Question

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.

Short answer

1. The option “it is a rare, top-level predator” is false.
2. The option “its effective population size is lower than its total population size” is false.
3. The option “its genetic diversity is very low” is true.
4. The option “it is not well adapted to edge conditions” is false.

Step-by-step solution

Extinction vortex

Extinction vortex involves forces that act on small populations. It causes the population to enter into a vortex and undergo a further decrease in population size to a state where the population's long-term survival is threatened.

It drives a population towards the extinction path.

Explanation of option ‘(A)’

A top-level predator preys on other organisms but is not preyed upon. They occupy the highest trophic level and the top of the food chain, maintaining the ecological balance.

Thus, a rare top-level predator is not a distinguishing characteristic for extinction vortex.

Therefore, the given statement is false.

Explanation of option ‘(B)’

The effective population size is the number of individual reproducing organisms required to ensure a population's survival. Total population size is simply the number of species present in a population.

Having an effective population means having reproducing organisms to keep the population of species alive.

Thus, an effective population size lower than its total population size does not threaten species survival.

Therefore, the given statement is false.

Explanation of option ‘(C)’

Low genetic diversity is very sensitive to diseases and pathogens. Lower the genetic diversity; more is the population's risk of getting hit by an infection and lowers the chance of survival.

Thus, a low genetic diversity can push small populations into an extinction vortex.

Therefore, the given statement is true.

Explanation of option ‘(D)’

Edge conditions prevail along habitat boundaries. Fragmentation leads to more edge conditions and poses some serious problems for the population dwelling there.

However, it is not necessarily a distinguishing characteristic for extinction vortex.

Thus, edge conditions could pose problems for the population but is not a characteristic of an extinction vortex.

Therefore, the given statement is false.