GATE — Ecology and Evolution (EY) · India · IITs and IISc on rotation
Original practice questions written to the published syllabus · not past papersWhat biodiversity is, how it is measured, why it is being lost and how it is conserved, from IUCN Red List categories and protected areas to the Kunming-Montreal Global Biodiversity Framework.
In the exams: ICAR AICE subject 71 Unit 2 (whole unit); GATE ES Section 8 (biodiversity); UGC NET Unit 3; UPSC CSE Prelims environment (heavily asked)
GATE — Environmental Science and Engineering (Section 8) and Ecology and Evolution (EY)
Diversity indices (Shannon, Simpson, evenness, Jaccard), alpha/beta/gamma, species-area and island biogeography, effective population size and inbreeding, population growth, Red List criteria; numerical items common.
How our questions for GATE spread across the units of Biodiversity Science & Conservation. Difficulty: 4 easy, 18 medium, 14 hard.
| Measuring biodiversity: alpha, beta, gamma diversity and indices | 10 | |
| Population viability and minimum viable population | 9 | |
| Island biogeography and species-area relationships | 8 | |
| Biogeographic realms and biodiversity hotspots | 4 | |
| Invasive alien species management | 2 | |
| Levels of biodiversity: genetic, species, ecosystem | 1 | |
| Values of biodiversity: use, non-use, intrinsic | 1 | |
| Drivers of biodiversity loss: land-use change, overexploitation, climate, pollution, invasive species | 1 |
Choose an answer, then open the working. Each explanation says why the right answer is right and why the others are not.
With H' = 1.030 for three species, what is Pielou's evenness J' = H'/ln S?
D. 0.94
J' = 1.030/ln 3 = 1.030/1.099 = 0.94. 0.34 divides by 3 instead of ln 3; 3.09 multiplies by 3; 1.03 is H' itself.
What does environmental DNA (eDNA) metabarcoding allow ecologists to do?
C. Detect species from DNA traces in water or soil samples
eDNA metabarcoding sequences DNA shed into the environment to detect which species are present, aiding surveys of fish, amphibians and soil biota. It does not date trees, clone extinct species or edit genomes.
Further reading: Biodiversity monitoring literature
Which is a common criticism of hotspot-based prioritisation?
A. It is biased towards plant endemism
Critics note that hotspots rely on plant endemism and habitat loss, overlooking wilderness, marine areas, low-endemism ecosystems and ecosystem services; complementary approaches such as Key Biodiversity Areas address some gaps. Hotspots are plant-based, include populated areas and are mapped.
Further reading: Hotspot critiques
Which of the five past mass extinctions was the largest?
C. The end-Permian extinction
The end-Permian event (about 252 million years ago) eliminated the largest share of marine and terrestrial species. The end-Cretaceous, which ended the non-avian dinosaurs, is the most famous but not the largest.
Further reading: Primack, Essentials of Conservation Biology
With z ≈ 0.3 in the species-area relationship, a tenfold reduction in area reduces species to roughly what fraction?
D. One half
10^−0.3 ≈ 0.50, giving the rule of thumb that a tenfold area loss halves species. One tenth would assume z = 1.
Further reading: Species-area literature
What was the 'SLOSS' debate about?
D. Whether a single large or several small reserves of equal total area conserve more species
SLOSS asked whether one large reserve or several small ones of the same total area are better; the answer depends on species, habitats and threats. The other expansions are invented.
Further reading: Diamond 1975; Simberloff and Abele 1976
A population with Ne = 50 starts with heterozygosity 0.60. Using Ht = H0(1 − 1/(2Ne))^t, what is heterozygosity after 20 generations?
B. 0.491
Ht = 0.60 × 0.99^20 = 0.60 × 0.818 = 0.491. 0.480 subtracts 20 % linearly; 0.600 ignores drift; 0.401 uses 1/Ne instead of 1/(2Ne).
A population of 200 has a finite rate of increase λ = 0.95 per year. What is its expected size after 10 years?
D. 120
N10 = 200 × 0.95^10 = 200 × 0.599 = 120. 190 applies only one year's decline; 100 subtracts 5 % of 200 ten times; 210 treats λ as growth.
What is the 'extinction vortex'?
D. Mutually reinforcing small-population processes that drive further decline
Gilpin and Soulé described how inbreeding, drift, demographic and environmental stochasticity reinforce each other as populations shrink. The other options are unrelated.
Further reading: Gilpin and Soulé 1986
What is the main practical use of population viability analysis (PVA)?
B. Comparing the effect of management options on extinction risk
PVA models are uncertain, so they are most useful for ranking options such as reducing poaching or translocating animals. They do not give certain dates, replace surveys or classify species automatically (though they inform criterion E).
Further reading: Primack, Essentials of Conservation Biology
Ten here, 36 in the app. The Laisha app has every practice question we have written to GATE 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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