Tag: evs

Questions Related to evs

Which of the following trophic levels includes a bird feeding on both insects and berries?

  1. Primary consumer

  2. Secondary consumer

  3. Tertiary consumer

  4. Both A and B

  5. Both A and C


Correct Option: D
Explanation:

Primary consumers are the organisms that feed on producers. Since the bird is feeding on berries (producer), it is a primary consumer. The organisms that feed on primary consumers are termed as secondary consumers. Since the bird is feeding on insects (primary consumer), it is a secondary consumer as well. This makes option D correct answer. 

All of the following organisms are correctly paired with their trophic level except

  1. Tree- producer

  2. Hawk- primary consumer

  3. Fungi- detritivore

  4. Fox- secondary consumer

  5. Grasshopper- primary consumer


Correct Option: B
Explanation:
The tree is a producer. Producers are any kind of green plant. Green plants make their food by taking sunlight and using the energy to make sugar.
Hawk is a tertiary consumer which eats secondary consumers like hawks eat owls in a food chain. 
Fungi is a detritivore. They are heterotrophs that obtain nutrients by consuming detritus.
Fox is a secondary consumer. They eat primary consumers. They are carnivores (meat-eaters) and omnivores (animals that eat both animals and plants).
Grasshopper is a primary consumer. They are animals that eat primary producers.
Therefore, the correct answer is option B.

Which of the following best describes the trophic level within an ecosystem?

  1. Size of food eaten at that level

  2. Nutrient source of the organisms in each level

  3. Stages in ecological succession

  4. Habitats of the organisms within that level

  5. Elevation above sea level


Correct Option: A
Explanation:

An ecosystem is made up of organisms that differ in the energy source that they depend on upon and how they provide energy for other organisms in the food web. The steps of the nutritive food chain in the ecosystem is known as trophic levels. In other words, it is the position that an organism occupies in a food chain depending on what it eats, and what eats it.

Which of the following limits the number of trophic levels maintained by an ecosystem?

  1. The number of species

  2. The population size

  3. The loss of potential energy

  4. The number of individuals

  5. The hours of sunshine


Correct Option: C
Explanation:

With each trophic level, only 10% potential energy is transferred and 90% is lost as heat in respiration. The longer the food chain, the lesser is the energy transfer efficiency. To increase the energy transfer efficiency, food chains must be smaller with a limited number of trophic levels. Thus, the correct answer is C.

Which of the following is false?

  1. Quantity of biomass in trophic level at a particular period is called as standing crop.

  2. The energy content in trophic level is determined by considering a few individuals of a species in that trophic level.

  3. The succession that occurs in newly cooled lava is called as primary succession.

  4. Rate of succession is faster in secondary succession.

  5. Phytoplanktons are the pioneers in the aquatic ecosystem.


Correct Option: B
Explanation:

Trophic level refers to each levels in the  ecological pyramid and is designated as per their position in the food chain. The trophic level starts from 1 -which represents the primary producers and it moves upto  primary consumers- level 2, secondary consumers -level 3 and tertiary consumers at level 4 or 5. In an aquatic ecosystem, the phytoplanktons are the pioneers and primary producers along with the algae and cyanobacteria. Standing crop refers to the mass of living material present at a trophic level at a particular time. The ecological succession takes place from primary to secondary and reaches a climax stage. primary succession refers to the ecological succession that takes place where no living organisms ever existed. for eg. the sucession that occurs in a newy cooled lava.  Moreover, it has been seen that the rate of succession is faster in secondary than the primary succession as soil is already present in case of secondary succession.

In a food chain, deer is eaten by lion and deer east vegetation. Which one of the statements given is true?
(P) Lion is second order consumer and deer is first order consumer.
(Q) Lion is predator and deer is prey.
(R) Lion is first order consumer and deer is second order consumer.
(S) Lion is third order consumer and deer is second order consumer.

  1. Only (P) and (Q)

  2. Only (Q) and (R)

  3. Only (P) and (S)

  4. Only (P) and (R)


Correct Option: A
Explanation:

In a food chain where a deer feeds on producers and lion feeds on the deer then, the deer is a first order consumer and the lion is a second order consumer, and as the lion feeds in the deer, lion is the predator and the deer is the prey. 

Thus, the correct answer is option A. 

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.'

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.

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.'