Ecology And Functions Of An Ecosystem PYQs — 29 UPSC CSE Previous Year Questions

Question 1

With reference to the planet Earth, consider the following statements : Rain forests produce more oxygen than that produced by oceans. Marine phytoplankton and photosynthetic bacteria produce about 50% of world's oxygen. Well-oxygenated surface water contains several folds higher oxygen than that in atmospheric air. Which of the statements given above is/are correct?

Accepted Answer

B. II only

Question 2

Consider the following : Carabid beetles Centipedes Flies Termites Wasps Parasitoid species are found in how many of the above kind of organisms ?

Accepted Answer

B. Only three

Question 3

Which one of the following shows a unique relationship with an insect that has coevolved with it and that is the only insect that can pollinate this tree ?

Accepted Answer

A. Fig

Question 4

With reference to perfluoroalkyl and polyfluoroalkyl substances (PFAS) that are used in making many consumer products, consider the following statements : PFAS are found to be widespread in drinking water, food and food packaging materials. PFAS are not easily degraded in the environment. Persistent exposure to PFAS can lead to bioaccumulation in animal bodies. Which of the statements given above are correct ?

Accepted Answer

D. 1, 2 and 3

Question 5

"If rainforests and tropical forests are the lungs of the Earth, then surely wetlands function as its kidneys." Which one of the following functions of wetlands best reflects the above statement ?

Accepted Answer

D. Aquatic plants absorb heavy metals and excess nutrients.

Question 6

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

Accepted Answer

A. Ant

Question 7

Consider the following animals: Hedgehog Marmot Pangolin To reduce the chance of being captured by predators, which of the above organisms rolls up/fold up and protects/protect its/their vulnerable parts?

Accepted Answer

D. 1 and 3

Question 8

Which of the following are detritivores? Earthworms Jellyfish Millipedes Seahorses Woodlice Select the correct answer using the code given below.

Accepted Answer

C. 1, 3 and 5 only

Question 9

In case of which one of the following biogeochemical cycles, the weathering of rocks is the main source of release of nutrient to enter the cycle?

Accepted Answer

C. Phosphorus cycle

Question 10

Which of the following have species that can establish symbiotic relationship with other organisms? Cnidarians Fungi Protozoa Select the correct answer using the code given below.

Accepted Answer

D. 1, 2 and 3

Question 11

Which of the following leaf modifications occur(s) in the desert areas to inhibit water loss ? Hard and waxy leaves Tiny leaves Thorns instead of leaves Select the correct answer using the code given below :

Accepted Answer

D. 1, 2 and 3

Question 12

Which of the following statements best describes "carbon fertilization"?

Accepted Answer

A. Increased plant growth due to increased concentration of carbon dioxide in the atmosphere

Question 13

Due to some reasons, if there is a huge fall in the population of species of butterflies, what could be its likely consequence/consequences ? Pollination of some plants could be adversely affected. There could be a drastic increase in the fungal infections of some cultivated plants. It could lead to a fall in the population of some species of wasps, spiders and birds. Select the correct answer using the code given below :

Accepted Answer

C. 1 and 3 only

Question 14

What is/are unique about 'Kharai camel', a breed found in India? It is capable of swimming up to three kilometres in seawater. It survives by grazing on mangroves. It lives in the wild and cannot be domesticated. Select the correct answer using the code given below.

Accepted Answer

A. 1 and 2 only

Question 15

Brominated flame retardants are used in many household products like mattresses and upholstery. Why is there some concern about their use? They are highly resistant to degradation in the environment. They are able to accumulate in humans and animals. Select the correct answer using the code given below.

Accepted Answer

C. Both 1 and 2

Question 16

Which one of the following is the correct sequence of a food chain?

Accepted Answer

A. Diatoms-Crustaceans-Herrings

Question 17

Which of the following adds/add carbon dioxide to the carbon cycle on the planet Earth? Volcanic action Respiration Photosynthesis Decay of organic matter Select the correct answer using the code given below.

Accepted Answer

C. 1, 2 and 4 only

Question 18

Which of the following adds/add nitrogen to the soil? Excretion of urea by animals Burning of coal by man Death of vegetation Select the correct answer using the codes given below.

Accepted Answer

C. 1 and 3 only

Question 19

With reference to the food chains in ecosystems, which of the following kinds of organism is/are known as decomposer organism/organisms? Virus Fungi Bacteria Select the correct answer using the codes given below.

Accepted Answer

B. 2 and 3 only

Question 20

With reference to food chains in ecosystems, consider the following statements: A food chain illustrates the order in which a chain of organisms feed upon each other. Food chains are found within the populations of a species. A food chain illustrates the numbers of each organism which are eaten by others. Which of the statements given above is/are correct?

Accepted Answer

A. 1 only

Question 21

Which of the following leaf modifications occurs/occur in desert areas to inhibit water loss? Hard and waxy leaves Tiny leaves or no leaves Thorns instead of leaves Select the correct answer using the codes given below.

Accepted Answer

D. 1, 2 and 3

Question 22

Which one of the following is the correct sequence of ecosystems in the order of decreasing productivity?

Accepted Answer

C. Mangroves, grasslands, lakes, oceans

Question 23

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

Accepted Answer

C. water limits and fire

Question 24

The Millennium Ecosystem Assessment describes the following major categories of ecosystem services-provisioning, supporting, regulating, preserving and cultural. Which one of the following is supporting service?

Accepted Answer

C. Nutrient cycling and crop pollination

Question 25

Consider the following : Photosynthesis Respiration Decay of organic matter Volcanic action Which of the above add carbon dioxide to the carbon cycle on Earth ?

Accepted Answer

C. 2, 3 and 4 only

Question 26

A pesticide which is a chlorinated hydrocarbon is sprayed on a food crop. The food chain is:
Food crop → Rat → Snake → Hawk.
In this food chain, the highest concentration of the pesticide would accumulate in which one of the following?

Accepted Answer

D. Hawk

Question 27

Epiphytes are plants which. depend on other plants for

Accepted Answer

B. mechanical support

Question 28

Within biological communities, some species are important in determining the ability of a large number of other species to persist in the community. Such species are called

Accepted Answer

A. Keystone species

Question 29

Which one of the following is a useful functional association between fungi and the roots of higher plants?

Accepted Answer

D. Mycorrhiza