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Chapter 23: Microevolution: Evolutionary Change in Populations
Name
AP Biology
Date
Mr. Mennecke
1. The genetic description of an individual is its genotype, whereas the genetic description of a
population is its
a) phenotype
d) gene pool
b) gene pool
e) genetic drift
2. If a population’s allele frequencies remain constant from generation to generation
a) the population is undergoing evolutionary change
b) the population is said to be at genetic equilibrium
c) evolution has taken place
d) directional selection is occurring, but only for a few generations
3. According to the Hardy Weinberg principle
a) allele frequencies are not dependent on dominance or recessiveness but remain
essentially unchanged from generation to generation.
b) the sum of allele frequencies for a given locus is always greater than 1.
c) Gene frequencies must be 0.
d) Allele frequencies change from generation to generation.
4. What is the correct equation for the Hardy Weinberg principle?
a) p2 + 2pq + 2q2 = 1
d) p2 + pq +q2 = 1
2
2
b) p + 2pq +2q = 1
e) p2 + 2pq +q2 =1
5. Which of the following is not an evolutionary agent that causes change in allele frequencies?
a) Mutation
d) random mating
b) natural selection
e) gene flow from migration
6. Mutation
a) leads to adaptive evolutionary change
b) adds to the genetic variation of a population
c) almost always benefits the organism
d) a and b are correct
7. Which of the following is not true of natural selection?
a) It can preserve preferable traits and eliminate undesirable ones.
b) Offspring better adapted to the environment make up a larger proportion of the next
generation.
c) It directs the course of evolution by preserving the traits acquired during an individual’s
lifetime.
d) It acts on a population’s genetic variability, which arises through mutation.
8. Which is an example of sexual dimorphism?
a) A female Canadian goose will sit on her eggs while the male guards the female from afar.
b) Male and female ladybugs can both be red with black spots.
c) A male cardinal is red and showy while the female is drab and brown.
d) Male tigers have a similar banding pattern of black stripes.
9. Individuals don’t evolve; ________ do.
a) communities
c) animals
b) ecosystems
d) populations
10. Genetic variation can give rise to variation in _______ traits.
a) Morphological
c) behavioral
b) Physiological
d) all of the above
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Chapter 23: Microevolution: Evolutionary Change in Populations
11. The following graph represents which mode of natural selection?
a) directional
b) stabilizing
c) diversifying
d) sexual dimorphism
12. The following graph represents which mode of natural selection?
a) directional
b) stabilizing
c) diversifying
d) sexual dimorphism
later
now
now
later
Matching:
13. gene flow
14. natural selection
15. mutation
16. genetic drift
a) source of new alleles
b) changes in a population’s allele frequencies due to
chance alone
c) immigration, emigration change allele frequencies
d) differences in survival and reproduction among
different individuals
17. A gene pool consists of
a) all the alleles exposed to natural selection
b) the total of all alleles present in a population
c) the entire genome of a reproducing individual
d) all the gametes in a population
18. In a population with two alleles, B and b, the allele frequency of B is 0.7. What would be the
frequency of heterozygotes if the population is in Hardy-Weinberg equilibrium?
a) 0.7
c) 0.42
b) 0.49
d) 0.21
19. In a population that is in Hardy-Weinberg equilibrium, 16% of the individuals show the recessive
trait. What is the frequency of the dominant allele in the population?
a) 0.84
c) 0.4
b) 0.36
d) 0.6
20. There are five conditions that must be met to maintain the Hardy-Weinberg equilibrium. Of the
following, which is not one of the conditions?
a) no natural selection
d) gene flow between populations
b) random mating
e) very large population size
21. There are five conditions that must be met to maintain the Hardy-Weinberg equilibrium. Of the
following, which is not one of the conditions?
a) no natural selection
c) isolation from other populations- no gene flow
b) random mating
d) very small population size
22. In the graph to the right, the solid line represents a trait’s distribution in a population before
natural selection. The dotted line shows the trait’s distribution after selection. The following
graph represents which mode of natural selection?
a) directional
c) sexual dimorphism
b) stabilizing
d) diversifying
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Chapter 23: Microevolution: Evolutionary Change in Populations
23. The average length of jackrabbit ears decreases the farther north the rabbits live. This variation
is an example of
a) a mutation
c) genetic drift
b) variation
d) diversifying selection
24. Selection acts directly on
a) phenotype
b) genotype
c) each allele
d) the entire gene pool
25. As a mechanism of microevolution, natural selection can be most closely equated with
a) random mating
c) differential reproductive success
b) genetic drift
d) gene flow
26. Most of the variation we see in coat coloration and pattern in a population of wild mustangs in any
generation is probably due to
a) new mutations that occurred in the preceding generation
b) sexual recombination of alleles
c) geographical variation within the population
d) environmental effects
27. A bottleneck tends to
a) decrease mutations
b) increase mutations
c) allow gene frequencies normally low in number to have a larger representation in a
surviving population
d) allow gene frequencies to reach zero
28. Bacteria can adapt to changes in the environment by means of mutation alone because
a) they are so small in size.
b) their populations are very isolated from one another.
c) a bacterium is much more likely to mutate than a larger organism.
d) they multiply so rapidly.
29. The smallest unit that can evolve is a
a) species.
b) genotype.
c) population.
d) gene
30. The ultimate source of all genetic variation is
a) natural selection.
c) asexual reproduction.
b) genetic drift.
d) mutation.
31. Sexual recombination occurs when chromosomes are shuffled during _____ and fertilization.
a) Mitosis
c) mutation
b) genetic drift
d) meiosis
32. A geneticist mixed together many different kinds of fruit flies-some with long wings, some with
short wings, some with red eyes, some with brown eyes, and so on. He allowed the flies to feed,
mate randomly, and reproduce by the thousands. After many generations, most of the flies in the
population had medium wings and red eyes, and most of the extreme types had disappeared.
This experiment appears to demonstrate
a) genetic drift.
c) diversifying selection
b) stabilizing selection.
d) geographical variation.
33. Rabbits living farther north tend to have smaller ears allowing them to lose less body heat than
larger-eared rabbits, which tend to die earlier in life. This is an example of
a) a cline.
c) heterozygote advantage.
b) polymorphism.
d) natural selection.
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Chapter 23: Microevolution: Evolutionary Change in Populations
34. Blue poppies native to China are grown at a plant-breeding center in California, where those with
the thickest leaves survive and reproduce best in the drier climate. This evolutionary adaptation of
the poppies to their new environment is due to
a) genetic drift.
c) directional selection
b) stabilizing selection.
d) diversifying selection.
35. Critics like to point out that the theory of evolution is flawed because it is based on random
changes-mutations. They say that a random change in an organism (or a car or a TV set) is likely
to harm it, not make it function better. What logical statement could a defender of evolution make
in reply to this criticism?
a) Mutation is random, but natural selection is not.
b) Mutation has nothing to do with evolution.
c) Organisms evolve according to what adaptations they need to survive.
d) Mutations are not actually random, but regularly scheduled events.
36. Each of us is part of the ongoing evolution of the human species. Which occurrence would have
the greatest impact on the future biological evolution of the human population?
a) You work out every day so that you stay physically fit and healthy.
b) A mutation occurs in one of your skin cells.
c) You move to Hawaii, the state with the longest life expectancy.
d) A mutation occurs in one of your sperm or egg cells.
37. The processes of
and
generate variation, and
adaptation to the environment.
a) mutation . . . sexual recombination . . . genetic drift
b) genetic drift . . . mutation . . . sexual recombination
c) mutation . . . natural selection . . . sexual recombination
d) mutation . . . sexual recombination . . . natural selection
produces
38. Birds with average-sized wings survived a severe storm more successfully than other birds in the
same population with longer or shorter wings. This illustrates
a) the founder effect.
c) gene flow.
b) stabilizing selection.
d) diversifying selection.
39. Which scenario would most likely result in microevolution of a population of humans?
a) Only random mating took place in all people that reproduced in North America.
b) A colony of humans on the moon was isolated from earth.
c) The incidence of skin cancer in adults over age 40 rose significantly.
d) All of the people in Georgia were killed in a natural disaster.
40. Which of the following is the best example of gene flow.
a) A polyploid plant develops.
b) Genes are shuffled by crossing over of chromosomes during meiosis.
c) An earthquake results in the formation of a canyon splitting a population of toads apart.
d) Wind blows pollen from one population of plants to another and cross fertilization occurs.
41. Stabilizing selection
a) favors intermediate variants in a population.
b) prevents mutations from occurring.
c) occurs when some individuals migrate to an area with different environmental conditions.
d) can only take place in species exhibiting sexual dimorphism.
42. According to the Hardy-Weinberg theorem, the frequencies of alleles in a population would
remain constant if
is the only process that affects the gene pool.
a) mutation
c) genetic drift
b) sexual reproduction
d) natural selection
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Chapter 23: Microevolution: Evolutionary Change in Populations
43. In the Hardy-Weinberg theorem p2 represents
a) the total alleles in the gene pool.
b) the heterozygous dominants in the gene pool.
c) the homozygous recessives in the gene pool.
d) the homozygous dominants in the gene pool.
44. In the Hardy-Weinberg theorem, 1 represents
a) The total alleles in the gene pool.
b) the heterozygous dominants in the gene pool.
c) the homozygous recessives in the gene pool.
d) all the possible phenotypes in the gene pool.
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