Does the concept of carrying capacity apply to human beings? Does the planet as a whole have a human carrying capacity, or do human beings have an infinite capacity to improve life through such means as obtaining greater crop yields and becoming more energy efficient?

A(n) _________ consists of all members of a single species that live in a defined geographic region, while a(n) __________ consists of the populations of all species that live in a defined region.

a. ecosystem; community

b. ecosystem; biosphere

c. community; ecosystem

d. population; community

e. biome; ecosystem

Is human disease a form of environmental resistance?

A community and all the nonliving elements that interact with it (sunlight, nutrients, soil, etc.) is called

a. a population group.

b. a biosphere.

c. an ecosystem.

d. a biome.

e. a social system.

Some scientists argue that no single factor poses a greater threat to the environment than the continued growth of the human population, while others believe the use of resources per person is a more critical factor. What arguments can you think of for or against either proposition?

The largest scale of life, which can be thought of as the interaction of all of Earth’s ecosystems, is called

a. the biome.

b. the ecosphere.

c. the biosphere.

d. the environment zone.

e. the ionosphere.

When population growth increases in proportion to the number of members of a population, __________ growth is said to have occurred.

a. density-dependent

b. density-independent

c. K-selected

d. arithmetical

e. exponential

K-selected species tend to (select all that apply):

a. experience their environments as unstable.

b. have stable populations.

c. have their populations limited by carrying capacity.

d. provide little care to their offspring.

e. be most affected by biological forces.

r-selected species tend to (select all that apply):

a. have their populations limited by reproductive rate.

b. experience their environments as unstable.

c. provide abundant care to their offspring.

d. have populations that are strongly affected by physical forces.

e. face density-dependent pressures on their populations.

The human total fertility rate (select all that apply):

a. is the average number of children born to each family in a population.

b. has been dropping worldwide in recent decades.

c. must be at about 3 for a population to be at replacement level.

d. is generally much lower in less- developed countries.

e. is higher in the United States than in most developed countries.

The number of sperm that can fuse with an oocyte is limited to _______. This is vital in order to make sure that a fertilized egg has a balanced number of _______ from the father and the mother.