Biodiversity refers to the totality of genes, species, and ecosystems of a region. The term was popularized by sociobiologist Edward Wilson and encompasses the variety and variability of life forms at all levels of biological organization.
Biodiversity can be described at three levels: genetic diversity (variation in genes within a species), species diversity (variety of species in a region), and ecological diversity (variety of ecosystems in a region). India is one of the 12 mega-biodiversity countries in the world, with about 45,000 plant species and 91,000 animal species.
Species diversity is measured using diversity indices. The most commonly used is the Shannon-Wiener Index (H'), where a higher value indicates greater diversity. Species-area relationship, described by Alexander von Humboldt, follows the equation log S = log C + Z log A, where S is species richness, A is area, Z is the slope (regression coefficient, typically 0.1–0.2 for smaller areas and 0.6–1.2 for very large areas like continents), and C is the y-intercept.
The current rate of species extinction is 100 to 1,000 times faster than the natural background rate, primarily due to human activities. The major causes of biodiversity loss can be remembered by the acronym HIPPO: Habitat loss and fragmentation, Invasive species, Pollution, Population growth (overexploitation), and Over-harvesting.
Biodiversity hotspots are regions with exceptionally high species richness and high degree of endemism that are under threat. Norman Myers defined 34 biodiversity hotspots worldwide. India has four hotspots: Western Ghats, Himalayas, Indo-Burma, and Sundaland.
Conservation strategies are of two types: in-situ conservation (protecting species in their natural habitat — national parks, wildlife sanctuaries, biosphere reserves) and ex-situ conservation (protecting species outside their natural habitat — zoos, botanical gardens, seed banks, cryopreservation).
Solve previous year NEET questions from this chapter with answers.
Practice PYQs →Browse all subtopics and key concepts from this chapter.
View Subtopics →Browse all 32 chapters of NEET Biology previous year questions.
Browse All →12,771+ questions covering all Biology chapters — master Biodiversity and every other NEET topic with chapter-wise practice.