Question 1

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

Accepted Answer

Productivity is defined as the rate of biomass production. Gross primary productivity (GPP) of an ecosystem is the rate of production of organic matter during photosynthesis. Net primary productivity (NPP) is the gross primary productivity minus respiration losses (R), which is the available biomass for the consumption to heterotrophs. Secondary productivity is defined as the rate of formation of new organic matter by consumers. Therefore, the correct matching is A-III, B-I, C-IV, D-II. Answer:

Question 2

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

Accepted Answer

The pyramid of biomass in a sea or aquatic ecosystem is generally inverted because the biomass of fishes (primary and secondary consumers) far exceeds that of phytoplankton (producers). The pyramid of number in a grassland is upright. The pyramid of energy is always upright in all ecosystems because energy is lost as heat at each trophic level. The pyramid of biomass in a grassland is upright. Answer: Pyramid of biomass in sea

Question 3

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

Accepted Answer

Statement (a) is correct because energy flow in an ecosystem is strictly unidirectional, moving from producers to herbivores and then to carnivores. Energy cannot flow back in the reverse direction. Statement (b) is correct because the pyramid of energy is always upright and can never be inverted. At each successive trophic level, a significant amount of energy is lost as heat to the environment. Statement (c) is incorrect because the transfer of energy from one trophic level to the next follows

Question 4

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

Accepted Answer

In a food chain, producers (plants) form the first trophic level. The organisms that feed directly on these producers are called primary consumers. Since they consume plants, they are herbivores. Carnivores and predators feed on other animals, making them secondary or tertiary consumers. Parasites can occupy various trophic levels depending on their host.

Question 5

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 the activity of microbes in

Accepted Answer

Decomposition is the process of breaking down complex organic matter into inorganic substances like carbon dioxide, water, and nutrients. Detritus constitutes the dead remains of plants and animals, including faecal matter, which serves as the raw material for decomposition. Mineralisation is the process by which microbes further degrade humus to release inorganic nutrients into the soil. Humification leads to the accumulation of a dark-coloured, amorphous, colloidal substance called humus, whic

Question 6

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

Accepted Answer

The rate of biomass production is called productivity. It is expressed in terms of gm ^ -2 yr ^ -1 or ( KCal m ^ -2 ) yr ^ -1 to compare the productivity of different ecosystems.

Question 7

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 ecosyste

Accepted Answer

Primary source of energy in the ecosystem is solar energy. Gross primary productivity of an ecosystem is the rate of production of organic matter during photosynthesis. Hence, statement I is correct but statement II is incorrect.

Question 8

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 2nd law of thermodynami

Accepted Answer

Sun is the only source of energy for all ecosystems on Earth, except for deep sea-hydro-thermal ecosystem. The energy flow is unidirectional from the sun to producers and then to consumers. Ecosystems are not exempted from the second law of thermodynamics. They need a constant supply of energy to synthesise the molecules they require to counteract the universal tendency towards increasing disorderliness.

Question 9

Consider the pyramid of energy of an ecosystem given below: If T_4 is equivalent to 1000 J , what is the value at T_1 ?

Accepted Answer

According to the given pyramid of energy, if T _4 is equivalent to 1000 J , then according to the 10 percent law, which states that only 10 percent of energy is transferred to each trophic level from the lower trophic level, the value at T _1 is 10,00,000 ~J . aligned & T_1=10,00,000 ~J \ & T_2= 10 100 10,00,000=1,00,000 ~J \ & T_3= 10 100 100000=10,000 ~J \ & T_4= 10 100 10000=1000 ~J aligned

Question 10

In an ecosystem if the Net Primary Productivity (NPP) of first trophic level is 100 x ( kcal m ^ -2 ) yr ^ -1 , what would be the GPP (Gross Primary Productivity) of the third trophic level of the sam

Accepted Answer

NPP at first trophic level would be the GPP for second trophic level. NPP at second trophic level would be GPP for third trophic level. Therefore, 100 x ( kcal / m ^2 / yr . ) would be GPP at second trophic level and 100 x 10 \% ( kcal / m ^2 / yr ) i.e., 10 x ( kcal / m ^2 / yr ) energy would be GPP at third trophic level.

Question 11

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

Accepted Answer

There are certain limitation of ecological pyramids. Such as : - It does not take into account the same species belonging to two or more trophic levels. - It assumes a simple food chain, something that almost never exists in nature. - It does not accommodate a food web. - Saprophytes are not given any place in ecological pyramids even though they play a vital role in the ecosystem.

Ecosystem — Previous Year Questions & Solutions