SAMPLE MIDTERM EXAM QUESTIONS

BIO 303 Section 101 (Sinclair/Bradfield)

You should be able to define, or briefly explain, the following terms (not a complete list). Any of these could be a “short” (quarter-page or less) question.

Intro and Natural selection

Fitness

Natural selection

Polymorphism

Phenotype

Kin selection

Sexual selection

Hamilton’s rule

Life history

1. r-selection

2. K-selection

3. C-, S-, and R-selection

4. little r (r)

5. r_max

6. R₀

7. Stress and Disturbance

8. Life history

9. Survivorship

10. Generation time

11. Cohort

Population dynamics (we may not get to all these before the exam)

1. Life table

2. Survivorship

3. Age-specific Mortality

4. Age-distribution, cohort and time-specific life table

5. Fecundity rate

6. Stable age-distribution

Know the major contributions of people discussed in class (eg., Darwin, Malthus, Lotka)

Other short-type questions (half-page each, or less)

Natural selection

1. An ecologist was investigating the distribution of a herbaceous plant on a sand dune system at Long Beach on Vancouver Is. He noted that the species was most abundant on the dry upper slopes and tops of the dunes and became progressively less abundant on the wetter lower slopes. Measurements showed a strong correlation between the abundance of the species and soil moisture. He concluded that “soil moisture determines the abundance of the species on this dune system.”

a. Was he justified in making this conclusion? Explain your answer.

b. Describe the experiment you would do to test the hypothesis that “soil moisture determines the abundance of the species on this dune system.”

2. Researchers studying two lion populations found that females in population A had an average of 4 young per year, and females in population B had an average of 6 young per year. The researchers also found that lions in population A had, on average, higher fitness than lions in population B. How could this occur?

3. How does the handicap principle explain female preference for costly male ornaments?

4. Snowshoe hares employ an anti-predatory strategy of hiding in brush for a portion of the day. Hares that hide for 6 hours per day incur a fitness cost of 0.3 units due to lack of foraging time, but they gain a fitness benefit of 0.4 units due to increased survival odds. Hares that hide for 8 hours per day incur a cost of 0.4 units but gain 0.6 units. Which is the more optimal fitness strategy and why?

5. In arctic ground squirrel populations, adult females are more likely to give alarm calls than adult males. If alarm calls are favored by kin selection, why might this difference occur?

6. Is it possible for a trait to be selected for if it puts the survival of the population at risk (for example, cannibalism)? Why or why not?

Life history

1. Explain why an organism can have a higher r-value, yet have a lower r_max, than another organism.

2. In 3 or 4 lines describe the conditions under which the 'S' life history pattern (as per J.P. Grime) would evolve.

3. Explain why an organism, in order to increase its r_max, is better to decrease its generation time rather than producing more offspring.

4. What value of R₀ for a population would be most consistent with an observed value of r_a=0 in that same population? Explain your answer in words (the question cannot be answered by calculation).

5. [Answer all of a-d.] A population exhibits the traits shown in the life table below. Assume that breeding occurs late in the growing season.

age-class (x)	lx	bx
0	1.0	0
1	0.6	0
2	0.35	2
3	0.1	2
4	0.03	3
5	0	---

a) Is this population increasing its density? Show any calculations below (you may also use the blank columns in the table above to keep track of your calculations, if you wish).

b) Can this population maintain itself (say, over many generations)? Why or why not?

c) If you observed 180 age-class-1 individuals in year 0 (zero), how many age-class-3 individuals would you expect to observe in year 2?

d) Would this population’s growth-potential change if its reproduction began in age-class 1 instead of in age-class 2? If so, about how much? (Assume for this section that the sequence of fecundities, “2,2,3”, stays the same, just “bumped up” one age-class, and age-class 4 now does not breed at all.)

6. Compare and contrast the costs and benefits of “residency” versus “dispersal” as alternative life history strategies in the following types of habitats:

- constant (in time) and continuous (in space)

- unpredictable (in time) and isolated (in space)

7. Explain briefly the main similarities and differences between a cohort and static life table.

8. Try the following questions from your textbook (Krebs 5^th): 10.3, 10.5, 10.6.

Life tables

1. Explain the conditions required to achieve a stable age-distribution.

2. Explain the difference between a cohort life table and a time-specific life table

3. Explain the different types of survivorship curves and give examples.