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This chapter is all that you need to know about biodiversity and conservation for Class 11 students. The Notes on NCERT Class 11 Geography Chapter 14: Biodiversity and Conservation provides a clear overview of biodiversity, its levels, importance, threats and steps for conservation. The notes discussed here will simplify complex concepts into easy-to-understand language, especially for students who are looking for exam preparation and quick revision on this chapter. You can also download the free PDF for effective exam preparation.
Contents
- 1 Introduction
- 2 What is Biodiversity?
- 3 Levels of Biodiversity
- 4 Importance of Biodiversity
- 5 Loss of Biodiversity
- 6 Categories of Threatened Species
- 7 Conservation of Biodiversity
- 8 Important Definitions in NCERT Notes Class 11 Geography Fundamentals of Physical Geography Chapter 14: Biodiversity and Conservation
- 9 FAQs
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Introduction
Biodiversity is the result of 2.5–3.5 billion years of evolution and is defined as the variety of organisms within a specified geographic region, including plants, animals, microorganisms, their genes, and the ecosystems they form. It is influenced by the weathering mantle, driven by solar energy and water, which supports diverse vegetation and biodiversity. Before humans, Earth had higher biodiversity, but human activities have caused a rapid decline, with species extinction due to overuse. Estimates suggest 2–100 million species exist globally, with 10 million being the best estimate. Tropical forests are particularly rich in biodiversity, which is unevenly distributed, being richest in the tropics and decreasing toward polar regions.
What is Biodiversity?
Biodiversity, a combination of “bio” (life) and “diversity” (variety), refers to the number and variety of organisms in a specific area. It encompasses variability within and between species and ecosystems. Biodiversity is a dynamic system, constantly evolving, with an average species half-life of 1–4 million years; 99% of species that ever lived are extinct. It is a critical component of Earth’s living wealth, shaped by millions of years of evolutionary history.
Also Read:
- NCERT Class 6 Geography: Chapter 3 Motions of the Earth
- NCERT Notes Class 11 Geography Fundamentals of Physical Geography Chapter 9: Atmospheric Circulation and Weather Systems (Free PDF)
Levels of Biodiversity
Biodiversity is categorised into three levels. These levels are mentioned below:
- Genetic Diversity: Variation of genes within a species, essential for healthy breeding and population survival. For example, humans (Homo sapiens) show diversity in traits like height and physical appearance due to genetic variation.
- Species Diversity: The variety and abundance of species in a defined area, measured by richness, abundance, and types. Areas with high species diversity are called hotspots.
- Ecosystem Diversity: The variety of ecosystem types, habitats, and ecological processes. Ecosystem boundaries are complex and not rigidly defined.
Importance of Biodiversity
Biodiversity contributes to human culture and shapes nature at the genetic, species, and ecological levels. It plays three key roles, which are mentioned below:
- Ecological Role: Every species contributes to ecosystem functions, such as capturing energy, cycling nutrients, decomposing organic matter, fixing atmospheric gases, and regulating climate. Diverse ecosystems are more resilient to environmental changes and more productive, ensuring stability and human survival.
- Economic Role: Biodiversity provides resources like food crops, livestock, forests, fish, and medicinal products. Crop diversity (agro-biodiversity) is vital for food security, while overexploitation of biological resources leads to conflicts over resource division.
- Scientific Role: Each species offers insights into life’s evolution and ecosystem functioning. Understanding biodiversity helps us learn how life sustains itself, emphasising our ethical responsibility to protect all species’ right to exist.
Loss of Biodiversity
Human population growth has accelerated resource consumption, leading to habitat destruction and species loss. Tropical regions, which host 50% of Earth’s species despite covering only one-fourth of its area, face severe threats from deforestation and overexploitation. Other causes of biodiversity loss include:
- Natural Calamities: Earthquakes, floods, volcanic eruptions, forest fires, and droughts damage flora and fauna.
- Pollution: Pesticides, hydrocarbons, and toxic heavy metals harm sensitive species.
- Exotic Species: Introduced species disrupt natural ecosystems, causing extensive damage.
- Poaching: Illegal hunting of animals like tigers, elephants, and rhinos for their parts has endangered many species.
Categories of Threatened Species
The International Union for Conservation of Nature and Natural Resources (IUCN) classifies threatened species into three categories:
- Endangered Species: Species in danger of extinction, listed in the IUCN Red List.
- Vulnerable Species: Species likely to become endangered if threats continue.
- Rare Species: Species with small populations, confined to limited areas or thinly scattered.
Also Read:
- NCERT Class 6 Geography: Chapter 5 Major Domains of the Earth
- NCERT Notes Class 11 Geography Fundamentals of Geography Chapter 3 Interior of the Earth (Free PDF)
Conservation of Biodiversity
Biodiversity is vital for human existence, as all life forms are interlinked, and the loss of one can disrupt others. Conservation requires sustainable practices and community involvement. The Government of India, along with 155 other nations, signed the Convention on Biological Diversity at the 1992 Earth Summit in Rio de Janeiro. The World Conservation Strategy suggests:
- Preserving endangered species.
- Preventing extinction through proper planning and management.
- Preserving varieties of food crops, forage plants, timber trees, livestock, and their wild relatives.
- Protecting habitats of wild relatives.
- Safeguarding habitats for feeding, breeding, resting, and nursing.
- Regulating international trade in wild plants and animals.
The Government of India passed the Wildlife (Protection) Act, 1972, establishing national parks, sanctuaries, and biosphere reserves. Mega diversity centres, like India, Brazil, and Indonesia, host significant species diversity. Biodiversity hotspots, areas with high species richness and vulnerability, are prioritised for conservation, such as Madagascar, where 85% of species are unique.
Important Definitions in NCERT Notes Class 11 Geography Fundamentals of Physical Geography Chapter 14: Biodiversity and Conservation
- Biodiversity: The variety of organisms, including plants, animals, microorganisms, their genes, and ecosystems, within a specific region.
- Genetic Diversity: Variation of genes within a species, crucial for healthy breeding.
- Species Diversity: The variety and abundance of species in an area, measured by richness and types.
- Ecosystem Diversity: The variety of ecosystem types, habitats, and ecological processes.
- Hotspots: Areas with high species diversity and vulnerability, prioritised for conservation.
- Endangered Species: Species at risk of extinction, listed in the IUCN Red List.
- Vulnerable Species: Species likely to become endangered if threats persist.
- Rare Species: Species with small populations, limited to specific areas or thinly scattered.
- Mega Diversity Centres: Countries like India and Brazil with a large share of global species diversity.
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FAQs
Biodiversity is the variety of organisms, including plants, animals, microorganisms, their genes, and ecosystems, within a specific geographic region.
Biodiversity loss is caused by human overexploitation, deforestation, natural calamities, pollution, exotic species, and poaching.
Biodiversity conservation is crucial for ecosystem stability, human survival, economic resources, and scientific understanding, ensuring sustainable development and species survival.
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