Biodiversity and Conservation Class 11 Geography Notes

This chapter explains the meaning, levels and importance of biodiversity along with major threats and conservation measures. It highlights the ecological, economic and scientific significance of biodiversity and explains why biodiversity conservation is essential for sustainable development.

• Meaning of biodiversity
• Levels of biodiversity
• Genetic diversity
• Species diversity
• Ecosystem diversity
• Importance of biodiversity
• Ecological role
• Economic role
• Scientific role
• Loss of biodiversity
• Threatened species
• Conservation of biodiversity
• Biodiversity hotspots
• Wildlife Protection Act, 1972

Meaning of Biodiversity

Biodiversity means the variety of life forms present on Earth. It includes plants, animals and microorganisms along with their genes and ecosystems.

• Variety of life forms
• Variety of plants, animals and microorganisms
• Includes genes, species and ecosystems

Evolution of Biodiversity

Biodiversity evolved over billions of years. Human activities have accelerated the extinction of many species.

• Developed over 2.5–3.5 billion years
• Earth earlier supported greater biodiversity
• Human activities increased extinction rates

Distribution of Biodiversity

Biodiversity is not equally distributed across the world.

• Richest in tropical regions
• Decreases towards polar regions

Biodiversity is generally studied at three major levels.

1. Genetic Diversity
2. Species Diversity
3. Ecosystem Diversity

Meaning of Genetic Diversity

Genetic diversity refers to variation of genes within a species.

• Genes are building blocks of life
• Variation occurs within species

Example

• Human beings belong to Homo sapiens
• Differences exist in colour, height and appearance

Importance

• Healthy breeding
• Adaptation to environment
• Survival of species

Meaning of Species Diversity

Species diversity refers to the variety of species found in a particular area.

• Depends on richness of species
• Depends on abundance of species
• Includes different types of species

Biodiversity Hotspots

Areas rich in species diversity are known as biodiversity hotspots.

Meaning of Ecosystem Diversity

Ecosystem diversity refers to the variety of ecosystems, habitats and ecological processes.

Example

• Grasslands and sholas of Western Ghats

Ecosystem Boundaries

• Boundaries are not rigid
• Difficult to define clearly

Biodiversity plays ecological, economic and scientific roles in maintaining life on Earth.

Ecological Role

• Energy storage
• Nutrient cycling
• Water cycling
• Climate regulation
• Organic matter decomposition
• Maintains ecosystem stability

Economic Role

• Food crops
• Livestock
• Forest resources
• Medicinal resources
• Supports pharmaceutical and cosmetic industries

Scientific Role

• Helps understand evolution
• Study ecosystem functioning
• Supports scientific research

Major Causes

1. Population growth
2. Over-exploitation of resources
3. Deforestation
4. Pollution
5. Exotic species
6. Poaching
7. Natural disasters

Deforestation

• Tropical forests contain nearly 50% of world species
• Causes habitat destruction
• Leads to species extinction

Pollution

• Pesticides
• Hydrocarbons
• Toxic heavy metals

Poaching

• Illegal hunting of animals
• Tigers, elephants and rhinoceros affected

IUCN Classification

The International Union for Conservation of Nature (IUCN) classifies threatened species into categories.

1. Endangered species
2. Vulnerable species
3. Rare species

Endangered Species

• Species in danger of extinction
• IUCN publishes Red List
• Example: Red Panda

Vulnerable Species

• Likely to become endangered soon
• Population reduced greatly

Rare Species

• Very small population
• Exist in limited areas

Need for Conservation

• Life forms are interlinked
• Extinction causes ecological imbalance
• Human survival depends on biodiversity

World Conservation Strategy

1. Protect endangered species
2. Prevent extinction
3. Preserve food crops and wild relatives
4. Protect habitats
5. Regulate wildlife trade

Wildlife Protection Act, 1972

• Protects wildlife in India
• Establishes national parks
• Creates sanctuaries and biosphere reserves

Meaning of Hotspots

Hotspots are regions with rich biodiversity that are under threat.

Importance

• Need urgent conservation
• Contain unique species

Examples

• Western Ghats
• Eastern Himalayas
• Madagascar
• Tropical Andes
• Philippines

Very Short Answer Questions

1. What is biodiversity?
2. What is genetic diversity?
3. What are biodiversity hotspots?
4. What are exotic species?
5. What is agro-biodiversity?

Short Answer Questions

1. Explain the meaning of species diversity.
2. Discuss ecological role of biodiversity.
3. Explain causes of biodiversity loss.
4. What are endangered species?
5. Explain the importance of biodiversity hotspots.

Long Answer Questions

1. Explain the different levels of biodiversity.
2. Discuss the importance of biodiversity for human survival.
3. Explain the causes and impacts of biodiversity loss.
4. Discuss conservation measures for biodiversity.
5. Explain the role of biodiversity in maintaining ecological balance.

1. What is biodiversity?

Biodiversity means variety of plants, animals and microorganisms.

2. Which regions are richest in biodiversity?

Tropical regions are richest in biodiversity.

3. What are biodiversity hotspots?

Areas with rich species diversity under threat are called hotspots.

4. What is the role of IUCN?

IUCN classifies threatened species and promotes conservation.

5. What is the Wildlife Protection Act, 1972?

An Indian law for wildlife conservation and protection.

• Biodiversity:
  • Variety of life forms
• Levels:
  • Genetic diversity
  • Species diversity
  • Ecosystem diversity
• Biodiversity richest in:
  • Tropical regions
• Importance:
  • Ecological
  • Economic
  • Scientific
• Ecological Functions:
  • Nutrient cycling
  • Climate regulation
  • Ecosystem stability
• Economic Uses:
  • Food
  • Medicine
  • Forest products
• Causes of Biodiversity Loss:
  • Deforestation
  • Pollution
  • Population growth
  • Poaching
  • Exotic species
• Threatened Species:
  • Endangered
  • Vulnerable
  • Rare
• Conservation:
  • National parks
  • Sanctuaries
  • Biosphere reserves
• Wildlife Protection Act:
  • 1972
• Earth Summit:
  • Rio de Janeiro
  • 1992
• Hotspots:
  • Regions of high biodiversity
• Mega Diversity Countries:
  • India
  • Brazil
  • China
  • Indonesia