Class 12 Biology Chapter 15 Biodiversity and Conservation

Chapter 15 of Class 12 Biology, titled “Biodiversity and Conservation”, highlights the variety of life forms on Earth and emphasizes the urgent need to protect them. The chapter explores the levels, patterns, and importance of biodiversity, as well as the threats it faces due to human activities. It also focuses on strategies for conserving biodiversity, both in situ (within natural habitats) and ex situ (outside natural habitats).

This chapter helps students understand the ecological, economic, and ethical importance of biodiversity and the role they can play in its protection.

What You Will Learn in Chapter 15 – Biodiversity and Conservation

This chapter introduces students to the richness of life on Earth, covering different types of biodiversity and conservation strategies. It also includes national and global efforts to prevent biodiversity loss.

Key Topics Covered:

1. Biodiversity: Definition and Types

  • Biodiversity refers to the variety of life forms found on Earth.

  • Three levels of biodiversity:

    • Genetic diversity: Variety of genes within species.

    • Species diversity: Variety of species in a given region.

    • Ecological diversity: Variety of ecosystems like forests, deserts, wetlands, etc.

2. Biodiversity in India

  • India is one of the 12 mega-diverse countries in the world.

  • Hotspots of biodiversity in India: Western Ghats, Himalayas, Indo-Burma, and Sundaland.

  • High species richness and endemism in India.

3. Patterns of Biodiversity

  • Latitudinal gradient: Biodiversity increases from the poles to the equator.

  • Species-area relationship: Greater the area, higher the number of species.

  • Described by Alexander von Humboldt through a mathematical model.

4. Importance of Biodiversity

  • Ecological role: Maintains ecosystem functions and stability.

  • Economic value: Provides food, fuel, fiber, medicine, and ecosystem services.

  • Ethical and aesthetic values: Respect for all forms of life; inspiration, culture, and heritage.

5. Loss of Biodiversity

  • Major causes of biodiversity loss (HIPPO):

    • H: Habitat loss and fragmentation.

    • I: Invasive species.

    • P: Pollution.

    • P: Population explosion (human).

    • O: Overexploitation of resources.

  • Extinction of species and ecosystem imbalance.

6. Biodiversity Conservation

  • In Situ Conservation:

    • Protecting species in their natural habitat.

    • Includes biosphere reserves, national parks, wildlife sanctuaries, and sacred groves.

  • Ex Situ Conservation:

    • Protecting species outside their natural habitat.

    • Includes zoos, botanical gardens, seed banks, cryopreservation.

7. Global Efforts for Conservation

  • IUCN Red List: Categorizes species based on extinction risk.

  • Convention on Biological Diversity (CBD): International treaty to conserve and share genetic resources.

  • Earth Summit (1992), Rio de Janeiro: Promoted sustainable development and conservation.

Why Use Our NCERT Solutions for Chapter 15?

Our detailed and student-friendly solutions for Chapter 15: Biodiversity and Conservation help simplify complex environmental concepts and enhance understanding with diagrams and real-world examples. These solutions are designed for effective exam preparation and concept clarity.

Highlights of Our Solutions:

  • All NCERT Intext and Exercise questions answered in a simple, precise manner.

  • Definitions, examples, and significance of different levels of biodiversity.

  • Diagrams to explain species-area relationships and conservation models.

  • Practical examples of biodiversity conservation in India and globally.

  • Perfect for CBSE Board, NEET, and other entrance exam preparation.

NCERT Solutions for Chapter 15 – Biodiversity and Conservation

Intext Questions:

  • Detailed explanations of the three levels of biodiversity.

  • Examples and significance of Indian biodiversity hotspots.

  • Real-life applications of conservation strategies.

Exercise Questions (Q.1 to Q.10):

  • Answers to conceptual questions on biodiversity loss and its consequences.

  • Explanation of in situ vs ex situ conservation methods.

  • Discussion on the value of biodiversity—ecological, economic, and ethical.

  • Graph-based questions on species-area relationships.

Download Chapter 15 Solutions PDF – Biodiversity and Conservation

Access a free, downloadable PDF with complete NCERT solutions and diagrams to aid revision and exam success.

What’s Included:

  • Well-structured, easy-to-read solutions.

  • Visual aids for better concept retention.

  • Quick reference glossary of important terms.

Recommended Preparation Tips:

  • Focus on HIPPO – the five major causes of biodiversity loss.

  • Memorize the difference between in situ and ex situ conservation with examples.

  • Study biodiversity hotspots in India and their significance.

  • Understand the species-area relationship and be able to interpret related graphs.

  • Be aware of international treaties like the CBD and the purpose of the IUCN Red List.

Additional Study Resources:

  • Chapter 15 Biology Notes – Biodiversity and Conservation.

  • NCERT Exemplar Problems and Solutions.

  • NEET-level MCQs and assertion-reason questions.

  • Flashcards for biodiversity terms and conservation types.

  • Quick-revision infographic on conservation strategies.

Understanding the Value of Biodiversity

Chapter 15 emphasizes the importance of preserving biodiversity not only for ecological balance but also for the well-being of current and future generations. By studying this chapter, students become more aware of their role as responsible citizens of the planet and the need to protect Earth’s rich biological heritage.

Master this chapter to contribute meaningfully toward a sustainable and biodiverse future.

NCERT Solutions for Class 12 Biology Chapter 15 Biodiversity and Conservation

1. Name the three important components of biodiversity.

Ans: Three components of biodiversity are: (a) Genetic diversity (b) Species diversity (c) Ecological diversity

2. How do ecologists estimate the total number of species present in the world?

Ans: Ecologists estimate the total number of species present in the world by comparing species richness of some exhaustively studied groups between any two regions (tropics, temperate, or polar regions). Species richness, as a measure of diversity, has been used by many ecologists. Species density or the number of species per m² is most commonly used to measure species richness. Species abundance and species proportional abundance based indices are some other alternative approaches to the measurement of diversity.

3. Give three hypotheses for explaining why tropics show greatest levels of species richness.

Ans: (1) The tropical areas have a more stable climate than temperate zones. Local species continue to live in the absence of natural disturbances. (2) Warm temperature and high humidity in most tropical areas provide favourable conditions for the growth and survival of diverse species. (3) Tropical areas receive more solar energy over the year and thus tropical communities are more productive and can support a wide range of species.

4. What is the significance of the slope of regression in a species-area relationship?

Ans: The slope of regression or regression coefficient makes it easier to measure species richness along an area. For a limited area like a country, it gives a constant value of 0.1 to 0.2 irrespective of the taxonomic group or region. It remains amazingly similar for all those small regions. On the contrary, for measuring species-area relationship over large areas like the entire continents, the slope of regression values lie in the range of 0.6 to 1.2.

5. What are the major causes of species losses in a geographical region?

Ans: Species are lost in a geographical region due to natural disturbances like forest fires, famine, drought, and also due to human activities such as overexploitation, habitat destruction, habitat displacement, over-specialization, intensive agriculture, and pollution.

6. How is biodiversity important for ecosystem functioning?

Ans: Biodiversity is important for ecosystem functioning because: (1) It contributes to productivity. (2) It causes more efficient recycling of energy and matter. (3) It provides many alternative pathways for survival under diverse conditions. (4) Rich biodiversity provides alternatives at each trophic level. All organisms are linked in food chains and interact with their abiotic environment to keep the natural cycles going and make ecosystems self-sustaining. The disappearance of any link in a food chain does not significantly affect the ecosystem due to available alternatives.

7. What are sacred groves? What is their role in conservation?

Ans: Sacred forests or sacred groves are forest patches around places of worship which are held in high esteem by tribal communities. These undisturbed forest patches are often surrounded by degraded landscapes. They are found in several parts of India, such as Karnataka, Maharashtra, Rajasthan (Aravalli), Madhya Pradesh (Sarguja, Bastar), Kerala, and Meghalaya. Tribals build temples in these areas and strictly prohibit cutting any vegetation. As a result, many endemic species which are rare or extinct elsewhere thrive here. The Bishnois of Rajasthan protect *Prosopis cineraria* and Black Buck religiously. Some water bodies like Khecheopalri in Sikkim are also considered sacred, preserving their aquatic flora and fauna.

8. Among the ecosystem services are control of floods and soil erosion. How is this achieved by the biotic components of the ecosystem?

Ans: Ecosystem services are benefits provided by ecosystem processes such as purification of air and water, biodiversity, and soil protection. Plants play a vital role in controlling floods and soil erosion. Their roots bind the soil particles firmly, preventing the topsoil from being washed away by wind or water. Additionally, plant roots make the soil porous, allowing water infiltration and reducing surface runoff.

9. The species diversity of plants (22%) is much less than that of animals (72%). What could be the explanation for how animals achieved greater diversification?

Ans: The species diversity of animals is greater than that of plants due to their higher adaptability and dispersal abilities. Most animals possess a nervous system and sensory organs that allow them to respond effectively to environmental changes. Their adaptive behavior enhances survival in diverse conditions, leading to greater speciation. In contrast, plants lack a nervous system and show limited movement and response, resulting in comparatively lower diversification.

10. Can you think of a situation where we deliberately want to make a species extinct? How would you justify it?

Ans: Yes, humans sometimes deliberately aim to eradicate harmful species, such as disease-causing organisms (e.g., poliovirus), to make the world disease-free. This is justified because such organisms are detrimental to human health and are not essential components of ecosystems. Eliminating them does not disrupt ecological balance but rather benefits human society by reducing disease prevalence.