Question

As it passes into food chain, the concentration of DDT
A. Remains same
B. Decreases
C. Increases
D. Unpredictable

Answer 1

Hint: In food chains, it is seen that the level of DDT is directly proportional to the food chain progresses. Due to the high solubility of DDT in fats, it persists in the human body, it is sustained in the food chain. DDT is present in nature.

Complete answer:
- A food chain describes a linear sequence of transfer of food and matter from starting from producer organisms (such as grass or trees which use radiation from the sun to make their food) and ending at apex predator species,(like killer whales) detritivores,(like earthworm) or decomposer species (like fungi or bacteria). Each level of the food chain represents a different trophic level.
- DDT (Dichlorodiphenyltrichloroethane) is an organochlorinated compound which is stable in nature. DDT is a pesticide. DDT gets passed from one trophic level to the next trophic level. DDT level increases as the food chain progresses. It means the primary consumers will be seen and so on. The top carnivore will sustain the highest concentration of DDT. This is because the consumers at the successive trophic level fulfill the energy requirements.
- Examples of food chains
Grass – grasshopper – frog - snake - eagle.
Nectar ( flowers ) –butterflies –small birds –foxes.
Phytoplankton – zooplankton – fish – seal – the great white shark.
Microbes – shrimp –crabs.

Note:
Food chains were first introduced by the Arab scientist and philosopher. Food chains are very important for the survival of most of the species as they provide food to almost all organisms or species. When only one element is removed from the food chain it can result in the extinction of a species in some cases.