________________
15. How many brown alleles are in the gene pool? __________________
16. Use the data below to draw a bar graph showing the frequency of heights in a group of
students. Use a ruler!
17. What type of trait is height?
A color mutation occurred in a brown mouse population, causing darker fur. The table below
shows how the population changed over the next 30 generations.
18. What is happening to the relative frequencies of the light and dark fur color alleles in the
table above?
19. What might cause the change shown in the table in question 14?
20. A particular gene pool contains two alleles, G and g for an inheritable trait. If allele G has
a relative frequency of 42%, what is the relative frequency of allele g?
16-2 Evolution as Genetic Change
21. If a trait made an organism less likely to survive and reproduce, what would happen to the
allele for that trait?
22. If a trait had no effect on an organism’s fitness, what would happen to the allele for that
trait?
23. List and describe the 3 ways that natural selection can affect the distributions of
phenotypes.
Type of Selection
Description
a.
b.
c.
24. An increase in the average size of beaks in Galápagos finches is an example of
_______________________ selection.
25. Random change in allele frequencies in small populations is called
_______________________.
26. A situation in which allele frequencies change as a result of the migration of a small
subgroup of a population is known as the ________________________.
27. Describe the founder effect.
28. Give an example of the founder effect.
29. Describe the Hardy-Weinberg Principle.
30. What is genetic equilibrium?
31. List the 5 conditions required to maintain genetic equilibrium from generation to
generation.
a.
b.
c.
d.
e.
16-3 The Process of Speciation
32. What is speciation?
33. What does it mean for two species to be reproductively isolated from each other?
34. On the lines provided, use the numbers 1-6 to indicate the order in which the following
events occurred in the speciation of the Galápagos finches.
a. _____ changes in the gene pool
b. _____ continued evolution
c. _____ founders arrive
d. _____ reproductive isolation
e. _____ separation of populations
f. _____ ecological competition
35. List and describe 3 types of reproductive isolation that lead to speciation can occur.
Type of Reproductive Isolation
Description
a.
b.
c.
36. Identify which mechanism of reproductive isolation is being described.
a. Peacocks have showy tail feathers, which
they use to try and attract a female peahen
in an attempt to reproduce.
b. Female crickets will only respond to the
mating songs of males of their own
species.
c. Two species of deer mice are separated
by a river.
d. Female poison dart frogs prefer to mate
with male frogs of their same color.
e. The blue-headed wrasse (a reef fish) in the
Atlantic ocean is separated from the
Cortez rainbow wrasse in the Pacific by
the Isthmus of Panama.
f. Male and female albatrosses engage in
elaborate “dancing” displays to evaluate
possible mates.
g. One species of toad mates in early
summer while another species of toad
mates in late summer.
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37. Supposed that a drought on an island eliminates all but plants that produce large, tough
seeds. All the finches on the island have very small beaks. How might this environmental
change impact the survival of this finch population?