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1. 1-f; 2-d; 3-e; 4-a; 5-c; 6-b
2. A species with a Type III survivorship curve would need to produce a large number of offspring because most will die off very early in life. Plants, insects, and heavily preyed-upon mammals exhibit a Type III survivorship curve.
3. 
The logistic curve is more realistic because the initial exponential growth is unsustainable. Resources will eventually become limited and population growth will slow and reach the carrying capacity.
4. Mutualism, because both the leafhopper and the bacteria benefit from the arrangement.
5. A population with a low death rate and a high birthrate would experience an overall increase in the population numbers. This population would most likely have an age structure with mostly young individuals.
6. 
Large mammals exhibit the Type I survivorship curve. The probability of survival remains high throughout their lives (which is good, considering the relatively few offspring produced), and most die after they reach old age.
7.
a. A viral disease (DD)
b. Competition for mates (DD)
c. Volcanic eruption (DI)
d. Predation (DD)
e. Wildfire (DI)
f. Oil tanker spill in ocean (DI)
g. Clearcutting forest (DI)
8. To be commensalism, the louse must benefit, and the fish must be neither harmed nor helped. If the louse perfectly replaces the function of the fish’s tongue (and no harm comes to the fish), it would be a commensal relationship.
9. c. If there is a decrease in limiting factors, this would release a restriction on growth, and the population would increase.