UPSC Prelims 2011 · Question 71 of 100

UPSC Prelims 2011 question on Biodiversity Ecosystem Services

Biodiversity forms the basis for human existence in the following ways:

1. Soil formation

2. Prevention of soil erosion

3. Recycling of waste

4. Pollination of crops

Select the correct answer using the codes given below:

  1. 1, 2 and 3 only
  2. 2, 3 and 4 only
  3. 1 and 4 only
  4. 1, 2, 3 and 4
Show answer

Answer: D. 1, 2, 3 and 4

Verdict

Correct Answer: 1, 2, 3 and 4

All four statements are correct because biodiversity supports soil formation, prevents erosion, recycles waste and enables crop pollination.

Analysis

Biodiversity forms the basis of human existence by providing essential ecosystem services. These services support soil, agriculture, nutrient cycles and overall ecological balance.

Statement by statement

1. Soil formation — Correct

Soil formation depends on living organisms such as bacteria, fungi, lichens, earthworms and plant roots.

They break down rocks and organic matter, helping create fertile soil.

2. Prevention of soil erosion — Correct

Vegetation prevents soil erosion by binding soil through roots.

Plants also reduce the direct impact of wind and rainfall on the soil surface, protecting fertile topsoil.

3. Recycling of waste — Correct

Decomposers such as bacteria and fungi break down dead plants, animals and organic waste.

This recycles nutrients like nitrogen and phosphorus back into the ecosystem.

4. Pollination of crops — Correct

Many crops depend on pollinators such as bees, butterflies, birds and bats.

Pollination supports agricultural productivity and food security.

Extra UPSC info

* Biodiversity provides ecosystem services essential for human survival.

* Soil formation and nutrient cycling are supporting services.

* Pollination and erosion control are regulating services.

* Food, water, timber and medicinal plants are provisioning services.

* Recreation, tourism and spiritual values are cultural services.

* Loss of biodiversity can affect food security, soil fertility and ecological stability.

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