Organisms and Populations NCERT

The given age pyramid represents a :

In the given figure, I, B, D and E stand for :-

\(
\begin{array}{|l|l|l|l|l|}
\hline & \text { I } & \text { B } & \text { D } & \text { E } \\
\hline \text { 1. } & \text { Emigration } & \text { Natality } & \text { Mortality } & \text { Immigration } \\
\hline \text { 2. } & \text { Emigration } & \text { Mortality } & \text { Natality } & \text { Immigration } \\
\hline \text { 3. } & \text { Immigration } & \text { Natality } & \text { Mortality } & \text { Emigration } \\
\hline \text { 4. } & \text { Immigration } & \text { Mortality } & \text { Natality } & \text { Emigration } \\
\hline
\end{array}
\)

Identify the incorrectly matched pair :
\(
\begin{array}{|l|l|l|l|}
\hline & \text { Population interaction } & \text { Species A } & \text { Species B } \\
\hline \text { 1. } & \text { Mutualism } & + & + \\
\hline \text { 2. } & \text { Predation } & + & – \\
\hline \text { 3. } & \text { Parasitism } & – & – \\
\hline \text { 4. } & \text { Commensalism } & + & 0 \\
\hline
\end{array}
\)

The picture shows mutual relationship between the fig tree and the wasp.

I: Many species of fig trees can only be pollinated by their ‘partner’ wasp species and no other species.
II: The female wasp does not derive any benefit from this relationship.

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
\(
\begin{array}{|l|l|}
\hline \text { Assertion (A): } & \begin{array}{l}
\text { Population ecology links ecology to } \\
\text { population genetics and evolution. }
\end{array} \\
\hline \text { Reason (R): } & \begin{array}{l}
\text { It is at the population level that natural } \\
\text { selection operates to evolve the desired } \\
\text { traits. }
\end{array} \\
\hline
\end{array}
\)
In the light of the above statements, choose the most appropriate answer from the options given below :

In a pond, there were 20 lotus plants last year. If through reproduction 4 new lotus plants are added, the number of offspring per lotus per year would be :

If ‘N‘ is the population density at time ‘t‘, then its density at time ‘t+1’ is:
\(
\begin{array}{|l|l|}
\hline \text { I. } & N_{t+1}=N_t+[(B+I)-(D+E)] \\
\hline \text { II. } & \begin{array}{l}
\text { B is a measure of Natality and D is a measure of } \\
\text { Mortality }
\end{array} \\
\hline \text { III. } & \begin{array}{l}
\text { If (B+I) is less than (D+E), the population density } \\
\text { will increase }
\end{array} \\
\hline
\end{array}
\)

All the following are correct about the exponential growth of population except :
\(
\begin{array}{|l|l|l|}
\hline \text { 1. } & \text { It is represented by the equation } \mathrm{dt} / \mathrm{dN}=\mathrm{rN} \\
\hline \text { 2. } & \text { Resources in the habitat are unlimited } \\
\hline \text { 3. } & \text { The rate of natural increase is represented by ” } \mathrm{r} \text { ” } \\
\hline \text { 4. } & \text { In } 1981 \text {, the ‘ } \mathrm{r} \text { ‘ value for human population in India } \\
& \text { was } 0.0205 \\
\hline
\end{array}
\)

In the logistic growth equation given below, the carrying capacity is represented by :
\(
\frac{\mathrm{dN}}{\mathrm{dt}}=\mathrm{rN}\left(\frac{\mathrm{~K}-\mathrm{N}}{\mathrm{~K}}\right)
\)

In the formula for exponential growth \(
(\mathrm{dN} / \mathrm{dt}=\mathrm{rN}),
\) what does ‘ r ‘ stand for ?

A population has more young individuals compared to older individuals. What would be the status of the population after some years ?

Which of the following is/are true for the given equation ?
\(
N_t=N_0 e^{r t}
\)
\(
\begin{array}{|l|l|}
\hline \text { I. } & \text { It is the integral form of exponential growth equation } \\
\hline \text { II. } & \text { The rate of natural increase is represented by “r” } \\
\hline \text { III. } & \text { “e” is the base of natural logarithm [2.71828] } \\
\hline
\end{array}
\)

Darwinian fitness is represented by :

Which of the following organisms does not breed only once in their life time ?

Identify the correct statements :
\(
\begin{array}{|l|l|}
\hline \text { I. } & \begin{array}{l}
\text { Pacific salmon and bamboo breed many times during } \\
\text { their lifetimes. }
\end{array} \\
\hline \text { II. } & \begin{array}{l}
\text { Birds and mammals breed many times during their } \\
\text { lifetimes and produce a small number of large-sized } \\
\text { offspring. }
\end{array} \\
\hline \text { III. } & \begin{array}{l}
\text { Oysters and pelagic fishes produce a large number of } \\
\text { small-sized offspring. }
\end{array} \\
\hline
\end{array}
\)

A population interaction that is detrimental to both species would be :

A population interaction where one species is harmed whereas the other is unaffected is called as :

In broad ecological context, all the following would be considered examples of predation except :

Predators do not :

When certain exotic species are introduced into a geographical area, they become invasive mainly because :

In a field experiment, when all Pisaster starfish were removed from an enclosed intertidal area, the result was :

The most common means of morphological defense in plants against herbivory are :

About what percent of all insects is phytophagus ?

Nicotine, caffeine, quinine and opium produced by plants are actually:

Consider the given statements regarding competition amongst organisms:
I. Only related species can compete for the same resource
II. Competition occurs only when the resources are limiting
The correct statement/s is/are:

In some shallow American lakes, unrelated visiting Flamingoes and resident fishes compete for the common food which is :

A process in which the fitness of one species is significantly lower in the presence of another species, is termed as :

A female fig wasp enters the syconium of a fig, pollinates the flowers, and lays eggs in the ovaries of some of the flowers. The young larvae grow up, eat (and kill) some, but not all, of the seeds, and complete their life cycle. The fig is completely dependent on fig wasps to pollinate its flowers, and the fig wasp requires figs to complete its life cycle. The interaction between figs and fig wasps has aspects of :

Abingdon tortoise in Galapagos islands became extinct within a decade after goats were introduced on the island due to:

The number of correct statements amongst the given is:
Statement I: Parasitism has evolved in many taxonomic groups from plants to higher vertebrates.
Statement II: Many parasites have evolved to be host-specific and both tend to co-evolve.
Statement III: All parasites have only one primary and one intermediate host.
Statement IV: Only a few of the parasites harm their hosts.

Consider the two statements given below :
\(
\begin{array}{|l|l|}
\hline \text { Statement I: } & \begin{array}{l}
\text { The morphological and anatomical features } \\
\text { of endoparasites are greatly simplified but } \\
\text { their reproductive potential is very high. }
\end{array} \\
\hline \text { Statement II: } & \begin{array}{l}
\text { Unlike ectoparasites, endoparasites live } \\
\text { inside the host body at different sites and } \\
\text { their life cycles are more complex. }
\end{array} \\
\hline
\end{array}
\)

A species whose distribution is restricted to a small geographical area because of the presence of a competitively superior species, is found to expand its distributional range dramatically when the competing species is experimentally removed. This is called:

“Competitive Exclusion Principle” may be true if :

One mechanism that promotes co-existence rather than exclusion amongst competing species is :

MacArthur showed that five closely related species of warblers living on the same tree were able to avoid competition and co-exist due to :

The human liver fluke depends on two intermediate hosts that are :

Cuckoos laying their eggs in the nests of crow is an example of :

An orchid growing as an epiphyte on a mango branch is an example of :

All the following relations are examples of commensalism except :

Lichens represent an intimate mutualistic relationship between a fungus and :

In mycorrhiza, the fungi help the plant in :

The fig tree is pollinated by a :

To get pollinated by a bee, the Mediterranean Orchid, Ophrys, employs : 

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
\(
\begin{array}{|l|l|}
\hline \text { Assertion (A): } & \begin{array}{l}
\text { Plant-animal interactions often involve } \\
\text { co-evolution of the mutualists. }
\end{array} \\
\hline \text { Reason (R): } & \begin{array}{l}
\text { The mutually beneficial system should be } \\
\text { safeguarded against ‘cheaters’. }
\end{array} \\
\hline
\end{array}
\)
In the light of the above statements, choose the most appropriate answer from the options given below :

Assertion (A): Population density may be measured in terms of biomass.
Reason (R): Biomass is the only accurate measure for all types of organisms.

Cardiac glycosides in Calotropis :

Which one is NOT a predator in ecological sense ?

Which type of competition occurs when resources are abundant but one species reduces the feeding efficiency of another ?

What does competitive exclusion theory state ?

Which of the following was not usually observed by G.F. Gauss in his studies on interspecific competition ?