Biodiversity and Conservation

Biodiversity and Conservation closes the ecology unit and is one of the most fact-dense, high-scoring chapters in the syllabus — a dependable NEET presence and a favourite for CBSE 2- and 3-mark questions on the Evil Quartet, biodiversity hotspots, or in-situ versus ex-situ conservation. It moves from the three levels of biodiversity (genetic, species and ecological) through how many species there are on Earth and in India, the patterns of biodiversity (the latitudinal gradient and the species-area relationship with log S = log C + Z log A), the importance of species diversity to ecosystem stability (Tilman's experiments and Ehrlich's rivet-popper hypothesis), the loss of biodiversity and its four causes (the Evil Quartet), and finally why and how we conserve biodiversity (in-situ hotspots, biosphere reserves, national parks and sacred groves; ex-situ zoos, cryopreservation and seed banks, plus the Rio and Johannesburg summits). The chapter rewards precise recall of the numbers and named examples — India as one of 12 mega-diversity countries, the 34 hotspots with three in India, the IUCN Red List figures — set against a clear grasp of the mechanisms. Master the Evil Quartet, the species-area equation and the in-situ/ex-situ distinction and the marks follow.