CLEP Biology Ecology & Evolutionary Processes 4

Question 1

Which type of selection favors individuals at both extremes of a phenotypic trait and eliminates intermediate phenotypes?

Accepted Answer

Disruptive selection

Answer

Disruptive (diversifying) selection favors phenotypic extremes over intermediate forms, potentially splitting a population into two distinct groups.

Question 2

A keystone species is best described as a species that:

Accepted Answer

Has a disproportionately large effect on its ecosystem relative to its biomass

Answer

A keystone species has an outsized ecological impact — its removal causes dramatic changes in community structure, far greater than expected from its numbers alone.

Question 3

Which reproductive isolating mechanism prevents two species from mating because they breed at different times of year?

Accepted Answer

Temporal isolation

Answer

Temporal isolation is a prezygotic barrier where species breed at different times (seasons, times of day), preventing interbreeding even if they share the same habitat.

Question 4

The r-selected reproductive strategy is characterized by:

Accepted Answer

Many offspring with little parental investment

Answer

r-selected species (r-strategists) produce large numbers of offspring with minimal parental care, maximizing reproductive rate rather than offspring survival.

Question 5

Carbon is returned from the biotic community to the atmosphere primarily through:

Accepted Answer

Cellular respiration and decomposition

Answer

Cellular respiration by all organisms and decomposition by decomposers release CO₂ back into the atmosphere, completing the carbon cycle.

CLEP Practice Test

CLEP Practice Test

CLEP Biology Ecology & Evolutionary Processes 4