CUET-PG — Environmental Sciences · India · National Testing Agency
Original practice questions written to the published syllabus · not past papersHow organisms, populations, communities and ecosystems work: energy flow, productivity, nutrient cycles, succession and population dynamics. Every sustainability argument eventually rests on this subject.
In the exams: GATE ES Section 8 (ecology and ecosystems); ICAR AICE subject 71 Unit 1; UGC NET Environmental Sciences Unit 3 (environmental biology); GATE EY core
CUET-UG Environmental Studies, CUET-PG and ICAR AIEEA-PG Environmental Science
Definitions and examples: levels of organisation, producers and consumers, food chains, pyramids, the nitrogen cycle and its bacteria, interactions, succession stages and biomes, with simple calculations.
How our questions for CUET-PG spread across the units of Ecology & Ecosystem Science. Difficulty: 21 easy, 64 medium, 0 hard.
| Community structure, diversity and dominance | 8 | |
| Population growth: exponential, logistic, r- and K-selection | 7 | |
| Biomes of the world: forest, grassland, desert, tundra, aquatic | 7 | |
| Habitat, niche and the competitive exclusion principle | 6 | |
| Population characteristics: density, natality, mortality, age structure | 6 | |
| Species interactions: competition, predation, mutualism, parasitism | 6 | |
| Ecological succession: primary, secondary, climax concepts | 6 | |
| Ecosystem structure and function; trophic levels, food chains and webs | 6 | |
| Energy flow, ecological efficiency and ecological pyramids | 6 | |
| Primary and secondary productivity | 6 | |
| Biogeochemical cycles: carbon, nitrogen, phosphorus, sulphur, water | 6 | |
| Levels of ecological organisation; autecology and synecology | 5 | |
| Agroecosystems compared with natural ecosystems | 5 | |
| Stability, resistance and resilience of ecosystems | 5 |
Choose an answer, then open the working. Each explanation says why the right answer is right and why the others are not.
In ecology, the niche of a species is best described as its
D. its functional role and resources used
The niche is the species' 'profession'; the habitat is its 'address'.
Further reading: See the manual sources: standard ecology textbooks (Odum, Begon et al., Krebs) and the original studies named in the explanation
For logistic growth dN/dt = rN(1 − N/K) with r = 0.4 per year and K = 1000, what is the growth rate when N = 500?
D. 100 per year
dN/dt = 0.4 × 500 × (1 − 0.5) = 100 per year, the maximum, since it occurs at K/2.
Further reading: See the manual sources: standard ecology textbooks (Odum, Begon et al., Krebs) and the original studies named in the explanation
An orchid growing on a tree branch, gaining support without harming the tree, shows
C. commensalism
Epiphytes benefit (+) while the host is unaffected (0): commensalism.
Further reading: See the manual sources: standard ecology textbooks (Odum, Begon et al., Krebs) and the original studies named in the explanation
Mycorrhizal associations benefit plants chiefly by
D. better phosphorus and water uptake for plant sugars
Mycorrhizal fungi extend root reach, especially for phosphorus and water; nitrogen fixation is by rhizobia and others.
Further reading: See the manual sources: standard ecology textbooks (Odum, Begon et al., Krebs) and the original studies named in the explanation
Succession on an abandoned crop field, where soil is already present, is
C. secondary succession
Secondary succession starts where soil remains after disturbance; primary succession starts without soil.
Further reading: See the manual sources: standard ecology textbooks (Odum, Begon et al., Krebs) and the original studies named in the explanation
Biomagnification refers to
A. toxins concentrating up food chains
Persistent, fat-soluble pollutants such as DDT and methylmercury concentrate up food chains.
Further reading: See the manual sources: standard ecology textbooks (Odum, Begon et al., Krebs) and the original studies named in the explanation
A single large tree supporting thousands of insects gives which type of pyramid of numbers?
B. Inverted
One producer supports many herbivores, so the number pyramid is inverted at its base.
Further reading: See the manual sources: standard ecology textbooks (Odum, Begon et al., Krebs) and the original studies named in the explanation
Which biome has permafrost, a short growing season and vegetation of mosses, lichens and dwarf shrubs?
B. Tundra
Arctic tundra has permafrost and low vegetation; savannas and forests are warmer.
Further reading: See the manual sources: standard ecology textbooks (Odum, Begon et al., Krebs) and the original studies named in the explanation
How many biogeographic zones did Rodgers and Panwar (1988) recognise for India?
D. Ten
Ten zones: Trans-Himalaya, Himalaya, Desert, Semi-arid, Western Ghats, Deccan, Gangetic Plain, North-East, Coasts and Islands.
Further reading: See the manual sources: standard ecology textbooks (Odum, Begon et al., Krebs) and the original studies named in the explanation
What does the insurance hypothesis propose?
C. Species respond differently, so diversity sustains function
Functional redundancy and response diversity buffer ecosystems against fluctuations.
Further reading: See the manual sources: standard ecology textbooks (Odum, Begon et al., Krebs) and the original studies named in the explanation
Ten here, 85 in the app. The Laisha app has every practice question we have written to CUET-PG in this subject, marked as you go, with timed papers, a jump-to-unanswered list and a certificate when you pass at 70 per cent.
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