Why did United Nations act to control the production of chlorofluorocarbons (CFCs) used in refrigerators? [Delhi]
CFCs deplete the ozone layer around the earth, hence their production is controlled by United Nations.
Which one of the following is not a terrestial ecosystem ?
Forest, Grassland, Aquarium, Desert
State whether the following statements are true or false :State whether the following statements are true or false :
(a) In biology, human beings are called producers.
(b) Secondary consumers and tertiary consumers, both are carnivores.
(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
Name the phenomenon in which non-biodegradable chemicals get accumulated progressively at each trophic level of a food chain.
Which of the following are biodegradable and which non-biodegradable ?
Glass bottle, Paper, Ball point pen refill, Hay, DDT, Wheat, Cake, Wood,
Polythene bag, Jute bag, Cotton cloth, Grass, Vegetable peels
Fill in the following blanks with suitable words : Fill in the following blanks with suitable words :
(a) Decomposer organisms are……………. in their action.
(b) In nature, all green plants are……………. whereas animals are consumers.
(c) A series of organisms, each of which feeds on the next organism, the beginning of which is a green plant, is called a…………….
(d) The science that deals with the inter-relationships of living things with one another and their environment is called …………….
(e) Plastic is a……………. material whereas paper is a……………. material.
(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.
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 is ozone layer getting depleted at the higher levels of the atmosphere? [Delhi (C)]
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 ?
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
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.
Name the wastes which are generated in your house daily. What measures would you take for their disposal?
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]
Name the organisms belonging to the second and the fourth trophic levels in the food chain comprising the following :
Frogs, Plants, Snakes, Hawk, Insects
What is meant by a primary consumer, secondary consumer and a tertiary consumer ? Give one example of each.
How does a biodegradable waste differ from a non-biodegradable waste ? Give two examples of non- biodegradable wastes which pollute our environment.
(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.
(a) What is meant by ‘environment’ ?
(b) What type of substances are the major pollutants of the environment ? Name two such substances.
(c) Name the organisms whose uncontrolled activities are damaging the environment.
(d) Explain why, it is better to use paper bags than plastic bags.