UPSC Environment and Ecology – Chapter 1: Ecology and Ecosystems – Basic Concepts (31 MCQs)

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UPSC Environment and Ecology – Chapter 1: Ecology and Ecosystems – Basic Concepts (31 MCQs) – 31 questions, subject: Environment. Every question has the correct answer with a one-line explanation; tap "Show Answer". Free practice for TNPSC, UPSC, SSC, Bank and RRB exams – Shanmugam IAS Academy, Coimbatore.

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1.  

The term "ecology" was coined by:

Correct Answer: D [Ernst Haeckel]

Explanation:

1866.

2.  

Which of the following is an abiotic component of an ecosystem?

Correct Answer: D [Sunlight]

Explanation:

Sunlight is a non-living physical factor; fungi, algae and earthworms are all living (biotic) components.

3.  

The functional role of a species in its community is called its:

Correct Answer: B [niche]

Explanation:

A niche is the functional role of a species: what it eats, when it is active and how it uses space.

4.  

The tendency of a transition zone between two ecosystems to hold more species is called:

Correct Answer: A [edge effect]

Explanation:

Ecotones often hold more species and higher density because species of both neighbouring ecosystems meet there; this is the edge effect.

5.  

"Two species cannot occupy exactly the same niche for long." This is:

Correct Answer: A [Gause's competitive exclusion principle]

Explanation:

Gause's competitive exclusion principle (1934) states that two species cannot share exactly the same niche for long.

6.  

An organism that can tolerate a wide range of temperature is called:

Correct Answer: D [eurythermal]

Explanation:

The prefix eury- means wide, so a eurythermal organism tolerates a wide range of temperature.

7.  

Consider the following statements:

1. Logistic growth gives an S-shaped curve.
2. Carrying capacity is the largest population an environment can support.
3. K-strategists produce many small offspring.

Which of the statements given above are correct?

Correct Answer: C [1 and 2 only]

Explanation:

r-strategists produce many small offspring.

8.  

Which of the following is an example of commensalism?

Correct Answer: D [An orchid growing on a mango tree]

Explanation:

The orchid gains support and light while the mango tree is neither helped nor harmed, a +/0 interaction.

9.  

Penicillium mould inhibiting the growth of bacteria is an example of:

Correct Answer: D [amensalism]

Explanation:

Penicillium inhibits bacteria while itself neither gaining nor losing, the –/0 pattern of amensalism.

10.  

A lichen is an association between:

Correct Answer: B [a fungus and an alga]

Explanation:

A lichen is a mutualistic partnership in which the alga makes food by photosynthesis and the fungus gives shelter and moisture.

11.  

Assertion (A): Trees do not replace grasses in many grasslands even over long periods.

Reason (R): Limited water and recurring fire arrest the succession of grassland to forest.

Correct Answer: A [Both A and R are true, and R is the correct explanation of A]

Explanation:

Limited water and recurring fire stop trees from establishing, so R directly explains why grasses are not replaced.

12.  

Aestivation is:

Correct Answer: C [summer dormancy to avoid heat and drought]

Explanation:

Aestivation is summer dormancy that helps animals such as snails, frogs and lungfish survive heat and drought.

13.  

The usual pioneer species of primary succession on bare rock are:

Correct Answer: C [lichens]

Explanation:

Lichens can grow on bare rock without soil and begin breaking it down, so they are the usual pioneers.

14.  

Consider the following statements:

1. Secondary succession begins where soil is already present.
2. Secondary succession is usually faster than primary succession.
3. A hydrosere begins on dry rock.

Which of the statements given above are correct?

Correct Answer: D [1 and 2 only]

Explanation:

a hydrosere begins in water.

15.  

Arrange the following in chronological order:

1. "Ecosystem" coined by Tansley
2. "Ecology" coined by Haeckel
3. Shelford's law of tolerance
4. Lindeman's trophic-dynamic concept

Select the correct answer:

Correct Answer: C [2-3-1-4]

Explanation:

1866, 1913, 1935, 1942.

16.  

Which of the following lists levels of organisation in increasing order?

Correct Answer: B [Organism, population, community, ecosystem]

Explanation:

Organism, population, community and ecosystem follow the increasing order of ecological organisation shown in Table 1.1.

17.  

The person widely called the "father of ecology in India" is:

Correct Answer: C [Ramdeo Misra]

Explanation:

Ramdeo Misra pioneered ecological research and teaching in India and is widely called the father of ecology in India.

18.  

The Pichavaram mangroves are a good example of:

Correct Answer: B [an ecotone between land and sea]

Explanation:

Pichavaram lies between the Vellar and Kollidam estuaries, where mangroves form a transition zone between land and sea.

19.  

Ecological succession that is driven mainly by outside forces such as fire or flood, rather than by changes the community makes to its own surroundings, is called:

Correct Answer: B [allogenic succession]

Explanation:

allogenic succession is caused by outside forces such as fire or flood (Figure 1.4).

20.  

Microorganisms that thrive at very high temperatures, as in hot springs and deep-sea hydrothermal vents, are called:

Correct Answer: B [extremophiles (thermophiles)]

Explanation:

Extremophiles, here heat-loving thermophiles, thrive at temperatures that would kill most organisms, as in hot springs and hydrothermal vents.

21.  
UPSC Prelims 2024

Consider the following statements:

1. Lions do not have a particular breeding season.
2. Unlike most other big cats, cheetahs do not roar.
3. Unlike male lions, male leopards do not proclaim their territory by scent marking.

Which of the statements given above are correct?

Correct Answer: A [1 and 2 only]

Explanation:

Lions breed at any time of year and cheetahs cannot roar, but male leopards do scent-mark, so only 1 and 2 hold.

22.  
UPSC Prelims 2023

Consider the following statements:

1. Some microorganisms can grow in environments with temperature above the boiling point of water.
2. Some microorganisms can grow in environments with temperature below the freezing point of water.
3. Some microorganisms can grow in a highly acidic environment with a pH below 3.

How many of the above statements are correct?

Correct Answer: C [All three]

Explanation:

Hyperthermophiles grow above 100 °C, psychrophiles below 0 °C and acidophiles below pH 3, so all three statements are true.

23.  
UPSC Prelims 2022

Certain species of which one of the following organisms are well known as cultivators of fungi?

Correct Answer: A [Ant]

Explanation:

Leaf-cutter and other fungus-growing ants raise fungus gardens in their nests and feed on the fungus.

24.  
UPSC Prelims 2021

Which of the following have species that can establish a symbiotic relationship with other organisms?

1. Cnidarians
2. Fungi
3. Protozoa

Select the correct answer using the code given below.

Correct Answer: D [1, 2 and 3]

Explanation:

Corals (cnidarians) host zooxanthellae, fungi form lichens and mycorrhizae, and protozoa live symbiotically in termite guts.

25.  
UPSC Prelims 2021

Consider the following animals:

1. Hedgehog
2. Marmot
3. Pangolin

To reduce the chance of being captured by predators, which of the above organisms rolls up/roll up and protects/protect its/their vulnerable parts?

Correct Answer: D [1 and 3]

Explanation:

Hedgehogs and pangolins roll into a ball to protect their soft parts; marmots escape into burrows instead.

26.  
UPSC Prelims 2021

In the nature, which of the following is/are most likely to be found surviving on a surface without soil?

1. Fern
2. Lichen
3. Moss
4. Mushroom

Select the correct answer using the code given below.

Correct Answer: C [2 and 3]

Explanation:

Lichens and mosses can colonise bare surfaces without soil, whereas ferns and mushrooms need soil or organic matter.

27.  
UPSC Prelims 2017

Due to some reasons, if there is a huge fall in the population of species of butterflies, what could be its likely consequence/consequences?

1. Pollination of some plants could be adversely affected.
2. There could be a drastic increase in the fungal infections of some cultivated plants.
3. It could lead to a fall in the population of some species of wasps, spiders, and birds.

Select the correct one using the code given below:

Correct Answer: C [1 and 3 only]

Explanation:

Butterflies pollinate plants and are food for wasps, spiders and birds; their decline has no clear link to fungal infections.

28.  
UPSC Prelims 2015

Which one of the following is the best description of the term 'ecosystem'?

Correct Answer: C [A community of organisms together with the environment in which they live]

Explanation:

An ecosystem includes both the community of organisms and its abiotic environment, interacting as one functional unit.

29.  
UPSC Prelims 2014

Consider the following:

1. Bats
2. Bears
3. Rodents

The phenomenon of hibernation can be observed in which of the above kinds of animals?

Correct Answer: C [1, 2 and 3]

Explanation:

Hibernation, winter dormancy with very low metabolism, occurs in bats, bears and some rodents.

30.  
UPSC Prelims 2014

Among the following organisms, which one does not belong to the class of the other three?

Correct Answer: A [Crab]

Explanation:

crustacean; the others are arachnids.

31.  
UPSC Prelims 2013

In the grasslands, trees do not replace the grasses as a part of an ecological succession because of

Correct Answer: C [water limits and fire]

Explanation:

Limited water and recurring fire prevent trees from establishing, so grasslands remain arrested at the grass stage.

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