NEET Bio — Biodiversity and Conservation

Chapter Overview & Weightage

Biodiversity and Conservation is one of the most reliable scoring chapters in NEET Biology. It’s information-dense but conceptually straightforward — pure memorisation pays off. Expect 2–3 questions per NEET paper from this chapter, contributing 8–12 marks.

NEET Weightage (Year-by-Year)

Year	Questions	Marks	Topics
2024	3	12	Hotspots, IUCN Red List, in-situ conservation
2023	2	8	Species-area relationship, ex-situ conservation
2022	3	12	Loss causes, biodiversity types, biospheres
2021	2	8	Endemic species, hotspots in India

Key Concepts You Must Know

Three levels of biodiversity:

Genetic diversity (within a species)
Species diversity (number of species)
Ecological/Ecosystem diversity (different ecosystems)

Patterns of biodiversity:

Latitudinal gradient: tropics > temperate > polar
Species-area relationship: $\log S = \log C + Z \log A$ , where $Z =$ slope (0.1–0.2 for small areas, 0.6–1.2 for large areas/continents)

Importance of biodiversity:

Narrowly utilitarian (food, medicines, fibre)
Broadly utilitarian (ecosystem services — pollination, climate regulation)
Ethical (intrinsic value)

Loss of biodiversity — “evil quartet”:

Habitat loss and fragmentation
Over-exploitation
Alien species invasion
Co-extinctions

Biodiversity hotspots: 36 globally. India has 4: Western Ghats and Sri Lanka, Indo-Burma, Himalayas, Sundaland. (Note: NCERT mentions India in 4 hotspots, three of which are entirely or partially in India.)

Conservation:

In-situ: in natural habitat (national parks, sanctuaries, biosphere reserves)
Ex-situ: outside natural habitat (zoos, botanical gardens, seed banks, gene banks)

Sacred groves: community-protected forests in India (Khasi hills, Aravalli, Western Ghats). Important conservation tradition.

Important Numerical Facts

$\log S = \log C + Z \log A$

Where $S$ = species richness, $A$ = area, $C$ = constant, $Z$ = slope.

Small areas: $Z \approx 0.1$ to $0.2$
Large areas (continents): $Z \approx 0.6$ to $1.2$

Plotted on log-log axes, the species-area relation gives a straight line.

Total described species globally: ~1.7-1.8 million
Estimated total species: 7-10 million (some estimates up to 20 million)
India’s share: 8.1% of world species
Plants: ~22% of world’s plant species in India
Endemism in India: ~33% of plants and animals are endemic
Hotspots in India: 4 (Western Ghats-Sri Lanka, Indo-Burma, Himalaya, Sundaland)

Solved Previous Year Questions

PYQ 1 — NEET 2024

Which of the following is NOT a biodiversity hotspot in India? (a) Western Ghats (b) Indo-Burma (c) Himalaya (d) Eastern Ghats

Answer: (d) Eastern Ghats. The four Indian hotspots are Western Ghats-Sri Lanka, Indo-Burma, Himalaya, and Sundaland.

PYQ 2 — NEET 2023

The species-area relationship is described by: $\log S = \log C + Z \log A$

Slope $Z$ is steeper for very large areas (continents) — typically 0.6 to 1.2 — and shallower (0.1 to 0.2) for small ecosystems within a continent. The relationship was originally described by Alexander von Humboldt.

PYQ 3 — NEET 2022

Which of the following is an example of ex-situ conservation? (a) National Park (b) Biosphere Reserve (c) Botanical Garden (d) Wildlife Sanctuary

Answer: (c) Botanical Garden. Plants/animals conserved away from their natural habitat. National parks, reserves, and sanctuaries are in-situ.

Difficulty Distribution

Difficulty	%	Sub-topics
Easy	50%	Definitions, hotspot names, conservation types
Medium	40%	Patterns, species-area, IUCN categories
Hard	10%	Quantitative species-area, complex case-studies

Expert Strategy

Week 1 — Lock in the basics. Three levels of biodiversity, evil quartet, three importance categories. Memorise the four Indian hotspots.

Week 2 — Patterns and conservation. Species-area equation (with $Z$ values). In-situ vs ex-situ examples (3-4 of each).

Week 3 — IUCN Red List categories. Extinct, Extinct in Wild, Critically Endangered, Endangered, Vulnerable, Near Threatened, Least Concern. Plus examples for each.

NCERT verbatim approach: NEET Biology is famously “NCERT verbatim”. Every fact, every list, every name in NCERT can become an MCQ. Read NCERT chapters on Biodiversity slowly, with a highlighter.

Common Traps

Trap 1: Confusing hotspot names.

The four Indian hotspots are Western Ghats-Sri Lanka, Indo-Burma, Himalaya, Sundaland. Eastern Ghats is NOT a hotspot. Aravallis are NOT a hotspot.

Trap 2: In-situ vs ex-situ examples.

National Parks, Sanctuaries, Biosphere Reserves = in-situ. Zoos, Botanical Gardens, Seed Banks = ex-situ. Sacred Groves are in-situ (community-managed).

Trap 3: $Z$ value range.

Small areas (within a region) have small $Z$ (0.1–0.2). Large areas (continents) have larger $Z$ (0.6–1.2). NEET frequently asks the direction of this difference.

Trap 4: Levels of biodiversity confusion.

The three levels are genetic, species, and ecosystem (or ecological). Some students answer “phylum” or “kingdom” — those are taxonomic ranks, not biodiversity levels.

Trap 5: Latitudinal gradient direction.

Species richness decreases from tropics to poles. Tropical regions are most diverse. The direction is reversed for some specific groups (e.g., aphids, certain marine taxa) but those are exceptions NEET rarely asks.