Chapter 14 – Biodiversity and Conservation | CBSE Notes

GEOGRAPHY | CLASS XI | NCERT

Book: Fundamentals of Physical Geography | Chapter 14

Biodiversity and Conservation

⭐ Topper Level 💬 Easy Language 📌 Point-Wise 🌿 Last Chapter

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1. Learning Objectives

After reading these notes, you will be able to:

Understand what biodiversity is and its three levels — Genetic, Species and Ecosystem diversity.

Know the importance of biodiversity — Ecological, Economic and Scientific roles.

Understand the causes for loss of biodiversity and the three IUCN categories of threatened species.

Know about conservation measures — biodiversity hotspots, mega diversity centres, Earth Summit and Wild Life Protection Act.

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2. What is Biodiversity?

Biodiversity is a combination of two words — Bio (life) and diversity (variety). In simple terms, biodiversity is the number and variety of organisms found within a specified geographic region. It refers to the varieties of plants, animals and micro-organisms, the genes they contain and the ecosystems they form. Biodiversity is our living wealth.

2.5–3.5 Billion

Years of evolution that has resulted in today’s biodiversity

10 Million

Best estimate of number of species on Earth (range: 2 million to 100 million)

99%

Of species that have ever lived on Earth are today extinct

1–4 Million

Average half-life of a species (in years)

📌 Key Facts about Biodiversity

Biodiversity is not found evenly on the Earth — it is consistently richer in the tropics. As one approaches the polar regions, one finds larger and larger populations of fewer and fewer species. The basic cause for biodiversity is the input of solar energy and water. Areas rich in these inputs are the areas of wide spectrum of biodiversity. Tropical forests are very rich in biodiversity. About 40% of fresh water fishes from South America are not classified yet — new species are regularly discovered.

🔬 Three Levels of Biodiversity

🌿 Mind Map — Levels of Biodiversity

Biodiversity

🧬 Genetic Diversity
Variation of genes
within species
(e.g. human differences)

🐾 Species Diversity
Variety of species
in a defined area
Hotspots

🌍 Ecosystem Diversity
Diversity of habitats
and ecological
processes

🧬 1. Genetic Diversity

Genes are the basic building blocks of various life forms. Genetic biodiversity refers to the variation of genes within species. Groups of individual organisms having certain similarities in physical characteristics are called species. Human beings genetically belong to the homo sapiens group but differ in height, colour, physical appearance — due to genetic diversity. This diversity is essential for healthy breeding of population of species.

🐾 2. Species Diversity

Refers to the variety of species. It relates to the number of species in a defined area. The diversity of species can be measured through its richness, abundance and types. Some areas are more rich in species than others. Areas rich in species diversity are called hotspots of diversity.

🌍 3. Ecosystem Diversity

The broad differences between ecosystem types and the diversity of habitats and ecological processes occurring within each ecosystem type constitute ecosystem diversity. The ‘boundaries’ of communities (associations of species) and ecosystems are not very rigidly defined — thus demarcation is difficult and complex.

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3. Importance of Biodiversity

Biodiversity has contributed in many ways to the development of human culture and in turn, human communities have played a major role in shaping the diversity of nature at the genetic, species and ecological levels. Biodiversity plays three roles: Ecological, Economic and Scientific.

🌱 Ecological Role

Species of many kinds perform some function in an ecosystem. Every organism, besides extracting its needs, also contributes something useful to other organisms. Species: capture and store energy, produce and decompose organic materials, cycle water and nutrients, fix atmospheric gases, help regulate the climate.

The more diverse an ecosystem, better are the chances for species to survive and consequently, more productive it is. The more variety of species → more stable the ecosystem. Loss of species decreases the ability of the system to maintain itself.

💰 Economic Role

Biodiversity is an important resource in day-to-day life for all humans. One important part is ‘crop diversity’ — also called agro-biodiversity. Biodiversity is seen as a reservoir of resources for the manufacture of food, pharmaceutical and cosmetic products.

Important economic commodities biodiversity supplies to humankind: food crops, livestock, forests, fish, medicinal resources, etc.

🔬 Scientific Role

Biodiversity is important because each species can give clues as to how life evolved and will continue to evolve. Biodiversity helps in understanding how life functions and the role of each species in sustaining ecosystems of which we are also a species.

It is our ethical responsibility to recognise that each and every species has an intrinsic right to exist. Hence, it is morally wrong to voluntarily cause the extinction of any species.

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4. Loss of Biodiversity

Since the last few decades, growth in human population has increased the rate of consumption of natural resources. It has accelerated the loss of species and habitation in different parts of the world. Tropical regions occupy only about one-fourth of the total area of the world but contain about three-fourth of the world human population.

❌ Causes of Loss of Biodiversity

Over-exploitation of resources and deforestation: Rampant to fulfil the needs of large population. Tropical rain forests contain 50% of the species on Earth — their destruction has proved disastrous for the entire biosphere.
Natural calamities: Earthquakes, floods, volcanic eruptions, forest fires, droughts — cause damage to flora and fauna and bring changes in biodiversity of affected regions.
Pesticides and pollutants: Hydrocarbons and toxic heavy metals destroy the weak and sensitive species.
Exotic species: Species which are not natural inhabitants of the local habitat but are introduced into the system. Many examples where natural biotic community suffered extensive damage due to introduction of exotic species.
Poaching and illegal hunting: During the last few decades, animals like tigers, elephants, rhinoceros, crocodiles, minks and birds were hunted mercilessly by poachers for their horn, tusks, hides, etc. → rendering of certain organisms into endangered category.

📋 IUCN Categories of Threatened Species

📌 IUCN — International Union of Conservation of Nature and Natural Resources

The IUCN has classified the threatened species of plants and animals into three categories for the purpose of their conservation. The IUCN publishes information about endangered species world-wide as the Red List of threatened species.

🔴 Endangered Species

Species which are in danger of extinction. Their survival is unlikely if the factors causing their decline continue. Example: Red Panda. Published in IUCN’s Red List.

🟠 Vulnerable Species

Species which are likely to be in danger of extinction in the near future if the factors threatening to their extinction continue. Survival is not assured as their population has reduced greatly.

🟡 Rare Species

Population of these species is very small in the world. They are confined to limited areas or thinly scattered over a wider area. Not yet endangered or vulnerable but are at risk.

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5. Conservation of Biodiversity

Biodiversity is important for human existence. All forms of life are so closely interlinked that disturbance in one gives rise to imbalance in the others. If species of plants and animals become endangered, they cause degradation in the environment, which may threaten human being’s own existence.

🌍 Earth Summit — Convention on Biodiversity

📌 Earth Summit, 1992

The Government of India along with 155 other nations signed the Convention of Biodiversity at the Earth Summit held at Rio de Janeiro, Brazil in June 1992.

📋 World Conservation Strategy — Steps for Biodiversity Conservation

Efforts should be made to preserve the species that are endangered.
Prevention of extinction requires proper planning and management.
Varieties of food crops, forage plants, timber trees, livestock, animals and their wild relatives should be preserved.
Each country should identify habitats of wild relatives and ensure their protection.
Habitats where species feed, breed, rest and nurse their young should be safeguarded and protected.
International trade in wild plants and animals should be regulated.

🇮🇳 Wild Life (Protection) Act, 1972 — India

📌 India’s Conservation Law

To protect, preserve and propagate the variety of species within natural boundaries, the Government of India passed the Wild Life (Protection) Act, 1972, under which national parks and sanctuaries were established and biosphere reserves declared.

🌏 Mega Diversity Centres

📌 12 Mega Diversity Countries

Some countries situated in the tropical region possess a large number of the world’s species diversity. They are called mega diversity centres. There are 12 such countries:

Mexico, Colombia, Ecuador, Peru, Brazil, Democratic Republic of Congo, Madagascar, China, India, Malaysia, Indonesia and Australia.

🔥 Biodiversity Hotspots

🔥 What are Hotspots?

The IUCN has identified certain areas as biodiversity hotspots — to concentrate resources on those areas that are most vulnerable. Hotspots are defined according to their vegetation. Plants are important because they determine the primary productivity of an ecosystem.

🌺 Madagascar Example

In Madagascar, about 85% of the plants and animals are found nowhere else in the world — making it one of the most important biodiversity hotspots. The islands of Hawaii have many unique plants and animals threatened by introduced species and land development.

📌 Key Message

There is an urgent need to educate people to adopt environment-friendly practices and ensure that our development is harmonious with other life forms and is sustainable. Conservation with sustainable use is possible only with the involvement and cooperation of local communities and individuals. The critical problem is not merely the conservation of species nor the habitat but the continuation of the process of conservation.

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Summary — Quick Revision

Biodiversity: Bio (life) + Diversity (variety). Number and variety of organisms in a geographic region. Includes varieties of plants, animals, micro-organisms, their genes and ecosystems. Result of 2.5–3.5 billion years of evolution. Our “living wealth”.

Key Facts: Species estimate: 10 million (range 2–100 million). 99% of species that ever lived are now extinct. Average half-life of a species: 1–4 million years. Biodiversity richer in tropics; decreases towards poles. Tropical forests contain 50% of Earth’s species.

3 Levels: Genetic diversity (variation of genes within species — essential for healthy breeding), Species diversity (variety of species in an area — measured by richness, abundance, types), Ecosystem diversity (variety of habitats and ecological processes).

Importance — 3 Roles: Ecological (species capture energy, cycle nutrients, regulate climate — more diverse = more stable), Economic (food crops, livestock, forests, fish, medicines — agro-biodiversity), Scientific (clues to evolution, ethical responsibility — intrinsic right to exist).

Loss of Biodiversity — Causes: Over-exploitation and deforestation, Natural calamities, Pesticides and pollutants, Exotic species (not natural to local habitat), Poaching (tigers, elephants, rhinoceros, crocodiles for horn, tusks, hides).

IUCN 3 Categories: Endangered (in danger of extinction — Red List), Vulnerable (likely endangered in near future — population reduced greatly), Rare (very small population — confined to limited areas).

Conservation: Earth Summit — Rio de Janeiro, Brazil, June 1992 — India + 155 nations signed Convention of Biodiversity. Wild Life (Protection) Act, 1972 — national parks, sanctuaries, biosphere reserves established in India.

Mega Diversity Centres: 12 countries in tropical regions — Mexico, Colombia, Ecuador, Peru, Brazil, DR Congo, Madagascar, China, India, Malaysia, Indonesia, Australia. Hotspots: Defined by IUCN based on vegetation — most vulnerable areas. Madagascar: 85% species found nowhere else.

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Important Terms to Remember

Biodiversity: The number and variety of organisms (plants, animals, micro-organisms) found within a specified geographic region — including variability within and between species and ecosystems. Result of 2.5–3.5 billion years of evolution.
Genetic Diversity: Variation of genes within species. Enables differences in height, colour, physical appearance within the same species. Essential for healthy breeding of population of species.
Species: Groups of individual organisms having certain similarities in their physical characteristics. Homo sapiens is the species to which human beings belong.
Species Diversity: Refers to the variety and number of species in a defined area. Measured through richness, abundance and types.
Ecosystem Diversity: The broad differences between ecosystem types and the diversity of habitats and ecological processes occurring within each ecosystem type.
Hotspots of Diversity: Areas exceptionally rich in species diversity — identified by IUCN to concentrate conservation resources on the most vulnerable areas. Defined according to their vegetation (plants determine primary productivity).
Agro-biodiversity: Crop diversity — an important part of biodiversity directly related to human food security and agriculture.
Ecological Role of Biodiversity: Species capture and store energy, produce and decompose organic materials, cycle water and nutrients, fix atmospheric gases and help regulate the climate. More diverse ecosystem = more stable and productive.
Exotic Species: Species which are not natural inhabitants of the local habitat but are introduced into the system. Often cause extensive damage to natural biotic communities of the ecosystem.
IUCN: International Union of Conservation of Nature and Natural Resources. Classifies threatened species into three categories and publishes the Red List.
Red List: Published by IUCN — contains information about endangered species world-wide.
Endangered Species: Species in danger of extinction. Their survival is unlikely if the factors causing their decline continue. (Example: Red Panda)
Vulnerable Species: Species likely to be in danger of extinction in the near future if threatening factors continue. Survival is not assured — population has reduced greatly.
Rare Species: Species with very small populations in the world. Confined to limited areas or thinly scattered over a wider area.
Earth Summit (1992): Convention of Biodiversity signed at Rio de Janeiro, Brazil, June 1992. India and 155 other nations were signatories.
Wild Life (Protection) Act, 1972: Passed by Government of India to protect, preserve and propagate the variety of species. National parks, sanctuaries were established and biosphere reserves declared under this Act.

Mega Diversity Centres: Countries situated in the tropical region possessing a large number of the world’s species diversity. There are 12 such countries — Mexico, Colombia, Ecuador, Peru, Brazil, DR Congo, Madagascar, China, India, Malaysia, Indonesia and Australia.

Sustainable Development: Development that is harmonious with other life forms and meets present needs without compromising the ability of future generations to meet their own needs.