Ecosystem NCERT

The given figure shows pyramid of numbers in a grassland ecosystem. What will be be true for pyramid of numbers ?

\(
\begin{array}{|l|l|}
\hline \text { I: } & \begin{array}{l}
\text { A pyramid of numbers shows graphically the } \\
\text { population, or abundance, in terms of the number of } \\
\text { individual organisms involved at each level in a food } \\
\text { chain. }
\end{array} \\
\hline \text { II: } & \begin{array}{l}
\text { The pyramid shows the number of organisms in each } \\
\text { trophic level and it does not consider individual sizes } \\
\text { or biomass. }
\end{array} \\
\hline \text { III: } & \begin{array}{l}
\text { It is not necessary that the pyramid is always } \\
\text { upright. For example, it will be inverted if beetles are } \\
\text { feeding from the output of forest trees, or parasites } \\
\text { are feeding on large host animals. }
\end{array} \\
\hline
\end{array}
\)

Energy flow and nutrient cycling are two important components of an ecosystem. What will be true comparison of the two ?

Vertical distribution of different species occupying different levels in an ecosystem is called :

Productivity is the rate of production of biomass expressed in terms of :
i. \( \left(\mathrm{kcal} \mathrm{m}^{-3}\right) \mathrm{yr}^{-1} \)
ii. \( \mathrm{g} \mathrm{m}^{-2} \mathrm{yr}^{-1} \)
iii. \( \mathrm{g} \mathrm{m}^{-1} \mathrm{yr}^{-1} \)
iv. \( \left(\mathrm{kcal} \mathrm{m}^{-2}\right) \mathrm{yr}^{-1} \)

In an ecosystem, the rate of production of organic matter during photosynthesis is called as its :

Net primary productivity is the gross primary productivity minus :

Secondary productivity in an ecosystem can be defined as :

The annual net primary productivity of whole biosphere is approximately:

Humus:

The given pyramid of biomass shows a sharp decrease in biomass at higher trophic levels. What can be the reason for this sharp decrease ?

I: The respiration cost increases sharply along successive higher trophic levels.
II: There can be lower amounts of biomass at the bottom of the pyramid if the rate of primary production per unit biomass is high.

By process of leaching during decomposition of detritus, water soluble :

During decomposition of detritus, the step that is performed by bacteria and fungi includes :

The process of mineralization by micro-organisms helps in the release of :

Decomposition of detritus is rapid when :

Among the following, where do you think the process of decomposition would be the fastest ?

What percentage of photosynthetic active radiation is captured by plants ?

Suppose in an area, the energy present in total incident sunlight falling on primary producers is \( 10,00,000 \mathrm{~J} \) and about \( 10,000 \mathrm{~J} \) is converted by them into biomass. What percent of PAR have the primary producers been able to convert?

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
\(
\begin{array}{|l|l|}
\hline \text { Assertion (A): } & \begin{array}{l}
\text { Some aquatic ecosystems have inverted } \\
\text { biomass pyramids. }
\end{array} \\
\hline \text { Reason (R): } & \begin{array}{l}
\text { The pyramid of energy is also inverted } \\
\text { in such ecosystems. }
\end{array} \\
\hline
\end{array}
\)
In the light of the above statements, choose the most appropriate answer from the options given below :

The ecological pyramids that can never be inverted in a natural ecosystem include :
\(
\begin{array}{|l|l|}
\hline \text { I: } & \text { pyramid of numbers } \\
\hline \text { II: } & \text { pyramid of energy in any ecosystem } \\
\hline \text { III: } & \text { pyramid of biomass in the sea } \\
\hline
\end{array}
\)

The figure shows an inverted pyramid of biomass. What will be true for such a pyramid ?

I: An example of such a pyramid will be the pyramid of biomass in a pond ecosystem, where the standing crop of phytoplankton, the major producers, at any given point will be lower than the mass of the heterotrophs.
II: The phytoplankton reproduce very quickly, but have much shorter individual lives.

The three steps of decomposition occur :

On the land, almost all primary production is performed by :

Consider the two statements :
\(
\begin{array}{|l|l|}
\hline \text { Statement I: } & \begin{array}{l}
\text { No energy that is trapped into an organism } \\
\text { remains in it forever. }
\end{array} \\
\hline \text { Statement II: } & \begin{array}{l}
\text { All animals depend on plants [directly or } \\
\text { indirectly] for their food requirements. }
\end{array} \\
\hline
\end{array}
\)

Of the total solar radiation that falls on the leaves of the plants, about what percent is captured by them ?

Primary carnivores are, most aptly, characterized as:

The detritus food chain :
\(
\begin{array}{|l|l|}
\hline \text { I: } & \text { begins with dead organic matter } \\
\hline \text { II: } & \begin{array}{l}
\text { is the major conduit of energy flow in aquatic } \\
\text { ecosystem. }
\end{array} \\
\hline
\end{array}
\)

In a terrestrial ecosystem, a much larger fraction of energy flows through the :

Consider the following statements:
\(
\begin{array}{|l|l|}
\hline \text { I: } & \begin{array}{l}
\text { In an aquatic ecosystem, GFC is the major conduit } \\
\text { for energy flow. }
\end{array} \\
\hline \text { II: } & \begin{array}{l}
\text { In a terrestrial ecosystem, DFC is the major conduit } \\
\text { for energy flow. }
\end{array} \\
\hline \text { III: } & \text { GFC and DFC are not interconnected at any level. } \\
\hline
\end{array}
\)
Which of the above statements are true ?

Each trophic level has a certain mass of living material at a particular time, best called as :

Consider the given two statements :
\(
\begin{array}{|l|l|}
\hline \text { I: } & \begin{array}{l}
\text { In most ecosystems, all the ecological pyramids are } \\
\text { largely upright. }
\end{array} \\
\hline \text { II: } & \begin{array}{l}
\text { Pyramid of energy can be a notable exception to the } \\
\text { above rule. }
\end{array} \\
\hline
\end{array}
\)

Pyramid of numbers is :

Secondary productivity refers to :

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
\(
\begin{array}{|l|l|}
\hline \text { Assertion (A): } & \begin{array}{l}
\text { Saprophytes play a vital role in the } \\
\text { ecosystem. }
\end{array} \\
\hline \text { Reason (R): } & \begin{array}{l}
\text { Saprophytes are accorded the highest } \\
\text { trophic level in a food chain or a food } \\
\text { web. }
\end{array} \\
\hline
\end{array}
\)
In the light of the above statements, choose the most appropriate answer from the options given below :

Net primary productivity (NPP) is the biomass available to herbivores and decomposers. Which of the following is correct ?

Consider the two statements :
I: Food chains rarely extend for more than 4 or 5 levels. Consumers at each level convert, on an average, only
II: about \( 10 \% \) of the chemical energy in their food to their own organic tissue.

Approximately, what percent of energy is transferred to each trophic level from the lower trophic level in an ecosystem ?

Standing crop is :

Standing state refers to :

Which of the following is correct about primary productivity ?

Primary productivity of an ecosystem depends on :

Q10. Match the following:
1. GPP – A. Biomass available to consumers
2. NPP – B. Total photosynthate including respiration
3. Secondary productivity – C. Rate of organic matter formation by consumers
4. Standing crop – D. Living biomass per unit area at a given time

Which of the following is the correct sequence of decomposition ?

Humification leads to formation of :

Which step of decomposition is correctly matched ?

Decomposition is favoured under:

Which is incorrect regarding humus ?

Mineralisation is :

Which process during decomposition converts detritus into smaller particles ?

The rate of decomposition is slower when :

Which is true for grazing food chain ?