Question

A food web in a certain ecosystem consists of seals that feed on krill, which in turn feed on phytoplankton. Extensive krill fishing reduces the krill population rapidly. What would be observed in the ecosystem as an immediate effect of this? A) The seals would decrease in number and the phytoplankton would increase in number. B) The phytoplankton would decrease rapidly, because the seals would now feed exclusively on them. C) This would have no effect on the phytoplankton population as they just need sunlight to survive. D) The seals would increase in number because the lack of krill would mean less competition for food.

Answer 1

Answer: Option A) The seals would decrease in number and the phytoplankton would increase in number

Explanation:

The food web can be illustrated as follows: Seal --> Krill --> Phytoplankton

Where phytoplankton is the producer of food, krill is the primary consumer while seal is the secondary consumer.

So, reducing the krill population would immediately cause food shortage for seals, and lessen consumption of phytoplanktons.

Thus, the seals would decrease in number due to starvation and death, while the phytoplankton would increase in number