BIOLOGY 432 Name _____________________ Midterm I - 19 October 1998
PART I. Multiple choice questions – (3 points each, 24 points total).
1. Charles Darwin, the father of evolutionary theory, hypothesized that evolution occurred via a process called natural selection, which of the following best describes this process? A. adaptation
B. descent with modification C. taxation without representation D. survival of the fittest
E. ontogeny recapitulates phylogeny
2. Natural Selection is the driving force behind evolution, which of the following is NOT a correct concept relating to natural selection?
A. change in the trait distribution of populations B. acts at the level of the individual
C. forward looking process
D. operates on existing traits or phenotypes E. is directed and purposeful
3. Charles Darwin described the theory of evolution through the process of natural
selection in his book, “The Origin of Species,” but what he did not yet understand (and hopefully you do) was the underlying mechanism. What was this mechanism?
A. extinction B. adaptation C. mutation D. phylogeny E. random drift
4. During his career, Charles Darwin had to go to sea to conduct field studies. During this oceanographic cruise on the vessel the HMS Beagle he visited which Islands that later played a critical role with his theory of evolution?
5. Methods in evolutionary analysis focus on questions of adaptation and diversity, which of the following is NOT a feature found among these studies?
A. natural history reconstruction B. comparative method
C. hypothesis testing
D. maximize both precision and accuracy E. resolve complicated questions
6. Over time even the most highly conserved gene sequence will fix mutations. Eventually, given sufficient time what will the percent of identical nucleotides be at any given
position?
A. 25%
B. 50%
C. 75%
D. 100%
E. none of the above
7. When considering the neutral theory of molecular evolution, which of the following is/are correct assumptions of this model?
A. positive selection is excluded B. population size does not matter
C. pseudogenes are useful in measuring evolution rates D. genetic drift is the dominant feature
E. all of the above
8. The definition of a species is a multifarious concept, which of the following is NOT applicable to the species concept?
PART II. Short answer questions – (Number of points in parentheses, 61 points total). 9. (6 points) Why is genetic drift enhanced by population bottlenecks?
10. (6 points) What are the two most important consequences of inbreeding in a population?
11. (8 points) The reinforcement model of allopatric speciation predicts a certain order in which prezygotic and postzygotic barriers should evolve. Under this model, which type of barriers should arise first, and which should rise second?
im
e
im
e
A B
13. (6 points) What are the three major forcing functions or mechanisms behind the diversity of genes and allelles? Briefly explain each answer.
14. (6 points) Point mutations are a major source of genetic change. List and describe three different concepts that describe and relate directly to the different potential types of point mutations:
15. (3 points) Humans have approximately 3.4 billion nucleotides in their genome, name an organism that has a larger genome?
17. (12 points) Grasshoppers (Melanoplus punctipes), all living in a field were sampled twice during the year and scored for color pattern. Color pattern is due to a single gene with two alleles: spotted (A1A1), stippled (A1A2), and solid (A2A2). The population was first sampled
in the spring, soon after grasshoppers had hatched from overwintering eggs. At that time, the allele frequencies were: frequency of A1 = 0.4, and frequency of A2 = 0.6, and genotype frequencies agreed with Hardy-Weinberg expectations. The second sampling took place in August, when reproduction was at its peak. In this species, eggs are laid in the fall and hatch in the spring. Grasshoppers reach maturity and reproduce in late summer and then die. Adjacent fields and woods were also known to contain grasshoppers, but were not sampled.
Spotted Stippled Solid
A1A1 A1A2 A2A2
August sample (# individuals) 120 350 530
A. Calculate allele frequencies and expected genotype frequencies for the August sample.
B. Are genotype frequencies in Hardy-Weinberg equilibrium in late summer? If not, which genotype(s) differ from their expected frequencies, and in which direction?
PART III. Short Essay – (Number of points in parentheses, 15 points total).