Ecology Unit

Which of the following best defines an ecosystem?

• a group of species living in a given area

• all of the living and nonliving factors in an environment

• all of the species living in a given area

• the regions on Earth that can support life

Which of the following is an abiotic factor?

• wind

• mushroom

• honey bee

• pollen

Which ecological level consists of a group of one species living in a given area?

• a biosphere

• a community

• a population

• an ecosystem

Which of the following is an abiotic factor?

• temperature

• mold

• pine tree

• wolf

A population of squirrels eats acorns from local oak trees. In some years, oak trees produce much greater numbers of acorns than usual. Which of the following is the most direct effect of an increase of acorns on the squirrel population?

• the population size increases

• the population expands its territory into new habitats

• the population size decreases due to competition

• the population has fewer predators

Which of the following factors can be representative of a population near carrying capacity?

• an increase in younger population members

• an increase in resource competition

• an increased ratio of birth rate to death rate

• an increase in offspring survival rate

An isolated bird population on a remote island remains at a relatively constant size year after year. Which of the following most likely describes the birthrate and death rate for the population?

• Birthrate and death rate are both zero

• Birthrate is significantly lower than death rate

• Birthrate is significantly greater than death rate

• Birthrate and death rate are closer to equal

Which of the following statements correctly describes the full value of a keystone species on its ecological community?

• they are superior predators that displace inferior competitors

• the are non-native organisms that can damage the ecosystem, so removing them increases biodiversity

• they have a disproportionate effect relative to their frequency in the population, so the ecosystem often collapses whey they are removed

• they are the largest species in a community and consume more than the others

A volcanic eruption makes a local island completely devoid of life. Over the next few years, some small lichens (very small plants) began to colonize the remaining rock and soil. This is an example of which of the following?

• climax community

• secondary succession

• natural selection

• primary succession

A seal and a shark eat the same kind of fish. What ecological interaction describes the relationship between them?

• competition

• predation

• commensalism

• mutualism