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| Levels of Biodiversity |
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| Biological diversity includes 3 hierarchical levels. |
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| a) Genetic diversity |
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| b) Species diversity |
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| c) Community and ecosystem diversity |
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| It refers to the variation of genes within a species. The genetic diversity enables a population to adapt to its environment and to respond to natural selection. The amount of genetic variation is the basis of speciation. Genetic diversity within a species often increases with environmental variability. |
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| Species are distinct units of diversity each playing a specific role in the ecosystem. Species diversity refers to the variety of species within a region. In nature, both the number and kind of species, as well as the number of individuals per species vary, leading to greater diversity. |
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| The different sample areas showing species richness (sample area 1), Species evenness (sample area 2) and diversity due to taxonomically unrelated species (sample area 3) |
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| Diversity at the level of community and ecosystem exists along 3 levels. It could be within-community diversity (alpha diversity), between-communities diversity (beta diversity) or diversity of the habitats over the total landscape or geographical area (gamma diversity). |
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| Three perspectives of diversity: alpha, beta and gamma diversity |
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| Biogeographical regions of India |
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