Test: Energy Flow (NCERT)


15 Questions MCQ Test NCERTs for NEET: Textbooks, Tests & Solutions | Test: Energy Flow (NCERT)


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Attempt Test: Energy Flow (NCERT) | 15 questions in 15 minutes | Mock test for NEET preparation | Free important questions MCQ to study NCERTs for NEET: Textbooks, Tests & Solutions for NEET Exam | Download free PDF with solutions
QUESTION: 1

Given figure represents food chains of a deciduous woodland linked together to form a food web.

Which of the following constitute first trophic level of the grazing food chain and the detritus food chain respectively? 

Solution:

In grazing food chain (GFC), producers constitute the first trophic level whereas detritus food chain (DFC) begins with detritus or dead organic matter.

QUESTION: 2

Study the food web given below and answer the questions that follow.

Which of the following organisms in the given food web acts as a secondary consumer?

Solution:

In the given food web, organisms I (phytoplanktons) act as producers, organisms II, V and VII act as primary consumers as they feed on producers, organisms III and VI act as secondary consumers as they upon primary consumers, and organism IV acts as a tertiary consumer.

QUESTION: 3

Percentage of photosynthetically active radiation (PAR) in the incident solar radiation is

Solution:

Less that 50% of the solar energy incident over earth is PAR (photosynthetically active radiation).

QUESTION: 4

Percentage of photosynthetically active radiation (PAR) that is captured by plants in synthesis of organic matter is?

Solution:

About 1−5% of incident solar energy or 2−10% of PAR is captured by the photosynthetic organisms for the synthesis of organic matter(Gross primary productivity). Roughly 20% of it is consumed in respiration so that net capture of energy(net primary productivity) is 0.8−4% of incident radiation or 1.6−8% of PAR.

QUESTION: 5

Read the following statements and select the correct ones.
(i) A given species may occupy more than one trophic level in the same ecosystem at the same time.
(ii) Productivity of an aquatic ecosystem is less than that of a terrestrial ecosystem.
(iii) Producers constitute the first trophic level of a detritus food chain.

Solution:

Decomposers and detritivores constitute the first trophic level of a detritus food chain.

QUESTION: 6

If 10 joules of energy is available at the producer level, then amount of energy present at the level of secondary consumer is

Solution:

Only 10 % of energy is transferred from one trophic level to the next trophic level of a food chain (ten percent law, given by Linderman). In present case, energy available at producer level is 10 J. Hence energy at primary consumer level would be 1 H (10% of 10 J). Similarly, at secondary consumer level, energy present will be 0.1 J (100 % of 1 J).

QUESTION: 7

Organisms which are associated with first as well as third trophic level are

Solution:

Trophic level is a functional level. A single species may occupy more than one trophic level. Insectivorous plants are producers, occupying first trophic level. They also eat insects and thus, occupy third trophic level also.

QUESTION: 8

In the given food web, an increase in the population of hawks will not result in

Solution:

If population of hawks would increase, they would feed on more lizards which will result in decrease of lizard population.

QUESTION: 9

In a grassland ecosystem, if the number of primary producers is approximately 6 million plants, the number of the top carnivores (in million), which may be supported by it may be ________ million.

Solution:

In a grassland ecosystem, the pyramid of numbers is upright. If primary producers are approximately 6 million plants, then number of top carnivores must be less than 6 milliion. Hecne, according to the option given, there would be 3 million top carnivores.

QUESTION: 10

Which one of the following animals may occupy more than one trophic levels in the same ecosystem at the same time?

Solution:

A single species may occupy more than one trophic level. Sparrow being omnivorous can be a primary consumer if it feeds on seeds, fruits and peas or a secondary consumer if it feeds on insects and worms.

QUESTION: 11

Study the following statements concerning food chains and select the correct ones.
(I) Removal of 80% tigers from an area resulted in greatly increased growth of vegetation.
(II) Removal of most of the carnivores resulted in an increased population of deers.
(III) the length of food chains is generally limited to 3-4 trophic levels due to energy loss.
(IV) the length of food chains may vary from 2 to 8 trophic levels. 

Solution:

If carnivores, which feed on deers are removed, then the deer population will flourish. Removal of 80% of tigers from an area will cause increase in population of herbivores, which would further feed more on vegetation, decreasing its growth. The length of food chain is limited to 3-4 trophic levels as only 10% of energy is transferred to next trophic level. Hence after 3-4 trophic levels there is very little or no energy left to sustain more trophic levels. 

QUESTION: 12

Given food web contains some missing organisms, (1), (2), (3) and (4). Identify these organisms and select the correct answer.


Solution:

A lion feeds on a deer.
Deer are the primary consumer.
Fox acts a secondary consumer and feeds on a primary consumer such as Rabbit.
Frog feeds on a grasshopper and acts as a primary consumer.
Rat acts as prey for both Snake and a hawk.

QUESTION: 13

Match column I with column II and select the correct option from the given codes.

Solution:
QUESTION: 14

In an aquatic ecosystem, the organism present at the trophic level equivalent to cows in grasslands is?

Solution:

In an aquatic ecosystem, the important herbivores are zooplankton, larvae, tadpoles, etc. Cows in grasslands also act as herbivores as these feed on producers. Thus, both cows and zooplankton occupy second trophic level in terrestrial and aquatic ecosystem respectively.

QUESTION: 15

Read the given statements and select the correct option.
Statement 1: Herbivores are also called as first-order consumers.
Statement 2: Herbivores obtain their food directly from plants.

Solution:

First-order consumers are animals that eat plants called herbivores. They are the first step in the food chain.

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