Question

1. explain how / why ddt concentrations increase as you go higher up the food chain. create an illustration to help explain.

Explanation:

DDT is a persistent organic pollutant. It is lipophilic (fat - loving) and not easily metabolized or excreted by organisms. When a primary producer (e.g., phytoplankton) takes up a small amount of DDT from the environment (e.g., water or soil), a primary consumer (e.g., small fish) that eats many of these primary producers will accumulate the DDT in its body. As we move up the food chain, a secondary consumer (e.g., large fish) that eats many primary consumers will have an even higher concentration of DDT because it is consuming the DDT stored in the bodies of multiple primary consumers. This is known as biomagnification.

For the illustration:

• At the bottom of the food chain (e.g., phytoplankton level), represent a small dot of DDT per organism.
• For the next level (small fish), show that each small fish has, say, 10 times the DDT of a phytoplankton (because it eats 10 phytoplankton).
• For the large fish (higher - level consumer), show that it has 10 times the DDT of a small fish (because it eats 10 small fish).

Answer:

DDT concentrations increase up the food chain due to biomagnification. Organisms at each trophic level consume many organisms from the lower level, accumulating the lipophilic and non - easily - excreted DDT. An illustration can show increasing DDT amounts at each successive trophic level (e.g., phytoplankton → small fish → large fish).