Biology Test Biology Ecology & Environmental Interactions 2

Question 1

Which of the following best describes a keystone species?

Accepted Answer

A species whose removal causes dramatic ecosystem change disproportionate to its abundance

Answer

A species with the largest population in an ecosystem

Answer

A species at the top of the food chain

Answer

A species that produces the most biomass

Question 2

In a food web, secondary consumers are organisms that

Accepted Answer

Eat primary consumers

Answer

Produce energy through photosynthesis

Answer

Eat only plants

Answer

Decompose dead organic matter

Question 3

The nitrogen cycle is critical to ecosystems primarily because nitrogen is

Accepted Answer

An essential component of amino acids and nucleic acids

Answer

A greenhouse gas that traps heat

Answer

Required for photosynthesis as an electron donor

Answer

The primary source of energy for decomposers

Question 4

Which term describes the gradual process by which a bare rock surface develops into a mature forest community?

Accepted Answer

Primary succession

Answer

Secondary succession

Answer

Ecological regression

Answer

Eutrophication

Question 5

An organism that benefits from a relationship while its host is neither helped nor harmed is engaged in

Accepted Answer

Commensalism

Answer

Mutualism

Answer

Predation

Answer

Parasitism

Question 6

What happens to energy as it moves from one trophic level to the next in an ecosystem?

Accepted Answer

About 90% is lost, primarily as heat

Answer

It doubles due to metabolic processes

Answer

It is fully conserved and transferred completely

Answer

It increases because higher trophic organisms are more efficient

Question 7

Which biome is characterized by permafrost, extremely low temperatures, and low biodiversity dominated by mosses and lichens?

Accepted Answer

Tundra

Answer

Taiga (boreal forest)

Answer

Temperate grassland

Answer

Chaparral