CBSE Class 12 Biology Case-Based Questions – Biodiversity and Conservation (NCERT Based)

Unit V: Ecology and Environment | Chapter 15: Biodiversity and Conservation

CBSE Class 12 Biology Chapter 15 Case-Based Questions – Biodiversity and Conservation (NCERT)

Course & Examination Details

• Course: CBSE Class 12 Biology
• Unit: Unit V – Ecology and Environment
• Chapter: Chapter 15 – Biodiversity and Conservation
• Board: Central Board of Secondary Education (CBSE)
• Syllabus Base: Strictly as per NCERT Textbook
• Exam Relevance: CBSE Class 12 Board Exams (Competency-Based / Case-Based Questions)

Case-Based Questions with Answers

(Prepared strictly as per NCERT concepts and CBSE competency-based assessment pattern)

Section A: Biodiversity and Its Levels (Case 1–5)

Case 1

A forest region contains multiple species of plants, insects, birds, mammals, and microorganisms.

Q1. Which level of biodiversity is represented here?
Ans: Species diversity.

Q2. Why is this biodiversity important for ecosystem stability?
Ans: Higher species diversity increases ecosystem resilience and stability.

Case 2

Different varieties of rice show varying resistance to drought and pests.

Q1. Identify the level of biodiversity involved.
Ans: Genetic diversity.

Q2. How does this diversity help farmers?
Ans: It ensures crop survival under changing environmental conditions.

Case 3

A region includes forests, grasslands, wetlands, and deserts.

Q1. Which level of biodiversity is shown?
Ans: Ecosystem diversity.

Q2. Why is ecosystem diversity important?
Ans: Different ecosystems perform unique ecological functions.

Case 4

Tropical rainforests show greater species richness than polar regions.

Q1. Which biodiversity pattern explains this?
Ans: Latitudinal gradient.

Q2. Give one reason for this pattern.
Ans: Stable climate and high productivity in tropics.

Case 5

India supports a large number of endemic species despite small land area.

Q1. Why is India termed a mega-diverse country?
Ans: It harbors nearly 8% of global species diversity.

Q2. Name one Indian biodiversity hotspot.
Ans: Western Ghats.

Section B: Patterns and Importance of Biodiversity (Case 6–10)

Case 6

A larger forest patch supports more species than a small forest fragment.

Q1. Which ecological relationship explains this?
Ans: Species–area relationship.

Q2. Write the general form of this relationship.
Ans: S = CAᶻ.

Case 7

An ecosystem with high biodiversity shows better recovery after a disturbance.

Q1. What property of biodiversity is responsible?
Ans: Ecosystem resilience.

Q2. How does biodiversity improve resilience?
Ans: Functional redundancy allows quick recovery.

Case 8

Several life-saving drugs are derived from plants and microbes.

Q1. Which importance of biodiversity is highlighted?
Ans: Economic and medicinal importance.

Q2. Why should such biodiversity be conserved?
Ans: It provides potential future medicines.

Case 9

A nature reserve attracts tourists and supports local culture.

Q1. Which value of biodiversity is shown here?
Ans: Aesthetic and cultural value.

Q2. How does this benefit society?
Ans: It promotes recreation and eco-tourism.

Case 10

Pollinators decline in an agricultural area, reducing crop yield.

Q1. Which ecosystem service is affected?
Ans: Pollination service.

Q2. How is biodiversity linked to agriculture?
Ans: It supports pollination and pest control.

Section C: Loss of Biodiversity (Case 11–17)

Case 11

A forest is cleared for urban development.

Q1. Identify the major cause of biodiversity loss.
Ans: Habitat loss.

Q2. Why is it considered the most serious cause?
Ans: It destroys natural living spaces.

Case 12

A large forest is divided into smaller patches by roads.

Q1. What is this process called?
Ans: Habitat fragmentation.

Q2. How does it affect species survival?
Ans: It isolates populations and reduces genetic diversity.

Case 13

Excessive fishing has reduced fish populations drastically.

Q1. Name the cause of biodiversity loss involved.
Ans: Over-exploitation.

Q2. What is its long-term effect?
Ans: Population decline and extinction.

Case 14

An introduced plant species spreads rapidly and replaces native plants.

Q1. What phenomenon is this?
Ans: Alien species invasion.

Q2. Name one invasive species in India.
Ans: Lantana camara.

Case 15

A parasite species disappears after extinction of its host.

Q1. Identify this type of extinction.
Ans: Co-extinction.

Q2. Why does it occur?
Ans: Dependent species cannot survive without hosts.

Case 16

Extinction rates today are much higher than natural rates.

Q1. How much higher is the current extinction rate?
Ans: 100–1000 times higher.

Q2. What is the main reason?
Ans: Human activities.

Case 17

A species found only in a small region disappears due to habitat destruction.

Q1. What type of species is this?
Ans: Endemic species.

Q2. Why are such species more vulnerable?
Ans: Restricted distribution.

Section D: Biodiversity Conservation (Case 18–25)

Case 18

A national park protects wildlife without human interference.

Q1. Which conservation method is used?
Ans: In situ conservation.

Q2. Name one advantage of this method.
Ans: Conserves entire ecosystems.

Case 19

Rare animals are bred in controlled environments.

Q1. Which conservation method is this?
Ans: Ex situ conservation.

Q2. Name one ex situ facility.
Ans: Zoological park.

Case 20

Seeds of crop plants are preserved for future use.

Q1. What conservation technique is used?
Ans: Seed banks.

Q2. Why is it important?
Ans: Preserves genetic diversity.

Case 21

A biosphere reserve allows limited human activity.

Q1. Why are such reserves important?
Ans: They promote conservation with sustainable use.

Q2. Which conservation type do they represent?
Ans: In situ conservation.

Case 22

Critically endangered species are protected from poaching.

Q1. Which conservation approach helps immediately?
Ans: Ex situ conservation.

Q2. Why is it necessary?
Ans: Prevents immediate extinction.

Case 23

A forest ecosystem is protected to maintain natural evolution.

Q1. Which conservation method allows evolution?
Ans: In situ conservation.

Q2. Why is evolution important?
Ans: It helps species adapt naturally.

Case 24

Hotspots are given conservation priority worldwide.

Q1. Why are hotspots important?
Ans: They have high endemism and threat levels.

Q2. Name one Indian hotspot.
Ans: Western Ghats.

Case 25

Citizens participate in tree plantation and wildlife protection.

Q1. How do individuals contribute to conservation?
Ans: Through sustainable practices and awareness.

Q2. What is the ultimate goal of conservation?
Ans: Ecological balance and sustainability.

CBSE Exam Note

These case-based questions strengthen analytical thinking, application of concepts, and competency-based learning, strictly aligned with NCERT Chapter 15 – Biodiversity and Conservation and the CBSE board exam pattern.