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Midterm I
Biology 359
Evolution
Wednesday October 20, 2010 (5:30-6:50 pm)
Name: ______________________________________
Student Number:______________________________
This exam is composed of two sections. Please read the instructions for each section CAREFULLY and
answer the questions using only material from the lectures, lecture notes, movies and text.
Section I: Multiple Choice and True/False. 35 questions (1 mark each, total 35 marks). Place your
answers on the computer card. Note: only the computer cards will dictate your results.
Section II: Short answer/ calculations. 20 marks total. Write your answer in the space provided. Write
legibly. If we can’t read it, we can’t mark it.
DO NOT WRITE ANSWERS ON THE BACK OF THE PAGES- THEY WILL NOT BE
MARKED. This exam has a total of 10 pages including this page. Make sure that you have all 10 pages
You are permitted the use of a calculator on this exam
Name: _______________________ Student #: ___________________________
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Part I. Multiple Choice. Choose the best possible answer to the following questions or statements.
Don’t forget to put your answers on the computer card. (1 mark each, total 27 marks)
1. The relative dating time scale is based on a number of geological principles. Which of the following
statements is incorrect with respect to these principles?
A) Younger rocks are deposited horizontally on older rocks
B) Earlier fossil forms are always more complex than more recent forms
C) Sedimentary rocks were originally deposited in a horizontal
position
D) Inclusions are older than the rocks they are deposited in
E) None of the above
2. Disruptive selection is expected to:
A) Have little or no affect on the variance of a trait, and increase its average value
B) Increase the variance of a trait, and have little or no affect on its average value
C) Decrease the variance of a trait, and increase it’s average value
D) Increase the variance of a trait, and decrease it’s average value
E) None of the above
3. Which of the following is correct about scientific hypotheses?
A) They can always be incorporated into scientific theories
B) They provide a descriptive generalization about the natural world
C) When extensively tested and verified, they can be taken as the final truth
D) All of the above
E) None of the above
4. Rates of mutation per generation can potentially differ among organisms as a result of:
A) Differences in generation time
B) Differences in DNA repair efficiency
C) Differences in the number of cell divisions leading to gamete formation
D) All of the above are correct
E) Only b and c are correct
5. The evolution of globin genes provide an excellent example of _____________.
A) Duplication of genes
B) Inversion of genes
C) Reciprocal translocation of genes
D) Polyploidy
E) None of the above
Name: _______________________ Student #: ___________________________
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6. Which of the following statements concerning genetic drift is correct?
A) Genetic drift is effective at removing deleterious alleles when population size is large
B) Genetic drift changes genotype frequencies, but does not affect allele frequencies
C) Genetic drift will always oppose natural selection when population size is small
D) Genetic drift can either work with, or against natural selection when population size is small
E) Genetic drift is always more powerful than natural selection when populations are very large
7. Which of the following statements characterizes neutral point mutations?
A)
B)
C)
D)
E)
They always lower an organisms fitness
They are always synonymous
They affect an individuals ability to grow
All of the above
None of the above
8. The documentary ‘Great Transformations’ suggested that which of the following provides evidence that
whales evolved from land mammals
A) The movement of the spine
B) The internal morphology of the tail fin
C) The internal morphology of the pelvic fins
D) The location of several internal organs
E) Both B and C above are correct
9. A locus in a population possesses two alleles (A1 and A2). The frequency of allele A2
is 0.75. If this population is known to be inbreeding, which of the following would
be expected?
A) The frequency of A1A2 heterozygotes must be less than 0.3750
B) The frequency of A1A2 heterozygotes must be less than 0.1875
C) The frequency of A1A1 homozygotes must be greater than 0.1250
D) Both A and C above would be expected
E) Both B and C above would be expected
10. Darwin's concept of Natural Selection is closest in meaning to which of the following statements?
A) In any population variation exists and much of this variation is heritable.
B) Individuals with more favorable traits are more likely to reproduce, and these inherited
favorable traits become more common in succeeding generations.
C) Individuals of a species naturally select the habitat and niche to which they are best suited.
D) There is random mating in a population and no selection for or against either member of an
allelic pair.
E) There is never any variation in a population, which is why natural selection is powerful
11. Which of the following could occur as a result of inbreeding?
A) Violations of the Hardy-Weinberg principle
B) An increase in the number of homozygotes
C) A reduction in the number of heterozygotes
D) All of the above
E) A and B only
Name: _______________________ Student #: ___________________________
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12. When the selective loss of a deleterious allele and its rate of re-entry into a population are equal, we
have _________________.
A) Mutation-selection balance
B) Mutation equilibrium
C) Mutation-substitution balance
D) Selection-substitution balance
E) Deleterious allele equilibrium
13. Genetic variation can be maintained in a population as a result of __________________.
A) Mutation
B) Heterozygote superiority
C) Deleterious alleles hiding in heterozygotes
D) All of the above
E) only A and B above
14. Consider two groups of populations, group A and group B, with 100 populations in each group. All
populations within group A consist of 1000 individuals, and all populations in group B consist of 20
individuals. If genetic drift is the only force affecting these populations, which of the following statements
will be false after many generations?
A) Populations within group A will be more similar to each other with respect to allele frequencies
than those within group B
B) On average, heterozygosities will be lower in group B
C) On average, homozygosities will be higher in group A
D) A B and C above are all false
E) None of the statements above are false
15. The graph to the right shows the distribution of beak depth in a population of finches on Daphne
Major. If stabilizing selection is in operation, which portion(s) of the population will be selected for and
are most likely to have their genes represented in the next generation?
A) A
B) B
C) C
D) A and C
E) A, B and C
16. Natural selection acts directly on __________.
A) The phenotype
B) The genotype
C) The entire genome
D) Each allele
E) The entire gene pool
Name: _______________________ Student #: ___________________________
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17. Cystic fibrosis is caused by a loss-of-function mutation. Before the advent of modern medicine many
individuals with CF did not survive to a reproductive age, however this mutation is still maintained within
the population. What is the cause of this?
A) Heterozygote superiority
B) Genetic drift
C) Heterozygote inferiority
D) Inbreeding
E) Migration
18. Which of the following will not result in violations of the Hardy-Weinberg Principle?
A) Self fertilization
B) Mating among individuals that are closely related
C) An infinitely large population size
D) Individuals with certain genotypes having much higher survival rates than others
E) All of the above will result in HW violations
19. Which of the following can reduce heterozygosity in a population?
A) Genetic Drift
B) Inbreeding
C) Migration
D) All of the above
E) Only A and B above
20. It was observed that genotype frequencies in a population changed as juveniles developed into adults,
which one of the following could account for this?
A) Genetic Drift
B) Inbreeding
C) Natural Selection
D) All of the Above
E) None of the Above
21. Which of the following statements concerning natural selection and genetic drift is/are correct?
A) Natural selection acts randomly, and genetic drift is non-random
B) Both genetic drift and natural selection will always result in adaptive evolution
C) Genetic drift is random and natural selection is non-random
D) All of the above
E) None of the above
22. The law of succession pertains to which of the following statements?
A) Species that inhabit Australia today will be more similar to fossils found in Australia
than fossils from South America
B) Younger fossils will be found in younger geological formations
C) Older fossils will be found in older geological formations
D) All of the Above
E) None of the above
Name: _______________________ Student #: ___________________________
23. The anti HIV drug AZT uses which of the following mechanisms to reduce infection?
A) It attaches to the virus, causing it to become non functional
B) It prevents the virus from entering host cells by attaching to membrane proteins
C) It replaces the amino acid alanine in viral peptide chains, causing them to lose function
D) It interferes with viral DNA replication by replacing the nucleotide thymidine
E) It stimulates immune system cells, causing them to produce more antibodies
24. The notion that because science describes the way that the world is, it also describes the way that the
world should be, is known as the _______________.
A)
B)
C)
D)
E)
Naturalistic fallacy
Paradigm of scientific philosophy
Central dogma of scientific interpretation
Second principle of scientific inference
First principle of proximal cause and effect
25. An assumption in radiometric dating is that the initial ratio of parent to daughter isotopes is
known. In the case of potassium/argon dating, this assumption can be tested by:
A)
B)
C)
D)
E)
Examining the potassium/argon content in very recent lava flows
Mass spectrophotometric analysis of recent meteor impact sites
Comparing the potassium /argon content in living organisms to the content in fossils
Comparing the potassium/ argon content of rocks occurring on the moon to those on Earth
Examining the potassium/ argon content of rocks that have no inclusions
26. Which of the following cannot result in the “evolution” of a population on its own?
A)
B)
C)
D)
E)
Genetic drift
Inbreeding
Natural Selection
Migration
All of the Above can result in the evolution of a population
27. Which of the following individuals contributed the most to evolutionary biology?
A)
B)
C)
D)
E)
Reverend William Paley
Sarah Palin
Little Cindy Loo Who, who was no more than two
The Man from Glad
Charles Darwin
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Name: _______________________ Student #: ___________________________
True/False. Indicate whether each of the following statements is true or false. Part, but not all of the
information may be true, and if so the answer is false. Place your answer on the computer card
(1 mark each, total 8 marks).
28. In the absence of violations of the Hardy-Weinberg principle, all genotype frequencies will be
equal.
a. True
b. False
29. In Lamarck’s book, Principles of Geology, he proposed the law of superposition.
a. True
b. False
30. We refer to taxa as being “higher or lower” because higher taxa are superior and more advanced than
lower taxa
a. True
b. False
31. The principle of uniformitarianism states that the geological processes that we see today are the same
as those that operated in the past.
a. True
b. False
32. HIV first infected humans before the time of the Roman Empire, and remained at an extremely
low frequency until the early 1980s.
a. True
b. False
33. In science, a theory is a descriptive generalization about how some aspect of the natural world
behaves under specified circumstances.
a. True
b. False
34. Heterozygote superiority is a form of balancing selection.
a. True
b. False
35. Characteristics acquired by an organism during its life can be genetically inherited by its offspring
a. True
b. False
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Name: _______________________ Student #: ___________________________
Part II: Please answer the questions in the spaces provided.
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1) For each of the following statements, fill in the appropriate CORRECTLY SPELLED word or
words (1 mark for each blank, 10 marks total). Mildly misspelled = 0.5, Seriously misspelled = 0
A) A loss in genetic variation as a result of sampling error when a new population is established
from a parent population is referred to as the______________________________.
B) The rudimentary limbs of a snake are an example of a ___________________________.
C) The substitution of a pyrimidine with a purine is a point mutation
referred to as a __________________.
D) ___________________ is the process that results in the production of haploid gametes from
diploid parent cells
E) Suppose we have a graph that gives parents midpoint height on the x-axis, and the
average height of their offspring on the y-axis, the slope of this line will estimate
the______________________ of height
F)__________________________ refers to a decrease in the average fitness of individuals within
a population due to an increase in homozygous recessive conditions, which result from mating
among closely related individuals.
G) A sharp reduction in population size that can reduce genetic variation in a population is
referred to as a ___________________________.
H) Conservation biologists will sometimes introduce individuals from distant populations into a
small population to reduce the negative genetic consequences of small population size. The
reduction of these negative consequences is known as the_____________________________.
I) _______________________ is the study of ancestor/ descendent relationships.
J) Conservation biologists are concerned about small population size because drift can fix
alleles, reducing heterozygosity, genetic variation and _____________________________.
Name: _______________________ Student #: ___________________________
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2. In seven (7) words or less, define Evolution [1 mark]
3. Words of the Day Bonus Marks: Briefly define two (2) of the following three words: Indolent,
Impecunious, Behoove [2 marks each, 4 marks total]
4) Suppose that a certain population of 100 individuals possesses two alleles (A and B) at a certain locus,
and initially consists of the following numbers of genotypes: AA = 9, AB = 42, BB= 49.
a) Calculate the initial frequencies of alleles A and B (2 Marks)
4b) Now suppose that 16 individuals with genotype BB do not survive to reproduce. Calculate the new
allele frequencies among the remaining individuals that do reproduce. Assuming that these remaining
individuals mate randomly, calculate the new genotype frequencies in the next generation. Use the
following headings to organize your calculations (continued on next page).
New Allele Frequencies (2 Marks)
Name: _______________________ Student #: ___________________________
New Genotype Frequencies (2 Marks)
2. Explain what is meant by the following statement: “Natural selection cannot respond to future
environmental changes” any part of your answer written outside of the box will not be marked
[3 marks]
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