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Final Test Review - Evolution
1. What are the statutes of the Hardy-Weinberg Equilibrium (HWE)? (There are 5)
a. Populations must be large
b. Mutations must not occur
c. There must be no immigration or emigration
a. Populations must be isolated so there is no gene flow
d. Reproduction must be random
e. There must be no natural selection
2. If all conditions of the HWE are met, what does this say about the population?
The population is not evolving if all the HWE conditions are met
3. What is the HWE? What do the letters mean?
p2 + 2pq + q2 = 1 and p + q = 1, where p = frequency of the dominant allele and q
= frequency of the recessive allele.
4. If a population is in HWE and 34% of the population expresses the recessive trait,
what are the allelic frequencies and the phenotypic frequencies?
34% = recessive = q2, so .34 = q2
thus q = √.34 = .58
If q = .58, and p + q = 1, then p = 1 - .58 = .42
So, allelic frequencies = q = .58 and p = .42
Thus, using p2 + 2pq + q2 = 1, plug in numbers to get phenotypic freq.
(.42)2 + 2(.42)(.58) + (.58)2 = 1
Genotypic Frequencies = p2 = .176, pq = .487, q2 = .336
5. If another population is in HWE and 16% of the population is homozygous dominant,
what are the allelic and phenotypic frequencies of this population?
16% = homozygous dominant = p2 so
p = √.16 = .40
If p = .40
then q = 1 - .40 = .60
So, allelic frequencies = q = .60 and p = .40
Thus, using p2 + 2pq + q2 = 1, plug in numbers to get phenotypic freq.
(.40)2 + 2(.40)(.60) + (.60)2 = 1
Genotypic Frequencies = p2 = .16, pq = .48, q2 = .36
6. What has happened to a population who has had changes in the allelic frequencies
over time?
The populations is said to have evolved
7. What is the difference between a vestigial structure and an analogous structure? Give
an example of both.
Vestigial Structure – A structure that has seemingly lost any function – appendix
Analogous Structure – A structure that has shared anatomy and similar function in
two separate species – Wing of a bird & bat.
8. Contrast Convergent and Divergent evolution.
Convergent – Where 2 separate species gradually become closer due to natural
selection, can eventually end up as same species
Divergent – Where 1 species speciates, or becomes 2 separate species
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9. What is Natural Selection and who was the founding father?
Charles Darwin
10. What are two other terms we can use that mean a population is undergoing divergent
evolution?
Speciation & Disruptive selection
11. At what point does a population undergoing speciation become 2 new species?
@ the point the two populations can no longer interbreed successfully
12. What is the difference between adaptation (response to the environment) and
evolution?
Adaptation = An individuals’ response to the environment, such as putting on
more clothes when its cold.
Evolution = A species’ response due to long term changes in the environment –
The evolution of placenta in mammals
13. What is the difference between immigration and emigration?
Immigration – Movement of individuals into a population
Emigration – Movement of individuals out of a population
14. What is the significance of immigration and emigration in terms of evolution?
This causes gene flow, which will cause the evolution to evolve
15. Draw a graph for stabilizing selection, disruptive selection, and directional selection.
16. Distinguish between gene flow, genetic drift & a bottleneck effect. What are all these
processes of?
Gene flow – Movement of new genes/alleles into & out of the population
Genetic Drift – Changes in the genotypic frequencies due to CHANCE
Bottlenecks – A natural disaster causes a random decrease in a populations
numbers, leaving a very small surviving population – think Forest fire &
surviving deer species
Complete each statement:
17. The wings of a butterfly and a bat are analagous structures.
18. Natural selection is also known as survival of the fittest.
19. The number of times an allele occurs in a gene pool compared with the number of
times other alleles for the same gene occurs is genetic or allelic frequency.
20. All individuals of the same species in a given area form a population.
True/False – make the statement correct if it is false by changing the underlined word.
21. Genetic drift alters the gene pool of a small population.
True
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22. The blending of peppered moths into their background is an example of mutation.
Camouflage or species adaptation, which we call evolution by natural selection
23. The variations upon which natural selection depends are gene mutations and gene
recombination.
True
24. Gene pools can change in the absence of natural selection.
True
25. In which type of selection are the very light-colored and the very dark-colored
butterflies eliminated?
Stabilizing Selection
26. Which type of selection acts against the intermediate-colored butterflies and favors
the light-colored and dark-colored butterflies?
Disruptional or Diversifying Selection
27. Suppose artificial selection greatly increases the number of dark-colored butterflies.
Which type of selection curve will occur among the butterflies?
Directional, in favor of an extreme phenotype
28. Which type of selection occurred among the peppered moths of England following
the Industrial Revolution that stained London’s tree trunks dark brown?
Directional, in favor of the extreme phenotype, Brown