Biodiversity and Conservation

Notes

Chapter Overview

Biodiversity refers to the variety and variability of living organisms on Earth. It includes diversity at the genetic, species, and ecosystem levels. Biodiversity is essential for ecological balance, human survival, and sustainable development.

Conservation means the protection, preservation, and sustainable use of biodiversity to ensure that it remains available for future generations.

1. Biodiversity

Definition

Biodiversity is the variety of life forms found on Earth, including plants, animals, microorganisms, and the ecosystems in which they live.

Importance

Maintains ecological balance.

Provides food, medicine, fuel, and raw materials.

Supports ecosystem services.

Ensures environmental stability.

2. Levels of Biodiversity

(A) Genetic Diversity

Variation of genes within a species.

Examples

Different varieties of rice in India.

Different breeds of cattle.

Mango varieties.

Importance

Helps species adapt to environmental changes.

Increases disease resistance.

(B) Species Diversity

Variety of different species present in an area.

Example

Western Ghats have thousands of plant and animal species.

(C) Ecological Diversity

Variety of ecosystems within a geographical region.

Examples

Forest

Desert

Grassland

Wetland

Mangrove

Mountain ecosystem

3. India as a Mega-diversity Nation

India is one of the 17 mega-diverse countries of the world.

Facts

Covers only 2.4% of Earth's land area.

Supports about 8.1% of the world's recorded species.

Contains four biodiversity hotspots.

4. Biodiversity Hotspots

A biodiversity hotspot is a region with a high level of endemic species that is under serious threat from habitat loss.

Criteria (Norman Myers)

At least 1,500 endemic vascular plant species.

More than 70% habitat loss.

Biodiversity Hotspots in India

Himalaya

Indo-Burma

Western Ghats & Sri Lanka

Sundaland (Nicobar Islands)

5. Patterns of Biodiversity

(A) Latitudinal Gradient

Species diversity:

Highest in the tropics.

Decreases towards the poles.

Reason

Stable climate

Longer evolutionary time

High productivity

Example:

Amazon Rainforest.

(B) Species-Area Relationship

Larger area supports more species.

Formula

S = CAᶻ

Where:

S = Number of species

A = Area

C = Constant

Z = Regression coefficient

Log Form

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