Class 12 Biology - KARNATAKA
Biodiversity and Conservation
The chapter Biodiversity and Conservation in Class 12 Biology explores the immense variety of life on Earth at genetic, species, and ecological levels, and why this rich diversity is vital for ecosystem health and human survival. Students will study patterns of biodiversity across the globe, the alarming rates of current extinction driven by human activities, and the ethical, economic, and ecological reasons for preserving biodiversity. Additionally, the chapter covers crucial conservation strategies, including in-situ methods like national parks and hotspots, and ex-situ methods like botanical gardens and seed banks, which are frequently tested in Karnataka (KSEEB) board exams.
Start Learning FreeKey Concepts
Levels of Biodiversity
Biodiversity exists at three hierarchical levels: genetic diversity (variation within species), species diversity (variety of species within a region), and ecological diversity (variety of ecosystems within a geographical location).
Latitudinal Gradients in Biodiversity
Species diversity generally decreases as we move away from the equator towards the poles, making tropical regions hotspots of high species richness compared to temperate zones.
The Evil Quartet
The four major causes of accelerated biodiversity loss are Habitat loss and fragmentation, Over-exploitation, Alien species invasions, and Co-extinctions.
In-situ Conservation
The conservation of endangered plants and animals in their natural habitats, such as national parks, wildlife sanctuaries, biosphere reserves, and biodiversity hotspots.
Ex-situ Conservation
The conservation of threatened species outside their natural habitats through methods like botanical gardens, zoological parks, cryopreservation, and seed banks.
Important Formulas
Board Exam Info
In the Karnataka (KSEEB) Class 12 Biology board exams, this chapter typically carries around 4 to 6 marks. Questions commonly include 1-mark objective questions, 2-mark definitions (e.g., hotspots, endemic species), and 3 to 5-mark descriptive questions explaining the 'Evil Quartet' or the difference between in-situ and ex-situ conservation.
Frequently Asked Questions
What is the significance of the Species-Area relationship equation?
The equation log S = log C + Z log A shows that within a region, species richness increases with increasing explored area, but only up to a certain limit. The slope of the line (Z) represents the regression coefficient, which is steeper for larger areas like continents.
What is the difference between In-situ and Ex-situ conservation?
In-situ conservation protects species within their natural habitat (e.g., National Parks), whereas ex-situ conservation protects endangered species outside their natural habitat in man-made facilities (e.g., Zoos and Botanical gardens).
Why are tropical regions rich in biodiversity?
Tropical regions receive more solar energy, have remained undisturbed for millions of years allowing more time for species diversification, and experience less seasonal variation, providing a stable environment for a wide variety of species.
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