Why are bacteria and fungi called decomposers? List any two advantages of decomposers to the environment. [Delhi]
Bacteria and fungi breakdown the dead remains and waste products of organisms. These micro organisms are called the decomposers as they breakdown the complex organic substances into simple inorganic substances that go into the soil and are used up once more by the plants.
Two advantages of decomposers to the environment are as follows:
Name the phenomenon in which non-biodegradable chemicals get accumulated progressively at each trophic level of a food chain.
(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
What is the functional unit of the environment comprising of the living and non-living components called ?
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.
Which one term in the following includes the others ?
air, flora, fauna, environment, water, sunlight, soil
(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.
At which trophic level a person is feeding when he is eating :At which trophic level a person is feeding when he is eating :
(a) roasted chicken
(b) bread
(c) eggs
(d) apple
(e) fish
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 ?
Describe how decomposers facilitate recycling of matter in order to maintain balance in the ecosystem. [Foreign]
Give an example to illustrate that indiscriminate use of pesticides may result-in the degradation of the environment. [All India]
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
(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.
‘If we excessively use pesticides to protect the crops from diseases, then it may cause long-term damage to mankind’. Justify this statement.
Which disease is caused in human beings due to depletion of ozone layer in the atmosphere? [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]
What name has been given to those organisms which break down the complex organic compounds present in dead animals and plants ?
Which of the following belong to the same trophic level ?
Goat; Spider ; Plants ; Hawk ; Rat .
What is the difference between the food habits of organisms belonging to the first and the third trophic levels ? Give one example each of the organisms belonging to these two trophic levels.
“Damage to the ozone layer is a cause for concern.” Justify this statement. Suggest any two steps to limit this damage. ‘ [Delhi]
Why did United Nations act to control the production of chlorofluorocarbons (CFCs) used in refrigerators? [Delhi]
What is meant by a primary consumer, secondary consumer and a tertiary consumer ? Give one example of each.
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→ …………….
State two problems caused by the non- biodegradable waste that we generate in our daily life. [All India (C)]