Class 12 Biology - ISC
Biodiversity and Conservation
The chapter Biodiversity and Conservation in ISC Class 12 Biology explores the immense variety of life on Earth at genetic, species, and ecological levels. Students learn about patterns of biodiversity, gradients, and the alarming rate of species loss driven by human activities, famously acronymized as 'The Evil Quartet'. The chapter emphasizes why biodiversity is crucial for ecosystem stability and human survival, detailing various in-situ and ex-situ conservation strategies like national parks, hotspots, and seed banks. For board exams, this is a high-scoring, concept-driven chapter that frequently tests students on ecological principles, conservation legislation, and data interpretation from graphical representations.
Start Learning FreeKey Concepts
Levels of Biodiversity
Biodiversity exists at three hierarchical levels: genetic diversity (variety of genes within a species), species diversity (variety of species within a region), and ecological diversity (variety of ecosystems in a biome).
Latitudinal Gradients of Biodiversity
Species diversity decreases as we move away from the equator towards the poles, making tropical regions rich hotspots of biodiversity due to favorable, stable climates and uninterrupted evolutionary time.
Species-Area Relationship
Alexander von Humboldt observed that within a region, species richness increases with increasing explored area, but only up to a limit, represented mathematically by a rectangular hyperbola.
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 vs. Ex-situ Conservation
In-situ conservation protects endangered species in their natural habitats (e.g., national parks, biosphere reserves), whereas ex-situ conservation protects them outside their natural habitats (e.g., zoological parks, botanical gardens, cryopreservation).
Important Formulas
Board Exam Info
In the ISC Class 12 Biology examination, this chapter is part of the Ecology unit, which typically carries around 10 to 14 marks in total. Questions frequently include short-answer questions on 'The Evil Quartet', reasons for high tropical biodiversity, differences between in-situ and ex-situ conservation, and numerical or conceptual problems based on the Species-Area relationship equation.
Frequently Asked Questions
What do the variables 'Z' and 'C' represent in the species-area relationship equation?
'Z' is the regression coefficient (slope of the line, usually between 0.1 and 0.2, but 0.6 to 1.2 for large continents), and 'C' is the Y-intercept representing the species richness.
What is the difference between a National Park and a Biosphere Reserve?
A National Park is strictly reserved for the betterment of wildlife where human activity like grazing is prohibited, whereas a Biosphere Reserve is a large area meant for conserving biodiversity and traditional life of humans through multiple zones (core, buffer, transition).
Why are alien species invasions harmful to native biodiversity?
Alien species introduced unintentionally or deliberately can become invasive, reproduce rapidly in the absence of natural predators, and outcompete native species for resources, often leading to native species extinction.
Learn Biodiversity and Conservation with Your AI Tutor
10 different ways to study this chapter. Free for 3 chapters per day.
Lecture
Key Points
Interactive
Quiz
Flashcards