BIO360 Exam 3 Key
(Questions are identical in Code 16, but in a different order)

Multiple Choice Questions (2 pts each)

1. The population of Greater Prairie Chickens in Illinois was reduced first by habitat loss, and then:
A. overhunting
B. loss of genetic diversity
C. disease
D. predation

2. Effective population size, Ne, is usually ________ the actual (or census) population size.
A. less than
B. equal to
C. more than

3. Inbreeding depression can happen by:
A. expression of deleterious alleles that are otherwise recessive
B. loss of heterozygotes and accumulation of homozygotes
C. A&B
D. None of the above

4. A term used to describe a species interaction that results in the population growth rate of one species increasing and the other species decreasing is:
A. competition
B. herbivory
C. mutualism
D. commensalism
E. ammensalism

5. In the S-I-R model of disease transmission, what value of the basic reproductive ratio, R0, will result in a disease epidemic when a small number of infectious individuals are introduced into the population?
A. R0 = 0
B. R0 < 1 
C. R0 = 1
D. R0 > 1

6. “A condition that is harmful to the host, caused by a parasite or pathogen” defines:
A. disease
B. host
C. infection
D. infectious disease

7. Unlike predators, infectious diseases:
A. are always independently mobile, able to transmit themselves
B. are smaller than their host
C. always cause death of their host
D. are never susceptible to host immunity

8.  “Use of natural enemies (parasites, predators, and disease) to control pest population sizes” defines:
A. biocontrol
B. predation
C. coexistence
D. competition
E. displacement

9. A virus used to control the Eurasian rabbit in Australia became less effective over time because
A. the rabbit evolved resistance
B. the virus killed too many rabbits
C. the virus ran its course, and disappeared
D. Australia’s environment could not support the virus, or the rabbit

10. Before vaccination began, infection by measles in London, England rose every two years, and the rise can be explained by:
A. The lifespan of measles virus
B. Immunity of humans to measles
C. Birth rates of susceptible children needed to sustain the disease
D. Natural fluctuations in temperature and precipitation

11. In predation experiments with protozoans, the predator and prey could coexist when:
A. unlimited food for the prey species
B. food for the prey species was limited
C. the structure of their environment was more variable or the size larger
D. their environment was small and uniform
E. B&C

12.  The mathematical models for predators and prey are based on which of the following?
A. energy balance equation
B. exponential population growth equation
C. logistic population growth equation
D. life table equation

13.  In Australia, prickly pear plants were controlled by what consumer?
A. cows
B. rabbits
C. the cactus moth, Cactoblastis cactorum
D. kangaroos

14. Assumptions of the predator-prey model include that:
A. prey population growth is only limited by predators and by availability of its own food
B. predator is a specialist, consuming only this prey
C. predator population can consume very small number of prey

15. In a graphical solution to the predator-prey model, from nearly any point where the two populations start at sizes greater than zero, the outcome of the interaction will be:
A. the predator consumes all prey until none remain
B. prey escape predators, causing predator populations to drop to zero
C. the predator and prey will co-exist
D. the predator and prey population sizes will grow exponentially

16. A maple tree and a dogwood tree are growing next to each other but not touching.  Their root network extends to where each is taking up a substantial amount of nitrogen in the vicinity of the other plant.  This is an example of:
A. exploitative competition
B. interference competition
C. intraspecific competition
D. competitive exclusion

17. Two diatom species are growing in the same pond, and both need silica and phosphorous. These two species will live together (coexist) if
A. one species is the best consumer of both resources
B. both species are limited by silica only
C. each species is a better competitor for a different resource

18. The best competitor is the species that persists
A. at the highest level of a resource in its environment
B. at the lowest level of a resource in its environment
C. when resources are unlimited
D. under any environmental conditions (temperature, rainfall, etc)

19. The mathematical models for competition between species are direct extensions of which of the following?
A. logistic population growth equation
B. exponential population growth equation
C. energy balance equation
D. life table equation

20.  In the competition equations developed by Lotka and others, what does the term αN2 represent?
A. instantaneous rate of population increase of species 1
B. carrying capacity of the environment for species 1
C. reduction of species 1's population growth rate by individuals of species 1
D. reduction of species 1's population growth rate by individuals of species 2

21. Yucca moths do what in or with Yucca plants?
A. pollinate
B. mate
C. feed as larvae on yucca ovaries
D. all of the above

22. When two species have a negative effect on each other through a predator or other enemy, this is termed:
A. predation
B. competition
C. mutualism
D. apparent competition

23. Pollination, and the interaction between a plant and insect pollinator, is what type of mutualism?
A. dispersive
B. trophic
C. defensive
D. mimic

24. Acacia plants with ants have
A. fewer herbivores
B. higher survival
C. lower fecundity
D. higher seed dispersal
E. A&B

25. One butterfly species that mimics another toxic butterfly species
A. is itself always toxic
B. is itself never toxic
C. may be toxic or non-toxic
D. has a different type of defense, not toxicity

26. Coevolution
A. is evolution in two or more species in response to interactions between those species
B. refers to mutual evolutionary response among species
C. fosters a diversity of adaptations
D. explains the close relationship between yucca plants and yucca moths
E. all of the above

27. A basic sequence in the formation of new species is
A. Populations become isolated, they diverge in traits, and then they become reproductively isolated
B. Populations remain together, they diverge in traits, and then they become reproductively isolated
C. Populations become isolated, their traits remain similar, but they become reproductively isolated
D. Populations remain together and become reproductively isolated

28. Populations that remain together, yet become new species, such as the soap bug, experience what type of speciation?
A. vicariance
B. allopatric
C. convergent
D. sympatric

29. Since the Cambrian Explosion 600 million years ago, the number of marine animal families and plant species has
A. decreased
B. remained constant
C. increased
D. increased, and then decreased

30. Whales and hippos
A. were linked as close ancestors by their phylogeny
B. do not share a certain bone, the Astragalus
C. compared to other Arteriodacyls, share the most DNA
D. all of the above

Short Answer or Short Essay Questions
31. List three concepts from population genetics that can lead to loss of genetic diversity: (3 pts)
1. founder effect
2. bottleneck
3. inbreeding
- genetic drift

32. Why would an infectious disease not evolve high virulence (=high population growth rate within a host)? (4 pts)
Infectious disease with high virulence would cause high host mortality.  If mortality occurs too quickly, prior to transmission, the disease population will itself be lost.

33. What are the three corners of the disease triangle? (3 pts)
Host, Pathogen, Environment

34. What do S, I, and R stand for in the SIR model of infectious disease. (3 pts)
Susceptible, Infected, Recovered

34b. If you add S, I, and R, what value do you obtain? (2 pts)
N = the population size

35. Give one example of a pair of interacting species whose populations oscillate (a consistent pattern of rising and falling) through time. (2 pts)
Many examples possible, Lynx-Hare, Human-Measles, and others.

36.  Fill in the following table to indicate whether each species interaction results in a positive, negative, or neutral effect on the population growth rate of the two species involved.  Use a “+” for a positive effect, a “-“ for a negative effect, and a “0” for no effect.  (7 points)
Interaction, Effect on species #1, Effect on species #2
Predation, +, -
Commensalism, +, 0
Herbivory, +, -
Parasitism, +, -
Mutualism, +, +
Interspecific competition, -, -
Disease, +, -
Note: signs could occur in either order and be correct.
37.  Consider the graphic below, representing competition between two species of oaks, red oaks and white oaks:
37a.  What does the α next to the y-axis refer to? (2 pts)
This converts individuals of species 2 into units of individuals of the competitor species 1

37b.  What does the dashed line represent? (2 pts)
dN1/dt = 0 (zero growth isocline of species 1, or line of equilibrium.

37c.  If the population sizes of the oaks start at values represented by the ‘X’, what will happen to the population sizes of each oak species over time? (2 pts)
They will both grow

37d.  If the population sizes of the oaks start at values represented by the dot (where the lines cross), what will happen to the sizes of their populations over time? (3 pts)
They will not change.

38.  (3 pts)  What is “asymmetric competition”? For example, what allows two different barnacles (Rock and Poli’s Stellate) to both live in the intertidal zone? (4 pts)
One species, rock barnacle, is a better competitor, in this case because of its larger size.  The other species (poli's stellate barnacle) can tolerate more stressful environments.

39. List three desirable characteristics of a species used in biocontrol. (3 pts)
1.  Adapted to the same environments as pest
2.  host-specific
3.  Abundant
-- high r
-- does not drive its prey to extinction