Explain ‘biological magnification’ with the help of an example. [All India]
Pesticides used in crops are washed down .into the soil. From soil these are absorbed by plants along with water and minerals and thus, they enter the food chain. While consuming the crops, human beings also consume these pesticides which get accumulated in our bodies. This phenomenon is known as biological magnification.
Name the phenomenon in which non-biodegradable chemicals get accumulated progressively at each trophic level of a food chain.
What is the functional unit of the environment comprising of the living and non-living components called ?
Which one of the following is not a terrestial ecosystem ?
Forest, Grassland, Aquarium, Desert
If a harmful chemical enters a food chain comprising cat, mice and plants, which one of these organisms is likely to have the maximum concentration of the harmful chemical in its body ?
Why is ozone layer getting depleted at the higher levels of the atmosphere? [Delhi (C)]
(a) Define decomposers. Name one decomposer.
(b) What is the role of decomposers in the ecosystem ?
The number of malaria patients in a village increased tremendously when large number of frogs were exported from the village. What could be the cause for it ?
Give a method for the disposal of household wastes such as left-over food, fruit and vegetable peels, and leaves of potted plants.
(a) Describe an activity to show that while paper is biodegradable but plastic (say, polythene) is non-
biodegradable.
(b) Explain why, some materials are biodegradable but some are non-biodegradable.
(a) What is meant by non-biodegradable waste materials ? Give two examples of non-biodegradable wastes.
(b) Which of the following materials are biodegradable ?Animal bones, Iron nails, Plastic mugs, Leather belts, Silver foil
(a) Define an ecosystem. Give examples of any two ecosystems.
(b) List the biotic and abiotic components of an ecosystem.
Explain how, harmful ultraviolet radiations of sunlight are prevented from reaching the earth’s surface.
‘If we excessively use pesticides to protect the crops from diseases, then it may cause long-term damage to mankind’. Justify this statement.
Why are bacteria and fungi called decomposers? List any two advantages of decomposers to the environment. [Delhi]
Which of the following belong to the same trophic level ?
Tree ; Frog ; Snake ; Grass ; Lizard
Which disease is caused in human beings due to depletion of ozone layer in the atmosphere? [Foreign]
“Damage to the ozone layer is a cause for concern.” Justify this statement. Suggest any two steps to limit this damage. ‘ [Delhi]