Tag: food chain and food web

Questions Related to food chain and food web

Which of the following statement defines the difference between the food chain and food web?

  1. Food chain demonstrates the interdependence.

  2. Food web demonstrates the interlinked food chain.

  3. Food chain is an exchange of energy.

  4. None of the above


Correct Option: B

A peacock eats snakes which eat frogs. These eat hoppers which in turn thrive on leaves of the plants. The peacock is

  1. Primary consumer

  2. Secondary consumer

  3. Decomposer

  4. Apex of the food pyramid


Correct Option: D
Explanation:

Apex of the food pyramid is the tip of the food pyramid. In the given food pyramid, peacock eats snakes which eat hoppers which in turn eats leaves of the plants. Hence, the peacock is the apex of food pyramid and plants are the base of the food pyramid.  Hoppers are primary consumer and snakes are secondary consumers of the given food pyramid.

Thus, the correct answer is 'Apex of the food pyramid.'

Extinction of a species in a food chain is compensated in

  1. Ecological pyramid

  2. Food web

  3. Food chain

  4. None of the above


Correct Option: B
Explanation:

Food web is interconnected food chains in an ecosystem. Extinction of a species in a food chain is compensated in food web. When a particular species in a food chain becomes extinct, it is compensated by the remaining generalized species at the same trophic level.

Thus, the correct answer is 'Food web.'

Which of the following statements about food chains are correct?
(a) Removal of 80% tigers resulted in increased growth of vegetation.
(b) Removal of most carnivores resulted in an increased population of deer.
(c) Length of the food chain is limited to 3-4 trophic levels due to energy loss.
(d) Length of the food chain may vary from 2-3 trophic levels.

  1. a, d

  2. a, b

  3. b, c

  4. c, d


Correct Option: C
Explanation:

In a food chain, the carnivores eat up herbivores, or in other words, the secondary consumers consume the primary consumers. So, we can say that if the number of carnivores decreases, the number of herbivores like deer go on decreasing as they will not get eaten up. So, removal of most of the carnivores will result in an increased population of deer. 

Apart from this, we also know that as we move from one tropic level to another, the amount of energy goes on decreasing. This is according to the 10% law according to which, at each trophic level, 10& energy is lost. So, each food chain is only 3-4 tropic levels long due to these energy losses. 
So, option b and c is the correct option.
So the correct option is C.

Networking of different food chains in an ecosystem provides

  1. Stability

  2. Instability

  3. Origin of new species

  4. None of the above


Correct Option: A
Explanation:

Food web is constituted by various interlinked food chains in a community. Networking of different food chains in an ecosystem provides stability to the ecosystem. Due to interconnecting food chains, relationships between the species remain constant over relatively long periods of time.

Thus, the correct answer is 'Stability.'

Which of the following occupies more than one trophic level in the same ecosystem at the same time?

  1. Sparrow

  2. Goat

  3. Frog

  4. Lion


Correct Option: A
Explanation:

In an ecosystem, there are various trophic levels. Each trophic level consists of a particular organisms. It consists of producers, consumers, decomposers. The first trophic level consists of producers such as plants. The second trophic level consists of primary consumers. The third trophic level consists of secondary consumers. There are certain organisms which occupy more than one trophic level in the same ecosystem at the same time. An example include sparrow. It feeds upon grains. Hence, it is called as primary consumer and occupies second trophic level. It also feeds upon insects. Hence, it is called as secondary consumer and occupies third trophic level.

Thus, the correct answer is 'Sparrow.'

Which of the following may occupy any trophic level in an ecosystem?

  1. Plankton

  2. Aquatic animals

  3. Decomposers

  4. Aquatic plants


Correct Option: B
Explanation:

There are various trophic levels in a food chain. The first trophic level consists of primary producers such as plant. The second trophic level consists of herbivores or primary consumers. The third trophic level consists of carnivores or secondary consumers. Decomposers are present at the top trophic level. Phytoplankton occupies the first trophic level in an ecosystem. The zooplankton feeding upon phytoplankton occupies the second trophic level in an ecosystem. Aquatic animals occupy any trophic level in an ecosystem. Aquatic animals such as zooplankton occupies first trophic level. Aquatic animals such as small fish occupies second trophic level. Aquatic animals such as large fish occupies third trophic level. The aquatic plants occupy first trophic level. 

Thus, the correct answer is 'Aquatic animals.'

A group of interconnected food chains is called

  1. complex food chain

  2. food web

  3. food cycle

  4. pyramid of biomass


Correct Option: B
Explanation:

A web of interconnected food chains is known as food web.

The food web has various interdependent food chains and establishes ecological balance.
So, the correct option is 'food web'.

Trophic levels are formed by:

  1. plants only

  2. animals only

  3. organisms linked in food chains

  4. top consumers in food chain


Correct Option: C
Explanation:

Trophic means food. The animals linked in the food chain form various trophic levels. A food chain is a series of organisms that eat and get eaten.

So, the correct option is 'organisms linked to the food chain'.

Which is not true about a complex food web?

  1. Populations tend to remain about the same size

  2. Energy levels remain about the same for all trophic levels

  3. Inputs are constant and outputs are minimal except for heat

  4. Most of the energy entering the system maintains the whole community


Correct Option: B
Explanation:

The amount of energy at each trophic level decreases as it moves through an ecosystem. As little as 10% of the energy at any trophic level is transferred to the next level; the rest is lost largely through metabolic processes as heat. Food webs illustrate how energy flows through ecosystems, including how efficiently organisms acquire and use it. Autotrophs, producers in food webs, can be photosynthetic or chemosynthetic. They use light energy to synthesize their own food, while chemoautotrophs use inorganic molecules. Heterotrophs cannot synthesize their own energy, but must obtain it from autotrophs in food webs.

So the correct option is 'energy levels remain about the same for all trophic levels.'