31) A biologist is studying the population dynamics of pocket gophers in a meadow in central Oregon. She noted that, when population numbers are high, death rates from disease and starvation increase. This is an example of:

A) r-selected growth.

B) the principle of intrinsic rate of growth.

C) exponential growth.

D) density dependent control.

32) Which of the following items can be classified as a density independent factor in population growth?

A) food supply

B) disease

C) temperature

D) drinking water supply

33) Which of the following would be generally true of r-selected species?

A) Most live until older age.

B) All live very short life spans.

C) R-selected species are larger organisms that produce few offspring.

D) R-selected species are smaller organisms that produce many offspring.

34) You are doing field study work with a scientist studying spiders in the Amazon rainforest. You come across a previously undiscovered species of spider and set up a video camera with a zoom lens to observe it closely without disturbing it. You see the female spider lay two eggs, kill an ant that tried to eat one of the eggs, and preserve the ant to feed the hatchlings the next day. She lays two more eggs as soon as the two offspring grow larger and leave. When your mentor asks for a monthly update, what exciting news do you have for her about this species?

A) It exhibits unusual r-selected tendencies.

B) It exhibits unusual K-selected tendencies.

C) It exhibits unusual intelligent learning tendencies.

D) It exhibits unusual zero population growth tendencies.

35) From the time of the industrial revolution until about 50 years ago, the human population growth rate most closely resembles:

A) linear growth.

B) exponential growth.

C) variable, unpredictable growth.

D) fluctuating increases and decreases, with overall slow growth.

36) A population with a fertility rate of 2.1 will:

A) slowly shrink.

B) slowly grow.

C) double each generation.

D) decrease by half each generation.

E) exhibit zero population growth.

37) What would be a reasonable conclusion about a country with a fertility rate of about 1.6?

A) The population will grow at a yearly rate of 1.6 percent.

B) The population is likely to shrink.

C) Zero population growth will occur.

D) It must be a relatively young population.

38) What would be logical to conclude about a country with a population pyramid having a disproportionately large number of individuals in the 15—44 year old range?

A) The country is a developed country.

B) The country will exhibit little population growth.

C) The country will exhibit large population growth.

D) The country will exhibit zero population growth.

39) Which is true of predictions about the expected population of the United States in the year 2050?

A) The U.S. population will exceed 1.5 billion.

B) Immigration is not expected to have a large effect on the U.S. population.

C) The population is expected to grow about 43 percent.

D) Emigration is expected to have a large effect on the U.S. population.

40) Ecologists often say that one individual living in a developed country cannot be counted as ecologically equal to one individual from a developing country because:

A) the fertility rates are the same.

B) the use of natural resources per person is different.

C) r is different.

D) K is different.

41) A country’s fertility rate suggests zero population growth, but it shows an increase of 20—30 percent over 50 years. What might account for this?

A) better food availability

B) a larger proportion of post-reproductive females

C) higher environmental resistance

D) lower logistic growth

E) immigration