Biodiversity and Conservation

The One Thing

Biodiversity is the variety of life at genetic, species, and ecosystem levels, and it is essential for ecosystem stability and human well-being. Conservation therefore aims to prevent biodiversity loss by protecting habitats, species, genetic variation, ecological processes, and ecosystem services.

Reactions, Processes and Experiments

Key Terms

• Biodiversity: The variety and variability of living organisms and the ecological complexes in which they occur.
• Genetic diversity: Variation in genes within a species, such as the different varieties of rice, wheat, or mango.
• Species diversity: The variety of species in a region and their relative abundance.
• Ecosystem diversity: The variety of ecosystems, habitats, and ecological processes in an area.
• Species richness: The number of species present in a particular area.
• Species-area relationship: A relationship showing that larger areas generally contain more species; it is represented by S = C A^Z, or log S = log C + Z log A.
• Latitudinal gradient: The general pattern in which species richness decreases from the equator toward the poles.
• Endemic species: A species naturally restricted to a particular geographical region.
• Biodiversity hotspot: A region with exceptionally high endemism that has undergone severe habitat loss.
• Extinction: The permanent disappearance of a species from Earth.
• The evil quartet: The four major causes of biodiversity loss: habitat loss and fragmentation, overexploitation, alien species invasion, and co-extinctions.
• Habitat fragmentation: The breaking of a large continuous habitat into smaller, isolated patches.
• Overexploitation: Excessive use or harvesting of organisms faster than their populations can recover.
• Alien species invasion: The introduction of non-native species that may outcompete, prey on, or replace native organisms.
• Co-extinction: The extinction of one species following the disappearance of another species with which it is closely associated.
• In situ conservation: Conservation of organisms within their natural habitats, such as national parks, wildlife sanctuaries, and biosphere reserves.
• Ex situ conservation: Conservation outside natural habitats, such as zoos, botanical gardens, seed banks, gene banks, and cryopreservation facilities.
• Biosphere reserve: A large protected area designed to conserve biodiversity while allowing compatible research, education, and sustainable human activities.
• National park: A protected area managed primarily for the conservation of ecosystems, wildlife, and natural features, with highly restricted human activities.
• Wildlife sanctuary: A protected area established mainly for wildlife conservation, where some regulated human activities may be permitted.
• Red Data Book: A record of threatened species and information about their conservation status.
• Sacred groves: Forest patches protected by local communities because of cultural or religious beliefs, often preserving rare species.
• Ecosystem services: Benefits provided by ecosystems, including pollination, climate regulation, soil formation, water purification, and nutrient cycling.

Easily Confused

• Genetic diversity vs species diversity: Genetic diversity is variation within a species, whereas species diversity concerns the variety and relative abundance of species in a region.
• Species diversity vs species richness: Species richness is only the number of species present, whereas species diversity also considers their relative abundance.
• Species richness vs biodiversity: Species richness measures the number of species in an area; biodiversity includes genetic, species, and ecosystem diversity.
• In situ vs ex situ conservation: In situ conservation protects organisms in their natural habitats, whereas ex situ conservation maintains organisms or genetic material outside those habitats.
• National parks vs wildlife sanctuaries: National parks impose highly restricted human activities, whereas wildlife sanctuaries may permit some regulated human activities.
• Biosphere reserves vs national parks: Biosphere reserves are large areas that may permit compatible research, education, and sustainable human activities, while national parks focus on conservation with highly restricted human use.
• Habitat loss vs habitat fragmentation: Habitat loss reduces the total amount of habitat, whereas fragmentation divides remaining habitat into smaller isolated patches.
• Alien species invasion vs co-extinction: Alien species invasion involves the harmful introduction of a non-native species, whereas co-extinction occurs when one species disappears following the loss of an associated species.
• Endemic species vs biodiversity hotspot: An endemic species is restricted to one geographical region; a biodiversity hotspot is a region with high endemism and severe habitat loss.
• Seed banks and gene banks vs cryopreservation: Seed banks and gene banks store genetic material for future use, whereas cryopreservation stores cells, tissues, embryos, or gametes at extremely low temperatures, commonly in liquid nitrogen.

What Gets Asked

• Questions may require the three levels of biodiversity to be identified: genetic diversity, species diversity, and ecosystem diversity. A common error is treating species richness as equivalent to all biodiversity.
• The species-area relationship may be tested using S = C A^Z or log S = log C + Z log A. Marks may be lost by omitting the meanings of S, A, C, or Z, or by confusing Z with the constant C.
• Questions may ask why tropical regions generally have greater species richness. The relevant factors are stable climate, greater solar energy, and longer evolutionary history.
• The four causes known as the evil quartet may be required: habitat loss and fragmentation, overexploitation, alien species invasion, and co-extinctions. Omitting habitat destruction and fragmentation is especially significant because it is identified as the most important cause of biodiversity decline.
• Conservation questions may require a comparison of in situ and ex situ methods, including national parks, wildlife sanctuaries, biosphere reserves, sacred groves, zoological parks, botanical gardens, aquaria, seed banks, tissue culture, and cryopreservation.
• Questions may test Indian biodiversity and international conservation. The required details include India’s four biodiversity hotspots—the Himalaya, Indo-Burma, Western Ghats-Sri Lanka, and Sundaland, with the Indian region of Sundaland represented mainly by the Nicobar Islands—and the adoption of the Convention on Biological Diversity at the Earth Summit in Rio de Janeiro in 1992.