Question 1. What is a food chain?
Answer: The food chain in nature is formed by various animals; one animal eats another animal and in turn is eaten by another animal. In this way nutrients and energy pass through one organism to another.
Activity 2
Observe carefully the organisms present around you and make a food chain on the basis of their relations of eating others and being eaten up.
Answer:
1. Cereals → Mouses → owl
2. grass → Rabbit → Wolf → lion
3 grass → insects → frog → snake → vulture
What will happen to other organisms of food chain if one organism in a food chain disappears? Discuss in the class and write in the space given below :
Answer: Consider a food chain consisting of grass, insects, frogs, snake and vultures. Suppose due to some reason all snakes got extinct. Then what will be the food of vultures ? This way all the vultures will die soon due to non- availability of food. Now there will be no animal which will eat frog. Population of frogs will increase, they will eat all the insects and then nothing remains for the frogs, ultimately frogs will die.
Question 2. What is food web?
Answer: When a number of food chains get linked with each other they form a food web.
Activity 5
Take a potted plant. Place a cardboard box with a hole on one side of the box. Note down the changes you observe in the plant after a few days.
Answer: Plant bends towards light , therefore plant will bend towards hole.
Question 3. Fill in the blanks:
(decayed, carbon dioxide, food-web, Green, Sun, Pitcher plant. Sundew plant, food chain.)
(a) In a food-web one organism can eat many other organisms.
(b) In a food chain one organism eats only one organism.
(c) Green plants prepare their food in presence of sun light.
(d) Plants absorb carbon dioxide gas from the air.
(e) Sundew and Pitcher plant are insectivorous plants.
(f) Mushrooms get their food from decayed materials.
Question 4.
Tick (✓) the right and cross (✗) the wrong sentences a:
(a) Many food chains get interlinked to form a food web. (✓)
(b) Leaves look green due to a pigment called chlorophyll. (✓)
(c) Plants produce glucose in the form of food.(✓)
(d) Plants pollute the environment. (×)
(e) The leaves of Sundew Plant look like Sun.
(✓)
Question 5. What is Photosynthesis?
Answer: Plants prepare their food in the presence of sunlight by taking carbon dioxide from air and absorbing water and minerals from soil. This process is called Photosynthesis.
Question 6. How does the Pitcher Plant meet its requirements of Nitrogen and Phosphorus?
Answer: Pitcher plant eats insects. Digestive juices of the plant extract nitrogen and phosphorus from the insects.
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