(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) We take a piece of paper and a plastic bag (Polythene Bag). Now dig the ground to about 15 centimeters depth and place the piece of paper and plastic bag in the dug up ground separately. After a month, we dig up the buried material and observe them. We will find that the piece of paper has been partially eaten up but the plastic bag has been remained unaffected. This means that the paper have been decomposed by the micro-organisms present in the soil. So paper is biodegradable. On the other hand, the plastic bag has not been decomposed by the micro ?organisms present in the soil, therefore It is non-biodegradable.
(b) It is due to the property of decomposer organisms of being specific in their action that some waste materials are biodegradable and other are non- biodegradable.
Name the phenomenon in which non-biodegradable chemicals get accumulated progressively at each trophic level of a food chain.
What is the functional unit of the environment comprising of the living and non-living components called ?
Which one of the following is not a terrestial ecosystem ?
Forest, Grassland, Aquarium, Desert
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 ?
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]
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
(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
What are the causes of depletion of ozone layer ? Which diseases are likely to be caused if the ozone layer will become thinner ?
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)]
State two problems caused by the non- biodegradable waste that we generate in our daily life. [All India (C)]
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 of the following belong to the first trophic level of a food chain? Grass, Grasshopper, Plants, Rat, Tiger [Foreign]
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 organisms belong to third and fourth trophic levels in the food chain comprising the following ?
Rats, Plants, Hawk, Snakes
Which one term in the following includes the others ?
air, flora, fauna, environment, water, sunlight, soil
Explain the terms ‘producer’ and ‘consumer’. Give two examples of producers and two of consumers.
(a) Define decomposers. Name one decomposer.
(b) What is the role of decomposers in the ecosystem ?
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 ?
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
Give a method for the disposal of household wastes such as left-over food, fruit and vegetable peels, and leaves of potted plants.