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प्रश्न
'If we excessively use pesticides to protect the crops from diseases, then it may cause long-term damage to mankind'. Justify this statement.
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उत्तर
Chemical substances such as pesticides are sprayed over crop plants to protect them from pests and diseases. When herbivorous animals eat the plant food, these poisonous chemical pesticides go into their bodies. Man, being an omnivore, eats plant food as well as the meat of herbivores. Thus, the pesticides present in plant food and herbivores get transferred to man's body through food. Pesticides are non-biodegradable chemicals, so they get accumulated at each trophic level. Since humans occupy the top level in any food chain, the maximum amount of harmful chemical pesticides gets accumulated in our bodies, damaging our health gradually.
Hence the statement 'excessive use of pesticides to protect crops from diseases may cause long-term damage to mankind' is justified.
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संबंधित प्रश्न
The first trophic level in a food chain is always a green plant. Why ?
The following statement is true or false :
In biology, human beings are called producers.
What is meant by a primary consumer, secondary consumer and a tertiary consumer? Give one example of each.
What will happen if we kill all the organisms in one trophic level?
Write down a food chain in the sea.
Which of the following are decomposers of dead organisms?
| Bacteria | Fungi | Viruses |
| (a) no | yes | yes |
| (b) yes | no | yes |
| (c) yes | yes | no |
| (d) yes | yes | yes |
One of the following is not a consumer. This one is :
(a) giraffe
(b) antelope
(c) algae
(d) alligator
The sea water contains water beetles, tadpole, fish and weeds.
Which organisms can trap solar energy to make food?
A food chain occurring in the sea which provides food for many people can be written as :
phytoplankton → zooplankton → X → Y
What could be X?
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What is ten per cent law? Explain with an example.
What percentage of sun's energy falling on the leaves of green plants is utilised by the plants in the process of photosynthesis and stored as chemical energy of food?
(a) 99 per cent
(b) 10 per cent
(c) 1 per cent
(d) 20 per cent
The surface of water in a lake appears green due to a layer of tiny free-floating organisms X on its surface. The lake water also contains organisms like water beetle, fish and tadpole. The sun shines over the lake water and provides energy for the functioning of this lake ecosystem.
(a) What could organisms X be?
(b) Write a food chain comprising of all the four organisms mentioned.
(c) What is the general name of the food chains like the one written above?
(d) Name (i) secondary consumer (ii) producer (iii) tertiary consumer, and (iv) primary consumer, in the above food chain.
(e) If the tertiary consumer gets 0.2 J of energy from the secondary consumer, then how much energy was radiated by the sun to the producer?
What are decomposers? What will be the consequence if the decomposers are completely eradicated from an ecosystem? Give justification in support of your answer.
Give some examples for Biodegradable and Non-biodegradable waste.
| S. No. | Biodegradable waste | Non-biodegradable waste |
| 1. | Food Waste | Plastic Bottles |
| 2. | ||
| 3. | ||
| 4. | ||
| 5. |
Food chains are very important for the survival of most species.
Matter and energy are two fundamental inputs of an ecosystem. Movement of:
Observe the food web and answer the questions given below:
Why do all food chains start with plants?
The food chain begins with the energy given by the ______.
What are autotrophs?
What will happen if deer is missing in the food chain given below?
Grass → Deer → Tiger
