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.
(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
Which one of the following is not a terrestial ecosystem ?
Forest, Grassland, Aquarium, Desert
(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 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 ?
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]
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 ?
Describe how decomposers facilitate recycling of matter in order to maintain balance in the ecosystem. [Foreign]
What name has been given to those organisms which break down the complex organic compounds present in dead animals and plants ?
Name the organisms belonging to the second and the fourth trophic levels in the food chain comprising the following :
Frogs, Plants, Snakes, Hawk, Insects
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 ?
What is the functional unit of the environment comprising of the living and non-living components called ?
Why did United Nations act to control the production of chlorofluorocarbons (CFCs) used in refrigerators? [Delhi]
Which of the following belong to the same trophic level ?
Tree ; Frog ; Snake ; Grass ; Lizard
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
Name the phenomenon in which non-biodegradable chemicals get accumulated progressively at each trophic level of a food chain.
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 is ozone layer getting depleted at the higher levels of the atmosphere? [Delhi (C)]