UPSC CAPF Archives

11. The ecological niche of an organism relates to

The ecological niche of an organism relates to

specific habitat of the organism

symbiotic relationship with other organisms

diverse occurrence of a species under different conditions

its interaction with all other organisms

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The ecological niche of an organism is its functional role and position within an ecosystem. It encompasses not just where an organism lives (habitat, A), but also how it interacts with other organisms (biotic interactions) and the environment (abiotic conditions), its resource use, and its position in the food web. While A, B, and C touch upon aspects related to the niche (habitat is part of the environment it occupies, symbiotic relationships are a type of interaction, and occurrence under different conditions relates to the range of its niche), option D, “its interaction with all other organisms,” best represents the biotic aspect of its functional role within the community, which is a crucial component of the ecological niche, especially in the context of Elton’s definition (the animal’s place in the biotic environment). Although a complete definition includes abiotic interactions and resource use, among the given options, D is the most comprehensive in describing the organism’s role within the living part of the ecosystem.

The ecological niche is the functional role or ‘profession’ of an organism in an ecosystem, including its interactions with other organisms and the environment, and its resource use.

Ecological niche is a complex concept with different definitions. Hutchinson defined it as an “n-dimensional hypervolume” representing the range of environmental conditions and resources within which a species can survive and reproduce (fundamental niche) or actually does so in the presence of competitors and predators (realized niche). Elton’s definition focused on the organism’s place and role in the community. Option D aligns well with the role aspect and biotic interactions emphasized in some definitions.

12. Which one of the following is NOT a favourable condition for occurrenc

Which one of the following is NOT a favourable condition for occurrence of a thunderstorm ?

Conditional and convective instability

Adequate supply of moisture in the lower atmosphere

Advection of cold dry air in the lower troposphere and warm moist air in the upper troposphere

A synoptic situation of low level convergence and upper level divergence

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Thunderstorms require unstable atmospheric conditions, a source of moisture, and a lifting mechanism. Statement A describes conditional and convective instability, which is essential for strong vertical air movement. Statement B highlights the need for adequate moisture, which provides latent heat when it condenses, fueling the storm, and also provides the source for precipitation. Statement D describes a synoptic situation that leads to lifting (low-level convergence forces air up) and aids thunderstorm development (upper-level divergence helps remove rising air, maintaining ascent). Statement C describes a stable atmospheric condition where cold, dense air is below warm, less dense air. This stratification inhibits vertical air movement and is unfavourable for thunderstorm development.

Thunderstorms form in unstable atmospheric conditions where warm, moist air rises. A stable atmosphere with cold air below warm air inhibits this process.

The key ingredients for a thunderstorm are moisture, instability, and a lifting mechanism (like fronts, convergence lines, orographic lift, or simple heating). Instability is often provided by a steep vertical temperature lapse rate, where temperature decreases rapidly with height. Advecting cold dry air below warm moist air would create an inversion or stable layer, suppressing convection.

13. Which one of the following statements about the Himalayas is NOT corre

Which one of the following statements about the Himalayas is NOT correct ?

They are young fold mountains

They have geosynclinal rocks

Himalayan frontal faults (HFF) separates Himalaya from Tibet

Indus and Sutlej rivers form antecedent drainage in Himalaya

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Statement A is correct: The Himalayas are formed by the collision of the Indian and Eurasian tectonic plates, making them young fold mountains. Statement B is correct: The rocks that form the Himalayas were deposited in the Tethys Sea, which was a large geosyncline before the mountain building began. Statement D is correct: The Indus and Sutlej rivers originated before the uplift of the Himalayas and maintained their courses by cutting down through the rising mountains, thus forming antecedent drainage patterns. Statement C is incorrect: The Himalayan Frontal Fault (HFF), also known as the Main Frontal Thrust (MFT), is the southernmost major fault zone in the Himalayas, separating the Lesser Himalayas and the Siwalik Hills from the Indo-Gangetic Plain. The boundary between the Himalayas and the Tibetan Plateau is the Indus-Tsangpo Suture Zone (ITSZ).

The Himalayan Frontal Fault separates the Himalayas from the Indo-Gangetic Plain, not from Tibet.

The Himalayas are structured by several major fault zones running roughly parallel to the mountain range. From south to north, these include the Main Frontal Thrust (MFT or HFF), Main Boundary Thrust (MBT), Main Central Thrust (MCT), and the Indus-Tsangpo Suture Zone (ITSZ). The ITSZ marks the collision boundary between the Indian and Eurasian plates and separates the Trans-Himalaya (part of Tibet) from the Great Himalayas.

14. Which of the following statements about the Equatorial region are corr

Which of the following statements about the Equatorial region are correct ?

1. It is a megathermal region
2. It is a sclerophyll region
3. It is a region of high development
4. It is a region of aerial streamlets

Select the correct answer using the code given below :

1 and 4

1 and 2 only

2, 3 and 4

1, 2 and 3

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Statement 1 is correct: Equatorial regions are characterized by consistently high temperatures throughout the year, fitting the definition of a megathermal climate (often represented as Af in Köppen climate classification). Statement 2 is incorrect: Sclerophyll vegetation (hard, leathery leaves adapted to dry summers) is typical of Mediterranean climates, not the humid equatorial climate. Statement 3 is generally incorrect: While there are areas of development, equatorial regions often face geographical challenges (dense forests, climate-related diseases) which historically made widespread high development difficult compared to other regions, though this is a generalization. Statement 4 is likely interpreted as a region with abundant surface drainage or small streams due to very high rainfall, which is characteristic of equatorial rainforests. The term “aerial streamlets” is unusual but in context, refers to the extensive network of small watercourses resulting from high precipitation. Therefore, 1 and 4 are the correct statements.

Equatorial regions have megathermal climates (high temperature, high rainfall) and are characterized by dense drainage networks. They do not have sclerophyll vegetation, which is typical of Mediterranean climates.

Megathermal climates (Köppen Group A) have average temperatures of the coldest month above 18°C. Sclerophyll refers to vegetation with hard leaves, adapted to prevent water loss during prolonged dry periods, common in regions with dry summers. Equatorial regions are characterized by rainforests with dense vegetation and high biodiversity, supported by consistent high temperatures and rainfall. The term “aerial streamlets” is not a standard geographical term, but likely refers to the prevalence of small streams and drainage patterns easily visible, perhaps even from an aerial perspective, due to the high rainfall and terrain.

15. If the product of $n$ positive numbers is unity, then their sum is

If the product of $n$ positive numbers is unity, then their sum is

a positive integer

divisible by $n$

equal to $n + rac{1}{n}$

never less than $n$

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The correct answer is D) never less than n.

Let the n positive numbers be $x_1, x_2, …, x_n$.
We are given that their product is unity: $x_1 \times x_2 \times \dots \times x_n = 1$.
We want to determine the property of their sum: $S = x_1 + x_2 + \dots + x_n$.
According to the Arithmetic Mean – Geometric Mean (AM-GM) inequality, for a set of non-negative numbers, the arithmetic mean is always greater than or equal to the geometric mean. Since the numbers are positive, this inequality applies:
$\frac{x_1 + x_2 + \dots + x_n}{n} \ge \sqrt[n]{x_1 x_2 \dots x_n}$
Substitute the given product into the inequality:
$\frac{S}{n} \ge \sqrt[n]{1}$
$\frac{S}{n} \ge 1$
$S \ge n$
The sum of the n positive numbers whose product is unity is always greater than or equal to n.
Equality holds if and only if all the numbers are equal. If $x_1 = x_2 = \dots = x_n = x$, and their product is 1, then $x^n = 1$. Since they are positive, $x$ must be 1. In this case, the sum is $n \times 1 = n$. If the numbers are not all equal, the sum is strictly greater than n. Therefore, the sum is never less than n.

The AM-GM inequality is a fundamental concept in mathematics often used to find minimum or maximum values or to prove inequalities. It states that for non-negative numbers $a_1, a_2, \dots, a_n$, $\frac{a_1 + a_2 + \dots + a_n}{n} \ge \sqrt[n]{a_1 a_2 \dots a_n}$, with equality holding if and only if $a_1 = a_2 = \dots = a_n$.

16. 5% of income of A is equal to 15% of income of B and 10% income of B i

5% of income of A is equal to 15% of income of B and 10% income of B is equal to 20% of income of C. If the income of C is Rs. 2,000, then what is the total income of A, B and C ?

Rs. 20,000

Rs. 18,000

Rs. 14,000

Rs. 6,000

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The correct answer is B) Rs. 18,000.

We are given the following relationships between the incomes of A, B, and C:
1) 5% of A = 15% of B
(5/100) * A = (15/100) * B
0.05 A = 0.15 B
Divide both sides by 0.05: A = (0.15 / 0.05) B => A = 3B

2) 10% of B = 20% of C
(10/100) * B = (20/100) * C
0.10 B = 0.20 C
Divide both sides by 0.10: B = (0.20 / 0.10) C => B = 2C

We are given the income of C is Rs. 2,000.
Substitute the value of C into the equation for B:
B = 2 * C = 2 * 2000 = Rs. 4,000.

Substitute the value of B into the equation for A:
A = 3 * B = 3 * 4000 = Rs. 12,000.

The total income of A, B, and C is the sum of their individual incomes:
Total Income = A + B + C = 12000 + 4000 + 2000 = Rs. 18,000.

This problem requires setting up and solving a system of linear equations based on the given percentage relationships between the incomes. Starting with the known value (income of C) allows for a straightforward calculation of the other incomes.

17. In an examination, 25% of the candidates failed in Mathematics and 12%

In an examination, 25% of the candidates failed in Mathematics and 12% failed in English. If 10% of the candidates failed in both the subjects and 292 candidates passed in both the subjects, which one of the following is the number of total candidates appeared in the examination ?

300

400

460

500

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The correct answer is B) 400.

Let M be the percentage of candidates who failed in Mathematics, E be the percentage who failed in English, and B be the percentage who failed in both.
Given: M = 25%, E = 12%, B = 10%.
The percentage of candidates who failed in at least one subject is given by the formula:
P(M U E) = P(M) + P(E) – P(M ∩ E)
Percentage failed in at least one subject = 25% + 12% – 10% = 37% – 10% = 27%.
The percentage of candidates who passed in both subjects is the remaining percentage:
Percentage passed in both = 100% – Percentage failed in at least one subject = 100% – 27% = 73%.
We are given that 292 candidates passed in both subjects.
Let T be the total number of candidates.
So, 73% of T = 292
(73 / 100) * T = 292
T = (292 * 100) / 73
T = 29200 / 73
Dividing 29200 by 73: 292 / 73 = 4 (since 73 * 4 = 292).
So, 29200 / 73 = 400.
The total number of candidates is 400.

This problem uses the principle of inclusion-exclusion for calculating the union of two sets (failures in Mathematics and English). The complement of the set of people failing in at least one subject is the set of people passing in both subjects.

18. Study of a single species and the environmental factors in its habitat

Study of a single species and the environmental factors in its habitat is called

Genecology

Synecology

Autecology

Ethology

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The correct answer is C) Autecology.

Autecology is the branch of ecology concerned with the study of the ecological relationships of a single species or population with its environment. It focuses on how an individual species interacts with the biotic and abiotic factors in its habitat, including its adaptations, physiological responses, life cycle, and population dynamics.

A) Genecology is the study of the genetic composition and evolutionary history of plant populations in relation to their ecological environments.
B) Synecology is the study of ecological relationships within biological communities, focusing on the interactions among different species and the structure and function of entire ecosystems.
D) Ethology is the scientific study of animal behavior, usually in natural conditions.

19. NPP (Net Primary Productivity) is highest for

NPP (Net Primary Productivity) is highest for

tropical forests

swamps

reefs

woodland and shrub land

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The correct answer is B) swamps.

Net Primary Productivity (NPP) is the rate at which producers (like plants) accumulate biomass, equal to Gross Primary Productivity minus the rate of respiration. Ecosystems with high light availability, abundant water, warmth, and nutrient-rich conditions tend to have high NPP. Among the given options, tropical forests, swamps, and reefs all have very high NPP per unit area. However, swamps and marshes (a type of wetland) are consistently cited in ecological studies as having among the highest rates of NPP globally, often exceeding tropical forests and reefs due to high nutrient availability from water flow and decomposition under saturated conditions.

Typical NPP values (in g Carbon/m²/year) for these ecosystems can range widely:
* Tropical forests: 1000-3500
* Swamps and Marshes: 800-3500
* Algal beds and reefs: 1000-2500
* Woodland and shrub land: 200-2000
While the ranges overlap, many ecological sources point to swamps/marshes and estuaries as having the absolute highest peak NPP values per unit area.

20. Presence of ozone in the atmosphere is important because it absorbs

Presence of ozone in the atmosphere is important because it absorbs

ultraviolet-A and ultraviolet-B radiations

ultraviolet-B radiations only

infrared-B radiations only

outgoing ultraviolet-B radiations and incoming ultraviolet-A radiations

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The correct answer is A) ultraviolet-A and ultraviolet-B radiations.

Ozone (O₃) in the stratosphere forms the ozone layer, which is crucial for life on Earth because it absorbs a significant portion of the sun’s harmful ultraviolet (UV) radiation before it reaches the surface. While ozone is most effective at absorbing UV-B radiation (wavelengths 280-315 nm), which is particularly harmful to living organisms, it also absorbs a considerable amount of UV-A radiation (315-400 nm) and virtually all UV-C radiation (100-280 nm).

UV-A radiation is less harmful than UV-B but can still cause skin damage and premature aging. UV-B radiation is the primary cause of sunburn, skin cancer, and cataracts. UV-C radiation is the most energetic and harmful but is completely absorbed by the ozone layer and oxygen in the atmosphere. Therefore, the presence of stratospheric ozone is important for absorbing both UV-A and UV-B, reducing their intensity at the Earth’s surface.