What is biological magnification? Explain how it happens with the help of a food chain.
How to lay out the answer. Follow the frame, then write it in your own words.
1 · Define. Biological magnification is the increase in the concentration of harmful non-biodegradable chemicals at each higher trophic level.
2 · Show the path. [Food chain: pond water → phytoplankton → zooplankton → small fish → big fish → human, with the pesticide level rising at each step]
3 · Explain why.
Pesticides wash into soil and water and enter plants.
They are not broken down or removed from the body.
Each eater eats many organisms from the level below.
4 · Real life. Pesticide from fields can reach people through fish and vegetables.
5 · Close in one line. So the top consumers, often humans, get the largest dose.
Scoring tip: Use the words 'non-biodegradable' and 'increases at each trophic level'. Name one pesticide.
