Write the full form of CFC. Give its one harmful effect.
CFC – Chlorofluorocarbons. Chlorofluorocarbons released into the air react with ozone gas present in the ozone layer and destroy it gradually.
Which one of the following is not a terrestial ecosystem ?
Forest, Grassland, Aquarium, Desert
(a) What is meant by biodegradable waste materials ? Give two examples of biodegradable wastes.
(b) Which of the following materials are non-biodegradable ?
Aluminium wire, Tea leaves, Synthetic fibre, Wool
(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.
Describe how decomposers facilitate recycling of matter in order to maintain balance in the ecosystem. [Foreign]
Select two non-biodegradable substances from the following waste generated in a kitchen: spoilt food, paper bags, milk bags, vegetable peels, tin cans, used tea leaves. [Delhi]
Which of the following belong to the same trophic level ?
Tree ; Frog ; Snake ; Grass ; Lizard
Can the organisms of any trophic level be removed without causing any damage to the ecosystem ? Will the impact of removing all the organisms in a trophic level be different for different trophic levels ?
Write one or two words for each of the following statements/definitions :Write one or two words for each of the following statements/definitions :
(a) Each level of food chain where transfer of energy takes place
(b) The physical factors like temperature, rainfall, light, soil, air and water of an ecosystem
(c) Organisms which depend on the producers for food either directly or indirectly
(d) The physical and biological world where we live in
(e) Selfcontained unit of living things and their non-living environment needing only sunlight for its functioning
What name has been given to those organisms which break down the complex organic compounds present in dead animals and plants ?
What is the functional unit of the environment comprising of the living and non-living components called ?
Name the organisms belonging to the second and the fourth trophic levels in the food chain comprising the following :
Frogs, Plants, Snakes, Hawk, Insects
A student went to study a local pond. In one part of the pond she noticed tadpoles scraping at some pond weed. In another part she saw a water beetle holding a tadpole in its jaws.A student went to study a local pond. In one part of the pond she noticed tadpoles scraping at some pond weed. In another part she saw a water beetle holding a tadpole in its jaws.
(a) Construct a food chain for the pond.
(b) How many links are there in this chain ?
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 ?
Fill in the following blanks with suitable words :Fill in the following blanks with suitable words :
(a) Ultraviolet rays can cause skin…………………
(b) Pesticides enter the food chain at the…………………. level
(c) Grass →…………….→Human
(d) Lettuce →…………….→ Fox
(e) Plants→ Antelope→ …………….
Why did United Nations act to control the production of chlorofluorocarbons (CFCs) used in refrigerators? [Delhi]
Give an example to illustrate that indiscriminate use of pesticides may result-in the degradation of the environment. [All India]
State two problems caused by the non- biodegradable waste that we generate in our daily life. [All India (C)]
Name the phenomenon in which non-biodegradable chemicals get accumulated progressively at each trophic level of a food chain.
State whether the following statement is true or false :
Only 10 per cent of the light energy given by the sun is available for transfer at each higher trophic level in a food chain.
Why are bacteria and fungi called decomposers? List any two advantages of decomposers to the environment. [Delhi]