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.
Give a method for the disposal of household wastes such as left-over food, fruit and vegetable peels, and leaves of potted plants.
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 ?
What name has been given to those organisms which break down the complex organic compounds present in dead animals and plants ?
Describe how decomposers facilitate recycling of matter in order to maintain balance in the ecosystem. [Foreign]
What is the functional unit of the environment comprising of the living and non-living components called ?
(a) Define decomposers. Name one decomposer.
(b) What is the role of decomposers in the ecosystem ?
“Damage to the ozone layer is a cause for concern.” Justify this statement. Suggest any two steps to limit this damage. ‘ [Delhi]
‘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 phenomenon in which non-biodegradable chemicals get accumulated progressively at each trophic level of a food chain.
Which of the following belong to the same trophic level ?
Goat; Spider ; Plants ; Hawk ; Rat .
What are the causes of depletion of ozone layer ? Which diseases are likely to be caused if the ozone layer will become thinner ?
State two problems caused by the non- biodegradable waste that we generate in our daily life. [All India (C)]
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]
Explain the terms ‘producer’ and ‘consumer’. Give two examples of producers and two of consumers.
(a) With the help of a flow diagram, describe how energy from the sun flows through various trophic levels.
(b) Explain why, the flow of energy in the ecosystem is said to be unidirectional.
Consider the food chain :
Grass → Deer → Lion
What will happen if all the lions are removed from the above food 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→ …………….
What is meant by bioconcentration of pesticides ? Which common pesticide has accumulated in human body in considerable amounts ?
Why are bacteria and fungi called decomposers? List any two advantages of decomposers to the environment. [Delhi]
Which disease is caused in human beings due to depletion of ozone layer in the atmosphere? [Foreign]
How is ozone formed in the upper atmosphere? Why is the damage of ozone layer a cause of concern to us? State a cause of this damage. [Delhi(C)]
Give an example to illustrate that indiscriminate use of pesticides may result-in the degradation of the environment. [All India]
In a food chain, 10,000 joules of energy is available to the producer. How much energy will be available to the secondary consumer to transfer it to the tertiary consumer? [All India ]
Which one of the following is not a terrestial ecosystem ?
Forest, Grassland, Aquarium, Desert
Which of the following belong to the same trophic level ?
Tree ; Frog ; Snake ; Grass ; Lizard