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प्रश्न
What is a 'food web'? Show its formation.
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उत्तर
The inter-connected food chains operating in an ecosystem that establish a network of relationships among various species comprise a food web.
A food web is formed by many food chains operating together. A food web operating in a grassland is shown in the figure.
Five food chains are possible in this food web, which are as follows.
1) Grass→ Grasshopper→ Frog→ Hawk
2) Grass→Grasshopper→ Rat→ Fox
3) Grass→ Rabbit→ Fox
4) Grass→ Rat → Snake→Hawk
5) Grass→Rat →Hawk
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संबंधित प्रश्न
"Our food grains such as wheat and rice, the vegetables and fruits and even meat are found to contain varying amounts of pesticide residues." State the reason to explain how and why it happens?
Which organisms belong to third and fourth trophic levels in the food chain comprising the following?
Rats, Plants, Hawk, Snakes
Define decomposers.
Write down a food chain with five links in it.
Construct a long food chain.
Give one example of a simple food chain.
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 |
What would happen to the number of rabbits and grass plants if the number of foxes decreased?
Which common pesticide has accumulated in human body in considerable amounts?
Consider the following food chain
(i) Plants → Mice → Snakes → Hawks
(ii) Plants → Mice →Hawks
If energy available at the producer level in both the food chains is 100 J, in which case will hawks get more energy as food and by how much? Justify your answer.:
If the energy available at the producer level in a food chain is 150 J, how much energy will be transferred to : tertiary consumer?
(a) 15 J
(b) 10 J
(c) 1.50 J
(d) 0.15 J
"Energy flow in food chains is always unidirectional". Justify this statement. Explain how the pesticides enter a food chain and subsequently get into our body.
What would happen if an organism is removed from the food chain?
In an ecosystem, herbivores represent ______.
Natural agents like ______ are the decomposition factors breaking complex forms into simpler units.
Animals that eat both plants and animals are called as Carnivores.
In the given food chain, suppose the amount of energy at the fourth trophic level is 5 kJ, what will be the energy available at the producer level?
Grass → Grasshopper → Frog → Snake → Hawk
In the following food chain, vertical arrows indicate the energy lost to the environment and horizontal arrows indicate energy transferred to the next trophic level. Which one of the three vertical arrows (A, C and E) and which one of the two horizontal arrows (B and D) will represent more energy transfer? Give reason for your answer.
A food chain in a forest ecosystem
Study the picture given below showing three food chains (a), (b) and (c) and answer the following questions:
- Name the type of ecosystems that exist in food chains (b) and (c).
- The first trophic level in all food chains is producers. Why? What percentage of solar energy do these producers capture for their use?
- Why are the arrows shown in the diagram in one direction only and not vice versa? Justify.
