APES Chapter 7, 8, and 9 Essay Test Fall 2011
a. Explain the difference between biotic potential and carrying capacity in the growth of a population.
b. Aside from irregular, describe the three other types of variations in population size.
c. List four environmental resistances that can affect/determine the carrying capacity of a population, two of
which should be identified as biotic and two should be abiotic, and two should be identified as density
dependent and two density independent (there will be overlaps with biotic vs. abiotic). Provide a description of
each of the four factors and how they affect/determine carrying capacity.
d. On a population growth curve (population # vs. time), when do r-selected and K-selected species experience
the most environmental pressure and why? How is this selection represented in a survivorship curve for each
species? Indentify five other differences typically seen between r-selected and K-selected species.
e. Provide two examples of how an animal population (other than humans) can increase its carrying capacity. If
the population can’t increase its carrying capacity, describe two other effects that the population will undergo
when it grows past carrying capacity.
a. Provide and explain three examples of how humans have increased the carrying capacity of their
environments in the past.
b. Do you think humans have reached their biological carrying capacity on earth? Do you think humans have
reached their cultural carrying capacity on earth? Explain your reasoning for each applying concepts learned in
c. Whether we have or have not reached our carrying capacity yet, can we still extend our carrying capacity
further? Explain your reasoning (if so, why/how; if not, why not?)
3. Explain how populations and population dynamics differ between a developed and a developing country. Be
sure to describe each of the following concepts:
a. Age structure
b. Current population growth/decline
c. At least two factors affecting birth rates for each country
d. At least two factors affecting death rates for each country
e. Rates of immigration/emigration and factors affecting them
4. There are many reasons why developing countries have much higher crude birth rates than crude death rates
over developed countries, resulting in the populations of developing countries to continually increase and
developed countries having relatively stable population sizes. Pick 3 current issues/ideas (could be social,
economical, strictly environmental… think about the “Population Bomb” video), explain each issue/idea, and
describe and how it affects the overall growth of a developed and a developing country.
a. Why are invasive species so destructive to communities?
b. Describe the three main roles that a species can have in a community. Provide one example of a species
fulfilling each role and explain how it fulfills that role.
c. Describe the five different kinds of interactions between species that exist in communities.
d. Why is biodiversity considered so important in community ecology? What are three possible effects on an
ecosystem if there is a reduction in biodiversity?