Ecosystem

Q1 FREE PREVIEW

PYQ

The rate of formation of new organic matter by rabbit in a grassland is called:

aNet productivity

bSecondary productivity

cNet primary productivity

dGross primary productivity

✓ Correct answer: b) Secondary productivity

ExplanationSecondary productivity is defined as the rate of formation of new organic matter by consumers.Since rabbit is consumer the rate of new organic matters is secondary productivity.

Q2 FREE PREVIEW

PYQ

Which of the following would appear as the pioneer organisms on bare rocks?

aMosses

bGreen algae

cLichens

dLiverworts

✓ Correct answer: c) Lichens

ExplanationPioneer organisms are the first organisms to colonize a barren or disturbed environment, such as bare rocks, where no soil or vegetation exists initially.They play a crucial role in breaking down the rock surface and initiating the process of soil formation, which later supports more complex plant life.Lichens are the most common pioneer organisms on bare rocks.They consist of a symbiotic relationship between fungi and algae or cyanobacteria.Lichens are able to survive in harsh conditions and can gradually break down the rock surface to help form soil over time.Now, let's look at the other options: A - Mosses: Mosses can grow on bare rocks but generally come after lichens.They are not usually the first organisms to colonize bare rocks.B - Green algae: Green algae can grow on rocks, but they are more commonly found in aquatic environments or on moist surfaces, not typically as pioneer organisms on bare rocks.D - Liverworts: Liverworts are simple plants that can grow on moist, shaded rocks but are not typically the first to colonize bare rock surfaces compared to lichens.

Q3 FREE PREVIEW

PYQ

Which of the following is not used for construction of ecological pyramids?

aFresh weight

bDry weight

cNumber of individuals

dRate of energy flow

✓ Correct answer: a) Fresh weight

ExplanationEcological pyramids are constructed using: Number of individuals, Biomass (dry weight), Rate of energy flow.Fresh weight is not used, because water content varies and gives misleading values.

Q4

PYQ

Which one of the following statements for the pyramid of energy is incorrect?

aIts base is broad.

bIt shows energy content of different trophic level organisms.

cIt is inverted in shape.

dIt is upright in shape.

🔒

Answer & explanation — PYQ Pass

Options are free to see. Unlock the correct answer and full explanation with Pass.

Unlock · ₹149

Q5

PYQ

In relation to Gross primary productivity and Net primary productivity of an ecosystem, which one of the following statements is correct? [NEET 2020]

aGross primary productivity is always less than Net primary productivity

bGross primary productivity is always more than Net primary productivity

cGross primary productivity and Net primary productivity are one and same

dThere is no relationship between Gross primary productivity and Net primary productivity

🔒

Answer & explanation — PYQ Pass

Options are free to see. Unlock the correct answer and full explanation with Pass.

Unlock · ₹149

Q6

PYQ

Given below are two statements :

Statement I: The primary source of energy in an ecosystem is solar energy.

Statement II: The rate of production of organic matter during photosynthesis in an ecosystem is called net primary productivity (NPP).

In the light of the above statements, choose the most appropriate answer from the options given below:

[NEET 2025]

a

Statement I is correct but statement II is incorrect.

b

Statement I is incorrect but statement II is correct.

c

Both statement are correct I and statement II.

d

Both statement I and statement II are incorrect.

🔒

Answer & explanation — PYQ Pass

Options are free to see. Unlock the correct answer and full explanation with Pass.

Unlock · ₹149

Q7

PYQ

Who is known as the father of Ecology in India?

[NEET 2025]

a

Ram Udar

b

Birbal Sahni

c

S. R. Kashyap

d

Ramdeo Misra

🔒

Answer & explanation — PYQ Pass

Options are free to see. Unlock the correct answer and full explanation with Pass.

Unlock · ₹149

Q8

PYQ

Which of the following are primary consumers in a food chain?

[Re-NEET 2026]

a

Parasites

b

Predators

c

Herbivores

d

Carnivores

🔒

Answer & explanation — PYQ Pass

Options are free to see. Unlock the correct answer and full explanation with Pass.

Unlock · ₹149

Q9

PYQ

Match List I with List II :

List I	List II
A. Productivity	I. Gross primary productivity minus respiration losses
B. Net primary productivity	II. Rate of formation of new organic matter by consumers
C. Gross primary productivity	III. Rate of biomass production
D. Secondary productivity	IV. Rate of production of organic matter during photosynthesis

Choose the correct answer from the options given below:

[NEET 2026]

a

A-I, B-II, C-III, D-IV

b

A-III, B-I, C-IV, D-II

c

A-III, B-I, C-II, D-IV

d

A-I, B-III, C-IV, D-II

🔒

Answer & explanation — PYQ Pass

Options are free to see. Unlock the correct answer and full explanation with Pass.

Unlock · ₹149

Q10

PYQ

Which of the following statements are correct?

(a) Energy flow from producers to consumers is unidirectional

(b) Energy pyramid can never be inverted

(c) Transfer of energy follows the 1% law

Choose the correct answer from the options given below:

[Re-NEET 2026]

a

(a), (b) and (c)

b

(a) and (b) only

c

(a) and (c) only

d

(b) and (c) only

🔒

Answer & explanation — PYQ Pass

Options are free to see. Unlock the correct answer and full explanation with Pass.

Unlock · ₹149

Q11

PYQ

Which of the following is the unit of productivity of an Ecosystem?

[NEET 2025]

a

\(Kc\mathrm{al}{\mathrm{m}}^{-3}\)

b

\((Kc\mathrm{al}{\mathrm{m}}^{-2}){\mathrm{yr}}^{-1}\)

c

\({\mathrm{gm}}^{-2}\)

d

\(Kc\mathrm{al}{\mathrm{m}}^{-2}\)

🔒

Answer & explanation — PYQ Pass

Options are free to see. Unlock the correct answer and full explanation with Pass.

Unlock · ₹149

Q12

PYQ

Ecological pyramids represent the relationship between the organisms at different trophic levels and they are generally inverted for :

[NEET 2026]

a

Pyramid of energy in pond ecosystem

b

Pyramid of biomass in sea

c

Pyramid of number in grassland

d

Pyramid of biomass in grassland

🔒

Answer & explanation — PYQ Pass

Options are free to see. Unlock the correct answer and full explanation with Pass.

Unlock · ₹149

Q13

PYQ

In an ecosystem if the Net Primary Productivity (NPP) of first trophic level is \(100x\left(kcal{m}^{-2}\right)y{r}^{-1}\), what would be the GPP (Gross Primary Productivity) of the third trophic level of the same ecosystem?

[NEET 2024]

a

\(\frac{100x}{3x}\left(kcal{m}^{-2}\right)y{r}^{-1}\)

b

\(\frac{x}{10}\left(kcal{m}^{-2}\right)y{r}^{-1}\)

c

\(x\left(kcal{m}^{-2}\right)y{r}^{-1}\)

d

\(10x\left(kcal{m}^{-2}\right)y{r}^{-1}\)

🔒

Answer & explanation — PYQ Pass

Options are free to see. Unlock the correct answer and full explanation with Pass.

Unlock · ₹149

Q14

PYQ

In an ecosystem if the Net Primary Productivity (NPP) of first trophic level is \(100x\left(kcal{m}^{-2}\right)y{r}^{-1}\), what would be the GPP (Gross Primary Productivity) of the third trophic level of the same ecosystem?

[NEET 2024]

a

\(\frac{100x}{3x}\left(kcal{m}^{-2}\right)y{r}^{-1}\)

b

\(\frac{x}{10}\left(kcal{m}^{-2}\right)y{r}^{-1}\)

c

\(x\left(kcal{m}^{-2}\right)y{r}^{-1}\)

d

\(10x\left(kcal{m}^{-2}\right)y{r}^{-1}\)

🔒

Answer & explanation — PYQ Pass

Options are free to see. Unlock the correct answer and full explanation with Pass.

Unlock · ₹149

Q15

PYQ

Match List I with List II :

List I	List II
A. Decomposition	I. Accumulation of dark coloured amorphous colloidal substance
B. Detritus	II. Release of inorganic nutrients by activity of microbes in soil
C. Mineralisation	III. Breaking down of complex organic matter into inorganic substances
D. Humification	IV. Dead remains of plants and animals including fecal matter

Choose the correct answer from the options given below:

[NEET 2026]

a

A-I, B-II, C-III, D-IV

b

A-IV, B-III, C-I, D-II

c

A-III, B-IV, C-II, D-I

d

A-III, B-II, C-I, D-IV

🔒

Answer & explanation — PYQ Pass

Options are free to see. Unlock the correct answer and full explanation with Pass.

Unlock · ₹149

Q16

PYQ

Given below are two statements:
Statement I: In-ecosystem, there is unidirectional flow of energy of sun from producers to consumers.

Statement II: Ecosystems are exempted from 2^nd law of thermodynamics.
In the light of the above statements, choose the most appropriate answer from the options given below:

[NEET 2025]

a

Statement I is correct but statement II is incorrect

b

Statement I is incorrect but statement II is correct

c

Both statement I and statement II are correct

d

Both statement I and statement II are incorrect

🔒

Answer & explanation — PYQ Pass

Options are free to see. Unlock the correct answer and full explanation with Pass.

Unlock · ₹149

Q17

PYQ

Which one of the following is not a limitation of ecological pyramids?

[Re-NEET 2024]

a

Saprophytes are not given a place ecological pyramids.

b

It assumes a simple food chain, never exists in nature.

c

It accommodates a food web.

d

It does not take into account the same species belonging to two or more trophic levels

🔒

Answer & explanation — PYQ Pass

Options are free to see. Unlock the correct answer and full explanation with Pass.

Unlock · ₹149

Q18

PYQ

Which one of the following is not a limitation of ecological pyramids?

[Re-NEET 2024]

a

Saprophytes are not given a place ecological pyramids.

b

It assumes a simple food chain, never exists in nature.

c

It accommodates a food web.

d

It does not take into account the same species belonging to two or more trophic levels

🔒

Answer & explanation — PYQ Pass

Options are free to see. Unlock the correct answer and full explanation with Pass.

Unlock · ₹149

Q19

PYQ

Match the trophic levels with their correct species examples in grassland ecosystem.

(A) Fourth trophic level (i) Crow

(B) Second trophic level (ii) Vulture

(C) First trophic level (iii) Rabbit

(D) Third trophic level (iv) Grass

Select the correct option.

[NEET 2020]

a

A-ii, B-iii, C-iv, D-i

b

A-iii, B-ii, C-i, D-iv

c

A-iv, B-iii, C-ii, D-i

d

A-i, B-ii, C-iii, D-iv

🔒

Answer & explanation — PYQ Pass

Options are free to see. Unlock the correct answer and full explanation with Pass.

Unlock · ₹149

Q20

PYQ

The rate of decomposition is faster in the ecosystem due to all factors except:

[Re-NEET 2020]

a

Warm and moist environment

b

Presence of aerobic soil microbes

c

Detritus richer in lignin and chitin

d

Detritus rich in sugars

🔒

Answer & explanation — PYQ Pass

Options are free to see. Unlock the correct answer and full explanation with Pass.

Unlock · ₹149

Q21

PYQ

The amount of nutrients, such as carbon, nitrogen, phosphorus and calcium present in the soil at any given time is referred as

[NEET 2021]

a

Climax community

b

Standing state

c

Standing crop

d

Climax

🔒

Answer & explanation — PYQ Pass

Options are free to see. Unlock the correct answer and full explanation with Pass.

Unlock · ₹149

Q22

PYQ

Which of the following statements is not correct ?

[NEET 2021]

a

Pyramid of biomass in sea is generally upright.

b

Pyramid of energy is always upright

c

Pyramid of numbers in a grassland ecosystem is upright

d

Pyramid of biomass in sea is generally inverted.

🔒

Answer & explanation — PYQ Pass

Options are free to see. Unlock the correct answer and full explanation with Pass.

Unlock · ₹149

Q23

PYQ

Identify the correct statements :
A. Detrivores perform fragmentation.
B. The humus is further degraded by some microbes during mineralization.
C. Water soluble inorganic nutrients go down into the soil and get precipitated by a process called leaching.
D. The detritus food chain begins with living organisms.
E. Earthworms break down detritus into smaller particles by a process called catabolism.
Choose the correct answer from the option given below :

[NEET 2023]

a

B, C, D only

b

C, D, E only

c

D, E, A only

d

A, B, C only

🔒

Answer & explanation — PYQ Pass

Options are free to see. Unlock the correct answer and full explanation with Pass.

Unlock · ₹149

Q24

PYQ

In the equation, GPP \( -\mathrm{R}=\mathrm{NPP} \), \( R \) represents

[NEET 2021]

a

respiration losses

b

radiant energy

c

retardation factor

d

environment factor.

🔒

Answer & explanation — PYQ Pass

Options are free to see. Unlock the correct answer and full explanation with Pass.

Unlock · ₹149

Q25

PYQ

Which of the following statements is incorrect?

[Re-NEET 2020]

a

Energy content gradually increases from first to fourth trophic level

b

Number of individuals decreases from first trophic level to fourth trophic level

c

Energy content gradually decreases from first to fourth trophic level

d

Biomass decreases from first to fourth trophic level

🔒

Answer & explanation — PYQ Pass

Options are free to see. Unlock the correct answer and full explanation with Pass.

Unlock · ₹149

Q26

PYQ

In the equation GPP – R = NPP

GPP is Gross Primary Productivity

NPP is Net Primary Productivity.

R here is

a

Reproductive allocation

b

Photosynthetically active radiation

c

Respiratory quotient

d

Respiratory loss

🔒

Answer & explanation — PYQ Pass

Options are free to see. Unlock the correct answer and full explanation with Pass.

Unlock · ₹149

Q27

PYQ

In relation to gross primary productivity and net primary productivity of an ecosystem, which one of the following statements is correct?

a

Gross primary productivity is always more than net primary productivity.

b

Gross primary productivity and net primary productivity are one and same.

c

There is no relationship between Gross primary productivity and net primary productivity

d

Gross primary productivity is always less than net primary productivity.

🔒

Answer & explanation — PYQ Pass

Options are free to see. Unlock the correct answer and full explanation with Pass.

Unlock · ₹149

Q28

PYQ

The rate of decomposition is faster in the ecosystem due to following factors EXCEPT:

a

Warm and moist environment

b

Presence of aerobic soil microbes

c

Detritus richer in lignin and chitin

d

Detritus rich in sugars

🔒

Answer & explanation — PYQ Pass

Options are free to see. Unlock the correct answer and full explanation with Pass.

Unlock · ₹149

Q29

PYQ

In the equation
GPP - R = NPP

GPP is Gross Primary Productivity
NPP is Net Primary Productivity
R here is

[NEET 2023]

a

Respiratory quotient

b

Respiratory loss

c

Reproductive allocation

d

Photosynthetically active radiation

🔒

Answer & explanation — PYQ Pass

Options are free to see. Unlock the correct answer and full explanation with Pass.

Unlock · ₹149

Q30

PYQ

Which of the following statements is incorrect regarding the phosphorus cycle?

[Re-NEET 2020]

a

Phosphorus solubilising bacteria facilitate the release of phosphorus from organic remains

b

There is appreciable respiratory release of phosphorus into atmosphere

c

It is sedimentary cycle

d

Phosphates are the major form of phosphorus reservoir

🔒

Answer & explanation — PYQ Pass

Options are free to see. Unlock the correct answer and full explanation with Pass.

Unlock · ₹149

Q31

PYQ

In relation to Gross primary productivity and Net primary productivity of an ecosystem, which one of the following statements is correct?

[NEET 2020]

a

Gross primary productivity is always less than Net primary productivity

b

Gross primary productivity is always more than Net primary productivity

c

Gross primary productivity and Net primary productivity are one and same

d

There is no relationship between Gross primary productivity and Net primary productivity

🔒

Answer & explanation — PYQ Pass

Options are free to see. Unlock the correct answer and full explanation with Pass.

Unlock · ₹149

Practice more NEET Biology PYQs