• INDIAN POLITY FOR CIVIL SERVICES EXAMINATIONS
  • Indian Culture for Prelims Preparation
  • Environment and Ecology
  • Economics
  • Geography
  • Science & Technology
  • Indian History
  • Current Affairs

Organism and Population

Organism and its environment

  1. Abiotic Factors
  2. Biotic Factors
  3. Adaptations

Population

  1. Population Attributes
  2. Population growth and Decline
  3. Population Interactions

Ecosystem

  1. Structure and Function
  2. Productivity
  3. Decomposition
  4. Ecological Succession
  5. Energy Flow
  6. Nutrient Cycles
  7. Ecological Pyramids
  8. Ecosystem Services
  • NCERT Biology Class XII- Chapters 13,14
  • NCERT -Science-Class VII- Chapter 7 [Adaptations]
  • NCERT Science-Class X- Chapter 15

[2011 Prelims]

1)In the context of ecosystem productivity, marine upwelling zones are important as they increase the marine productivity  by bringing the  ?

  1.    Decomposer microorganisms to the surface.
  2.    Nutrients to the surface.
  3.    Bottom ­dwelling organisms to the surface.

Which of the statements given above is/are correct  ?

(a)    1 and 2.

(b)    2 only.

(c)    2 and 3.

(d)    3 only.

2)Consider the following :

  1.    Photosynthesis.
  2.    Respiration.
  3.    Decay of organic matter.
  4.    Volcanic action.

Which of the above add carbon dioxide to the carbon cycle  on earth ?

(a)    1 and 4 only .    

(b)    2 and  3 only .

(c)    2, 3 and 4 only.

(d)    1,2,3 and 4 .

[2012 prelims]

1)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?

a) Production of food and water

b) Control of climate and disease

c) Nutrient Cycling and crop pollinator

d) Maintenance of diversity

2)What would happen if phytoplankton of an ocean is completely destroyed for some reason?

  1. The ocean as a carbon sink would be adversely affected.
  2. The food chains in the ocean would be adversely affected.
  3. The density of ocean water would drastically decrease.

Select the correct answer using the codes given below:

a) 1 and 2 only

b) 2 only

c) 3 only

d) 1, 2 and 3

[2013 Prelims]

1)Which one of the following terms describes not only the physical space occupied by an organism, but also its functional role in the community of organisms?

(a) Ecotone

(b) Ecological niche

(c) Habitat

(d) Home range

2) With reference to the food chains in ecosystems, which of the following kinds of organism is / are known as decomposer organism/organisms?

  1. Virus
  2. Fungi
  3. Bacteria

Select the correct answer using the codes given below.

(a) 1 only

(b) 2 and 3 only

(c) 1 and 3 only

(d) 1, 2 and 3

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

(a) insects and fungi

(b) limited sunlight and paucity of nutrients

(c) water limits and fire

(d) None of the above

4)With reference to food chains in ecosystems, consider the following statements :

  1. A food chain illustrates the order in which a chain of organisms feed upon each other.
  1. Food chains are found within the populations of a species.
  2. A food chain illustrates the numbers of each organism which are eaten by others.

Which of the statements given above is / are correct?

(a) 1 only

(b) 1 and 2 only

(c) 1, 2 and 3

(d) None

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

(a) Oceans, lakes, grasslands, mangroves

(b) Mangroves, oceans, grasslands, lakes

(c) Mangroves, grasslands, lakes, oceans

(d) Oceans, mangroves, lakes, grasslands

6)Which of the following adds / add nitrogen to the soil?

  1. Excretion of urea by animals
  2. Burning of coal by man
  3. Death of vegetation

Select the correct answer using the codes given below.

(a) 1 only

(b) 2 and 3 only

(e) 1 and 3 only

(d) 1, 2 and 3

[2014 Prelims]

1)Lichens, which are capable of initiating ecological succession even on a bare rock, are actually a symbiotic association of

(a) algae and bacteria

(b) algae and fungi

(c) bacteria and fungi

(d) fungi and mosses

2)Which of the following adds/add carbon dioxide to the carbon cycle on the planet Earth?

  1. Volcanic action
  2. Respiration
  3. Photosynthesis
  4. Decay of organic matter

Select the correct answer using the code given below.

(a) 1 and 3 only

(b) 2 only

(c) 1, 2 and 4 only

(d) 1, 2, 3 and 4

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

(a) Diatoms-­Crustaceans-­Herrings

(b) Crustaceans-­Diatoms-­Herrings

(c) Diatoms-­Herrings-­Crustaceans

(d) Crustaceans­-Herrings-­Diatoms

4)Consider the following :

  1. Bats
  2. Bears
  3. Rodents

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

(a) 1 and 2 only

(b) 2 only

(c) 1, 2 and 3

(d) Hibernation cannot be observed in any of the above

[2015 Prelims]

1)Which one of the following is the best description of the term ‘ecosystem?

(a) A community of organisms interacting with one another

(b) That part of the Earth which is inhabited by living organisms

(c) A community of organisms together with the environment in which they live

(d) The flora and fauna of a geographical area

[2017 Prelims]

1) 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 answer using the code given below:

(a) 1 only

(b) 2 and 3 only

(c) 1 and 3 only

(d) 1, 2 and 3

Answer: C