SSC CGL 2024 Tier-I · 13 September 2024, Shift 1 · General Awareness · Question 8 of 100

Text as printed on a candidate's response sheet for this shift; answer per SSC's tentative key as marked on that sheet. Solution last reviewed 10 September 2026.

Where this paper and its answers come from

SSC does not publish CGL question papers or a public answer key. The questions and options here are reproduced as printed on a candidate's own response sheet for this shift — the Commission's text, unchanged. Each answer is SSC's tentative key as marked on that sheet; SSC allowed challenges to it and never publishes a final key. The solutions are written by UnlockIAS.

Which of the following is a man-made ecosystem?

(a)Forest
(b)Aquarium
(c)Grassland
(d)Dessert

Answer

Why

Correct — B. An aquarium is assembled by people. Someone chooses the species, sets the boundary of the tank, and supplies the light, the oxygen, the food and the filtration.

That is what makes an ecosystem man-made: its structure and its energy inputs come from human decisions rather than from climate and soil.

The test is what happens if people walk away. An aquarium collapses within days. A forest, a grassland and a desert carry on. Option (b).

Why the others are wrong

(a)
Forest — A forest is the standard example of a natural ecosystem. Its species mix is set by rainfall, temperature and soil, and it regenerates without anyone tending it.
(c)
Grassland — Grassland forms naturally where rainfall is too low to support trees and too high for desert. A managed pasture is human work, but grassland as an ecosystem type is not.
(d)
Dessert — The paper prints 'Dessert' for desert. Either way it is a natural ecosystem, shaped by low rainfall and a wide temperature range rather than by human hands.

Concept

Ecosystems are sorted by origin into natural and man-made, also called artificial.

Natural ecosystems — forest, grassland, desert, pond, lake, ocean — organise themselves. Man-made ecosystems — aquarium, crop field, garden, orchard, reservoir — are created and maintained for a human purpose.

Artificial ecosystems share a signature: they hold far fewer species, they are usually dominated by one or two chosen ones, and they depend on a continuing human subsidy of energy and nutrients. Remove the subsidy and they do not persist.

The stem wants origin, not size. A tank is small and a forest is large, but that is not what separates them — a reservoir is enormous and still man-made.

Key facts

Man-made ecosystems are created and maintained by humans for a human purpose.
An aquarium depends on human-supplied food, light, aeration and filtration.
Crop fields, gardens, orchards and reservoirs are also man-made ecosystems.
Artificial ecosystems generally carry lower species diversity than natural ones.

Study next

Biotic and abiotic components of an ecosystemProducers, consumers and decomposers in a food chainEnergy flow through trophic levels and the ten per cent law

Common traps

Treating a pond as man-made because it is small, when a natural pond is not
Reading the paper's spelling 'Dessert' as something other than desert

Ecosystem items are single-line definitions rather than reasoning problems. The basic classification of ecosystems is asked immediately afterwards on 13 Sep 2024, 09:00, GA Q.9, and the count of India's biosphere reserves on 12 Sep 2024, 16:00, GA Q.20.

Related PYQs

No directly related past PYQ was found.