1. The term ecosystem was coined by
(a) E. Haeckel (b) E.Warming
(c) E.P. Odum (d) A. G. Tansley.
2. Which one of the following is a characteristic feature
of cropland ecosystem?
(a) Absence of weeds
(b) Ecological succession
(c) Absence of soil organisms
(d) Least genetic diversity (NEET-I 2016)
3. Vertical distribution of different species occupying
different levels in a biotic community is known as
(a) zonation (b) pyramid
(c) divergence (d) stratification.
(2015 Cancelled)
4. Which one of the following is not a functional unit
of an ecosystem?
(a) Energy flow (b) Decomposition
(c) Productivity (d) Stratification (2012)
5. Which one of the following is one of the
characteristics of a biological community?
(a) Stratification (b) Natality
(c) Mortality (d) Sex-ratio (2010)
6. Which of the following is the most stable ecosystem?
(a) Mountain (b) Ocean
(c) Forest (d) Desert
7. 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 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.
(NEET 2020)
8. The mass of living material at a trophic level at a
particular time is called
(a) net primary productivity
(b) standing crop
(c) gross primary productivity
(d) standing state. (2015 Cancelled)
9. In an ecosystem the rate of production of organic
matter during photosynthesis is termed as
(a) secondary productivity
(b) net productivity
(c) net primary productivity
(d) gross primary productivity. (2015 Cancelled)
10. Secondary productivity is rate of formation of new
organic matter by
(a) consumers (b) decomposers
(c) producers (d) parasites.
(NEET 2013)
11. The rate of formation of new organic matter by
rabbit in a grassland, is called
(a) net productivity
(b) secondary productivity
(c) net primary productivity
(d) gross primary productivity. (Mains 2012)
12. Mass of living matter at a trophic level in an area at
any time is called
(a) standing crop (b) detritus
(c) humus (d) standing state. (2011)
13. The biomass available for consumption by the
herbivores and the decomposers is called
(a) net primary productivity
(b) secondary productivity
(c) standing crop
(d) gross primary productivity.
14. Which one of the following ecosystem types has the
highest annual net primary productivity?
(a) Tropical deciduous forest
(b) Temperate evergreen forest
(c) Temperate deciduous forest
(d) Tropical rainforest (2007)
15. Which of the following is expected to have the
highest value (gm/m2
/yr) in a grassland ecosystem?
(a) Secondary production
(b) Tertiary production
(c) Gross production (GP)
(d) Net production (NP) (2004)
16. The rate at which light energy is converted into
chemical energy of organic molecules is the
ecosystem’s
(a) net secondary productivity
(b) gross primary productivity
(c) net primary productivity
(d) gross secondary productivity. (1998)
17. Which of the following ecosystem has the highest
gross primary productivity?
(a) Mangroves (b) Rainforest
(c) Grassland (d) Coral reef (1997)
18. Maximum solar energy is trapped by
(a) planting trees
(b) cultivating crops
(c) growing algae in tanks
(d) growing grasses. (1993)
19. A very efficient converter of solar energy with net
productivity of 204 kg/m2
or more is the crop
(a) wheat (b) sugarcane
(c) rice (d) bajra.
1. (d) : The term ecosystem was coined by A.G.
Tansley in 1935.
2. (d) : Cropland ecosystem is an artificial or man-
made terrestrial ecosystem which is created and
maintained by human beings for their maximum
benefits. Therefore, they will have least genetic diversity.
3. (d)
4. (d) : Four important functional aspects of the
ecosystem are productivity, decomposition, energy flow
and nutrient cycling.
5. (a) : The characteristics of biological community
are dominance, species diversity, trophic organisation,
stratification, dynamism and stability. Organisms are not
uniformly distributed throughout a community. They
usually occur in definite zones. This spatial arrangement
of populations is called stratification. Structurally
a community may be divided horizontally into
subcommunities. This horizontal division constitutes
the zonation in the community. Natality, mortality, age
structure and sex ratio are the basic characteristics of a
population.
6. (b) : Of all the ecosystems, ocean is the largest
and most stable ecosystem. Aquatic life is protected
from vigorous climates and weather that are climatic
conditions, problem of water supply, food, fire and
artificial forces such as industrialization, farming and
grazing are lacking in the oceans. The sea is continuous
and not separated as land and freshwater habitats.
7. (b) : Gross primary productivity (GPP) is the rate
of production of organic matter during photosynthesis.
A considerable amount of GPP is utilised by plants in
respiration. GPP minus respiration losses (R) is the net
primary productivity GPP – R = NPP.
Therefore, GPP is always more than NPP.
8. (b) : Standing crop is the total amount of living
material in a specified population at a particular time,
expressed as biomass (standing biomass) or its equivalent
in terms of energy. The standing crop may vary at
different times of the year; for example, in a population
of deciduous trees between summer and winter.
9. (d) : The amount of energy accumulation in green
plants as biomass or organic matter per unit area over a
time period is known as primary productivity. The rate
of total capture of energy, or the rate of total production
of organic material (biomass), is known as gross primary
productivity.
10. (a) 11. (b)
12. (a) : Standing crop is the total amount of living
material in a specified population at a particular time,
expressed as biomass (standing biomass) or its equivalent
in terms of energy. The standing crop may vary at
different times of the year; for example, in a population
of deciduous trees between summer and winter.
13. (a) : The total organic matter synthesised by the
producers in the process of photosynthesis per unit time
and area is known as gross primary productivity. Net
primary productivity is equal to the rate of organic matter
created by photosynthesis minus the rate of respiration
and other losses. It is actually the biomass available for
consumption by the herbivores and the decomposers.
14. (d) : Net primary productivity is the total organic
matter stored by producers per unit area per unit time.
Gross primary productivity is the total organic matter
synthesised by producers in the process of photosynthesis
per unit area per unit time. So,
Net primary productivity = Gross productivity –
Respiration and other losses
Tropical rainforests occur over equatorial/subequatorial
regions with abundant warmth and rainfall. Diversity
and productivity are maximum as compared to other
regions.
15. (c) : Productivity is rate of accumulation of energy
containing organic matter by an ecosystem per unit area
per unit time. It is of two types- primary and secondary.
Productivity at producer level is known as primary
productivity. It is two types: Gross primary productivity
is primary productivity including that amount which is
utilized in respiration and other metabolic activities. Net
primary productivity (NPP) is primary productivity in
excess to that which is utilised in respiration and other
metabolic activities.
NPP = GP – Respiration
Secondary productivity is productivity at consumer
level. Since gross production includes total production
including the amount utilized in respiration and other
metabolic activities so it is more than other forms of
productivity.
16. (b)
17. (b) : Gross primary productivity is the total rate
of photosynthesis, including the organic matter used
up in respiration during the measurement period.
Tropical evergreen/rainforests occur over equatorial/
subequatorial regions with abundant warmth and rainfall
(200–350 cm/yr) almost throughout the year. The forests
are impenetrable (= jungle) with maximum diversity,
e.g., 200 types of trees in one hectare, 70–80% of all
insects 80–85% of all birds. Productivity is maximum
here, 12000 kcal/m2/yr.
18. (c) : Maximum solar energy is trapped by growing
algae in tanks. The light spectrum of red and blue light
are most effective in performing photosynthesis for
growing algae.
19. (b)