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प्रश्न
What are trophic levels? Give an example of a food chain and state the different trophic levels in it.
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उत्तर १
The various links or steps in a food chain at which the transfer of food and energy takes place are called trophic levels.
The producers form the first trophic level as they manufacture food. The primary consumers form the second trophic level, the secondary consumers form the third, and the tertiary consumers form the fourth trophic level.
In the above fig. The grass is the producer, which is eaten by the grasshopper, known as the primary consumer. Then the grasshopper is eaten by a shrew, a secondary consumer, and lastly shrew is eaten up by an owl, a tertiary consumer.
उत्तर २
The various steps in food chain at which transfer of food energy takes place are called trophic levels.
Example: Food chain operating in a grassland.
Grass → Insects → Frogs → Snakes
- Grass → 1 st trophic level
- Insects → 2 nd trophic level
- Frogs → 3 rd trophic level
- Birds → 4 th trophic level
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संबंधित प्रश्न
Which of the following are always at the second tropic level of food chains?
Give reason to justify the following: The existence of decomposers is essential in a biosphere.
List two important roles play in the environment by decomposers.
Which of the following constitute a food-chain?
What will happen if we kill all the organisms in one trophic level?
Explain how the pesticides enter a food chain and subsequently get into our body.
What name has been given to those organisms which break down the complex organic compounds present in dead animals and plants?
Name one decomposer.
Consider the food chain :
Grass → Deer → Lion
What will happen if all the lions are removed from the above food chain?
What will happen if deer is missing in the food chain given below?
Grass → Deer → Tiger
In the food chain comprising of a snake, grass, insect, and frog, the secondary consumer is :
(a) insect
(b) snake
(c) frog
(d) grass
A food chain occurring in the sea which provides food for many people can be written as :
phytoplankton → zooplankton → X → Y
Name two zooplanktons.
How much energy will be available to hawks in the food chain comprising hawk, snake, paddy and mice, if 10,000 J of energy is available to paddy from the sun?
Which of the following limits the number of trophic levels in a food chain?
(a) insufficient food supply from producer level
(b) decrease in energy at higher trophic levels
(c) increase in the number of organisms at higher trophic levels
(d) accumulation of harmful chemicals at higher trophic levels
Your mother always thought that fruit juices are very healthy for everyone. One day she read in the newspaper that some brands of fruit juices in the market have been found to contain certain level of pesticides in them. She got worried as pesticides are injurious to our health.
(a) How would you explain to your mother about fruit juices getting contaminated with pesticides?
(b) It is said that when these harmful pesticides enter our body as well as in the bodies of other organisms they get accumulated and beyond a limit cause harm and damage to our organs. Name the phenomenon and write about it.
Arrange the following in a correct sequence and form a food chain
Rabbit → Carrot → Eagle → Snake
Write the importance of the food chain.
If 100 J energy is available at the producer level in a food chain then the energy available to the secondary consumer will be ______.
Each level in the food chain is called a ______ level.
Use of several pesticides which results in excessive accumulation of pesticides in rivers of ponds, is a matter of deep concern. Justify this statement.
