One characteristic that distinguishes a population in an extinction vortex from most other populations is that
a. It is a rare, top-level predator
b. Its effective population size is lower than its total population size
c. Its genetic diversity is very low
d. It is not well adapted to edge conditions

The main cause of the increase in the amount of CO₂ in Earth’s atmosphere over the past 170 years is

a. Increased worldwide primary production

b. Increased worldwide fertilizer production

c. Increased infrared radiation absorption by the atmosphere

d. The burning of fossil fuels and deforestation

Which of these is a consequence of biological magnification?

a. Toxic chemicals in the environment pose greater risk to top-level predators than to primary consumers.

b. Populations of top-level predators are generally smaller than populations of primary consumers.

c. The biomass of producers in an ecosystem is generally higher than the biomass of primary consumers.

d. Only a small portion of the energy captured by producers is transferred to consumers.

What is the single greatest threat to biodiversity?

a. Overharvesting of commercially important species

b. Habitat alteration, fragmentation, and destruction

c. Introduced species that compete with native species

d. Novel pathogens