Question

Use of pesticides to protect our crops affect organisms at various trophic levels especially human beings. Name the phenomenon involved and explain how does it happen.

Answer 1

Phenomenon involved: Biological magnification (also called biomagnification)

Explanation:
Biological magnification is the process by which the concentration of harmful substances such as pesticides increases as they move up through the food chain.

How it happens:
1. When pesticides are sprayed on crops, some of them get washed into the soil and water bodies.
2. These chemicals are absorbed by plants and aquatic organisms like algae.
3. Small herbivores or fish that eat these plants accumulate small amounts of pesticides in their bodies.
4. Carnivores that eat these herbivores accumulate larger amounts, because the pesticide is not broken down easily.
5. As we move to higher trophic levels, the concentration of pesticides becomes higher.
6. Humans, being at the top of the food chain, receive the highest concentration of these toxic substances.

Result:
This can lead to harmful health effects in humans such as nervous system disorders, hormonal imbalances, reproductive issues, and even cancer.

Final Answer:
Biological magnification is the phenomenon, and it occurs when toxic substances like pesticides increase in concentration at each successive trophic level, ultimately affecting humans the most.