The number of malaria patients in a village increased tremendously when large number of frogs were exported from the village. What could be the cause for it ?
Frogs eat up mosquitoes. In the absence of frogs, the number of mosquitoes increase too much and spread malaria.
Describe how decomposers facilitate recycling of matter in order to maintain balance in the ecosystem. [Foreign]
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
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→ …………….
Name the wastes which are generated in your house daily. What measures would you take for their disposal?
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 ?
“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.
(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
In a food chain consisting of grass, frog, bird and insects, where will the concentration of the harmful chemicals be maximum ?
State two problems caused by the non- biodegradable waste that we generate in our daily life. [All India (C)]
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) Define an ecosystem. Give examples of any two ecosystems.
(b) List the biotic and abiotic components of an ecosystem.
Why did United Nations act to control the production of chlorofluorocarbons (CFCs) used in refrigerators? [Delhi]
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 of the following belong to the same trophic level ?
Tree ; Frog ; Snake ; Grass ; Lizard
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.
Explain how, harmful ultraviolet radiations of sunlight are prevented from reaching the earth’s surface.