Biology: Ecology

Which phrase best describes biodiversity?

• the number of individuals in an ecosystem

• the amount of biomass in an ecosystem

• the amount of available energy in an ecosystem

• the number of species in an ecosystem

The close living association and interaction between two species of organisms, regardless of the nature of the relationship, is known as

• Commensalism

• mutualism

• symbiosis

• competition

A population of lions live on a grassland in Africa. A population of zebra and a population of gazelle also live there. Together, these populations interact with one another. Which of these is the best description of a group of populations interacting together?

• ecosystem biome

• biome

• community

• cladosphere

An organism that has an unusually large effect on an ecosystem is called a(n)

• keystone species

• omnivore

• biotic factor

• heterotroph

Zebras live on the savannas of Africa. A watering hole on the savanna would be a part of a zebra's

• niche

• biotic factor

• abiotic factor

• habitat

Which of the following is a density-dependent limiting factor?

• unusual weather

• length of winter

• human activities

• competition

Which of the following will increase the size of a population?

• emigrantion and deaths

• immigration and deaths

• emigration and births

• immigration and births

Pioneer species are the first

• trees to grow in an area that has been disturbed

• trees that replace the original trees after a forest fire

• organisms to live in previously uninhabited areas.

• organisms to live in previously inhabited areas.

Which process is part of the hydrologic cycle?

• nitrification

• evaporation

• decomposition

• ammonification

Which organisms help convert gaseous nitrogen into ammonia in the nitrogen cycle?

• bacteria

• trees

• squirrels

• grasses