Biology Test Biology Ecology & Environmental Interactions 3

Question 1

Eutrophication of a lake is most directly caused by

Accepted Answer

Excess nutrient runoff stimulating algal blooms

Answer

Excess nitrogen and phosphorus from agricultural runoff cause algal blooms; when algae die, decomposition depletes oxygen, creating dead zones.

Question 2

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

Accepted Answer

Disease spreading more rapidly in a crowded population

Answer

Density-dependent factors like disease, predation, and competition intensify as population density increases.

Question 3

In an ecological pyramid of biomass, which level always has the greatest biomass?

Accepted Answer

Producers

Answer

Producers (plants) form the base of the biomass pyramid because energy and mass decrease at each successive trophic level.

Question 4

Which relationship exists between clownfish and sea anemones, where both organisms benefit?

Accepted Answer

Mutualism

Answer

Clownfish gain protection from the anemone's stinging tentacles, while the fish's movement aerates the anemone and removes parasites — a mutualistic relationship.

Question 5

The reintroduction of wolves to Yellowstone National Park caused changes that eventually led to stabilization of riverbanks through a process called

Accepted Answer

A trophic cascade

Answer

Wolves reduced elk overgrazing of vegetation near rivers, allowing plants to regrow and stabilize banks — a classic trophic cascade effect.

Biology Practice Test

Biology Practice Test

Biology Test Biology Ecology & Environmental Interactions 3