Biodiversity

• The diversity of life forms present on Earth, including plants, animals, and microorganisms, is called biodiversity.
• Biodiversity is the occurrence of different types of genes among the individuals of species, habitats and ecosystems, both terrestrial and aquatic, within a defined area.

• Biodiversity means the variety and variability of living organisms on Earth, including plants, animals, fungi, and microorganisms found in terrestrial and aquatic habitats.
• It includes variation at three levels: genetic diversity, species diversity, and ecosystem diversity.
• Biodiversity is the totality of genes, species, and ecosystems present in a region.

Main idea:

• Diversity in living organisms can be seen in size, shape, colour, nutrition, habitat, and reproduction.
• This diversity develops due to adaptations to different environmental conditions.
• Present biodiversity is the result of about 3.5 billion years of evolution.
• The term biodiversity was coined by Walter Rosen and later popularised by Edward Wilson.

1. Genetic diversity

• Genetic diversity means variation in genes within the same species.
• It helps species survive changing environmental conditions and supports adaptation.
• Example: genetic variation in Rauwolfia vomitoria or different crop varieties.

2. Species diversity

• Species diversity means the variety of species present in a particular region or ecological community.
• A region with more species has higher species diversity.
• Example: Western Ghats have more amphibian species than Eastern Ghats.

3. Ecosystem diversity

• Ecosystem diversity means the variety of ecosystems in a region.
• It includes habitats such as deserts, mangroves, rainforests, wetlands, grasslands, and mountains.
• Greater ecosystem diversity supports more ecological interactions and life forms.

• Biodiversity helps maintain ecological balance and ecosystem stability.
• Ecosystems with high biodiversity are generally more productive, more stable, and more resistant to disturbances such as floods and alien species invasion.
• Biodiversity provides useful resources such as food, medicine, fuel, and fibres.
• It also supports ecosystem services such as pollination, nutrient cycling, soil protection, and climate regulation.
• Each species plays an important role in the ecosystem, so the loss of one species can disturb food chains and ecological balance.

• Living organisms are found from mountain peaks to ocean depths, and from deserts to rainforests.
• The number of species per unit area declines from tropical regions towards the poles.
• Northern cold regions have fewer tree species, while tropical forests have much greater species richness in a small area.

• Biodiversity is the variety of life on Earth - including microorganisms, fungi, plants and animals in both terrestrial and aquatic habitats.
• Diversity exists in size, shape, colour, nutrition, habitat and reproduction. It arises due to adaptations of organisms to different environmental conditions for survival.
• Biodiversity = totality of genes, species and ecosystems in a region (as per IUCN, UNEP and WRI).
• Term coined by Walter Rosen (1982), popularised by Edward Wilson to describe diversity at all levels of biological organisation.
• Today's biodiversity is the result of 3.5 billion years of evolutionary history, influenced by natural processes and human activities.