Question

Which of the following 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.

Short answer

1. The option “toxic chemicals in the environment pose greater risk to top-level predators than to primary consumers” is true.
2. The option “populations of top-level predators are generally smaller than populations of primary consumers” is false.
3. The option “the biomass of producers in an ecosystem is generally higher than the biomass of primary consumers” is false.
4. The option “only a small portion of the energy captured by producers is transferred to consumers” is false.

Step-by-step solution

Biomagnification

Biomagnification is the piling up of toxic substances in the body of organisms in higher concentrations with subsequent trophic levels. Some examples of toxic substances are heavy metals and pesticides.

Explanation of option ‘(A)’

Toxins are non-degradable and accumulate in the environment. Organisms at lower trophic levels consume toxins and pass them to organisms at the higher trophic level in higher concentrations.

Thus, the toxins pose a more significant threat to top-level predators due to their presence in greater concentrations than those present in lower trophic level organisms such as primary consumers.

Therefore, the given statement is true.

Explanation of option ‘(B)’

Biological magnification occurs as toxins accumulate in magnified concentrations in tissues of top-level predators when they feed on primary consumers.

The number of organisms at a trophic level does not influence biomagnification. It passes through the food chain and not population size.

Thus, the population size does not matter in biological magnification.

Therefore, the given statement is false.

Explanation of option ‘(C)’

Biomass of a trophic level is the amount of matter present in them. As the trophic level increases, the biomass decreases. Biomass depends on energy dissipation and production.

Thus, biomass depends on trophic levels and is not a consequence of biological magnification.

Therefore, the given statement is false.

Explanation of option ‘(D)’

As one organism from a higher trophic level feeds on another from a lower trophic level, only ten percent of energy transfer occurs to the higher trophic level. This energy transfer is irrespective of biomagnification.

Thus, energy transfer through trophic levels is not related to biological magnification.

Therefore, the given statement is false.