Unit3 - Subjective Questions

Definition: Biodiversity (Biological Diversity) refers to the variety and variability of life on Earth. It encompasses the variability among living organisms from all sources including terrestrial, marine, and other aquatic ecosystems and the ecological complexes of which they are part.

Levels of Biodiversity:

1. Genetic Diversity: This refers to the variation of genes within a species. It covers distinct populations of the same species or genetic variation within a population (e.g., different varieties of rice or breeds of dogs).
2. Species Diversity: This refers to the variety of species within a region. It is often measured by species richness (number of species) and species evenness (relative abundance of each species).
3. Ecosystem Diversity: This refers to the diversity of habitats, biological communities, and ecological processes in the biosphere. It includes the variety of ecosystems like forests, deserts, coral reefs, and wetlands.

India is recognized as one of the 17 mega-diversity nations in the world. The justification includes:

• Geographical Position: Situated at the confluence of three biogeographic realms (Afrotropical, Indomalayan, and Paleoarctic), allowing for diverse species.
• Species Richness: India possesses about 7-8\% of the world's recorded species, despite having only 2.4\% of the world's land area.
• Endemism: A significant percentage of Indian plants (approx. 33\%) and animals are endemic (found nowhere else), particularly in the Western Ghats and Himalayas.
• Center of Origin: India is a center of origin for many cultivated plants like rice, sugarcane, and mangoes.
• Marine Diversity: With a coastline of over 7,500 km, India has rich marine biodiversity, including mangroves and coral reefs.

Biodiversity underpins ecosystem functions that provide goods and services vital to human survival:

1. Provisioning Services: Products obtained from ecosystems, such as food (crops, fish), fresh water, wood, fiber, genetic resources, and medicines.
2. Regulating Services: Benefits obtained from the regulation of ecosystem processes, including:
   • Climate regulation (carbon sequestration by forests).
   • Flood control (wetlands absorbing excess water).
   • Disease regulation and water purification.
3. Supporting Services: Services necessary for the production of all other ecosystem services, such as soil formation, photosynthesis, and nutrient cycling.
4. Cultural Services: Non-material benefits people obtain through spiritual enrichment, cognitive development, recreation, and aesthetic experiences.

Definition: Biodiversity hotspots are regions with very high levels of species richness and a high degree of endemism that are also under significant threat from human activity.

Criteria (Norman Myers):

1. Endemism: The region must contain at least 1,500 species of vascular plants ( of the world's total) as endemics.
2. Threat: It must have lost at least 70\% of its primary vegetation.

Hotspots in India:

1. The Himalayas
2. The Western Ghats
3. Indo-Burma Region (North-East India)
4. Sundaland (Nicobar Islands)

Consumptive Use Value:

• Definition: Refers to natural products that are harvested and consumed directly by people without passing through a market.
• Context: Common in rural or indigenous communities.
• Examples: Firewood collected for cooking, wild fruits, animals hunted for food (bushmeat), and medicinal herbs used locally.

Productive Use Value:

• Definition: Refers to products that are commercially harvested and marketed (sold).
• Context: Contributes directly to the national economy.
• Examples: Timber/lumber industry, fish sold in markets, ivory (though illegal, it has economic value), medicinal plants sold to pharmaceutical companies, and gums/resins.

Habitat Loss:

• This is the primary cause of species extinction. It occurs when natural environments (forests, wetlands, grasslands) are converted for human uses such as agriculture, urbanization, and industrialization.
• Impact: Organisms lose their homes, food sources, and breeding grounds.

Habitat Fragmentation:

• Large, continuous habitats are divided into smaller, isolated patches (fragments) due to roads, canals, or fields.
• Consequences:
  1. Edge Effect: The outer boundary of the fragment is exposed to different microclimates, affecting species adapted to the deep forest.
  2. Isolation: Populations become isolated, reducing gene flow and increasing the risk of inbreeding.
  3. Limited Resources: Smaller fragments cannot support animals with large home ranges (e.g., tigers, elephants).

Concept: Human-Wildlife Conflict (HWC) refers to struggles that arise when the presence or behavior of wildlife poses actual or perceived, direct and recurring threats to human interests or needs, leading to disagreements between groups of people and negative impact on wildlife or humans.

Causes:

• Habitat Encroachment: Expansion of agriculture and settlements into forest areas.
• Resource Competition: Livestock grazing in forests reduces food for herbivores, driving predators to attack livestock.
• Fragmented Corridors: Disruption of migratory paths (e.g., for elephants).

Mitigation Strategies:

• Barriers: Solar fencing and trenches to prevent animal entry.
• Compensation: Prompt payment for crop or livestock loss to prevent retaliation killing.
• Corridors: Creating and maintaining wildlife corridors.
• Technology: Early warning systems (SMS alerts, sensors) to detect animal movement.

Biological Invasions:
The introduction of non-native (alien) species into a new ecosystem where they establish, spread, and cause harm to the native biodiversity, economy, or human health.

Impacts:

1. Competition: Invasive species often outcompete native species for resources (food, light, space) because they lack natural predators in the new environment.
2. Predation: They may prey on native species that have no defense mechanisms against them.
3. Altering Ecosystems: They can change soil chemistry or fire regimes.

Examples:

• Water Hyacinth (Eichhornia crassipes): Clogs water bodies, reduces oxygen levels, and kills fish.
• Lantana (Lantana camara): Takes over forest undergrowth, preventing the growth of native saplings.
• Parthenium (Carrot Grass): Causes allergies in humans and suppresses native vegetation.

These definitions are based on the IUCN Red List:

1. Extinct (EX): A taxon is Extinct when there is no reasonable doubt that the last individual has died. Extensive surveys in known and/or expected habitat have failed to record an individual (e.g., Dodo, Passenger Pigeon).

2. Endangered (EN): A taxon is Endangered when the best available evidence indicates that it faces a very high risk of extinction in the wild in the near future (e.g., Bengal Tiger, Blue Whale).

3. Vulnerable (VU): A taxon is Vulnerable when it faces a high risk of extinction in the wild in the medium-term future, though not as critically as endangered species (e.g., Indian Rhinoceros, Polar Bear).

Definition: EDGE stands for Evolutionarily Distinct and Globally Endangered. These are species that have few close genetic relatives (they are distinct on the 'Tree of Life') and are also critically endangered.

Importance:

• Unique Evolutionary History: Losing an EDGE species means losing a disproportionate amount of the earth's evolutionary history and unique genetic traits.
• Irreplaceability: Because they have few relatives, if they go extinct, there is nothing similar left on the planet.
• Examples: The Purple Frog (India), Pangolins, and the Ganges River Dolphin.

The Wildlife Institute of India classifies the country into ten biogeographic zones based on climate, soil, flora, and fauna:

1. Trans-Himalaya: Cold desert regions (Ladakh).
2. Himalaya: The entire mountain chain.
3. Desert: The arid regions of the west (Thar, Kutch).
4. Semi-Arid: The zone between the desert and the Deccan plateau.
5. Western Ghats: High rainfall, biodiversity hotspot.
6. Deccan Peninsula: The largest zone, covering the central plateau.
7. Gangetic Plain: The flat, alluvial fertile plains.
8. Coast: The coastline and mangroves.
9. North-East: The tropical transition zone to Indo-Malaya.
10. Islands: Andaman & Nicobar, and Lakshadweep.

Aesthetic Value:

• Biodiversity contributes to the beauty of the landscape. The presence of wildlife, flowers, and forests provides psychological well-being and visual pleasure.
• Ecotourism: This value translates into economic benefits through tourism (bird watching, wildlife safaris, nature photography).

Informational Value:

• Genetic Library: Each species carries genetic information evolved over millions of years. This data allows scientists to understand the processes of life.
• Biomimetics: Studying nature inspires engineering solutions (e.g., studying birds for flight dynamics, lotus leaves for waterproof materials).
• Scientific Research: Biodiversity serves as a reference for monitoring environmental changes and pollution.

Causes:

1. Illegal Trade: High demand for animal parts (tiger skin, ivory tusks, rhino horns) in international markets.
2. Traditional Medicine: Beliefs in the medicinal properties of animal parts (e.g., bear bile, tiger bones) in Traditional Chinese Medicine.
3. Food: Hunting for bushmeat.
4. Ornaments/Fashion: Use of fur, feathers, and leather.

Consequences:

1. Population Decline: Rapid reduction in species numbers leading to local or global extinction.
2. Ecosystem Imbalance: Removal of keystone species (like top predators) disrupts the food web, leading to overpopulation of prey (herbivores) and degradation of vegetation.
3. Loss of Genetic Diversity: Reduces the gene pool, making species less resilient.

Role:
Biosphere Reserves are special environments for both people and nature. They promote sustainable development based on local community efforts and sound science.

Zonation:

1. Core Zone: Strictly protected area where human activity is not allowed (except monitoring). It preserves the pristine ecosystem.
2. Buffer Zone: Surrounds the core. Limited non-destructive activities are allowed, such as research, education, and ecotourism.
3. Transition Zone: The outermost part where settlements, croplands, and managed forests exist. Here, local communities, management agencies, and scientists work together to use resources sustainably.

Definition: Cryopreservation is an advanced Ex-situ conservation technique where biological material (seeds, pollen, tissue, embryos, or DNA) is stored at extremely low temperatures, usually in liquid nitrogen at .

Significance:

• Long-term Storage: Metabolic activities stop, allowing material to be stored for decades or centuries without deterioration.
• Space Efficient: Large amounts of genetic diversity can be stored in a small space.
• Recalcitrant Seeds: Useful for species whose seeds cannot be dried and stored in standard seed banks.
• Insurance: Acts as a backup for species that are critically endangered in the wild.

Rare Species:

• Definition: Species with small total population sizes that are not currently endangered or vulnerable but are at risk.
• Distribution: They may be thinly scattered over a wide area.
• Example: The Himalayan Brown Bear is rare but found in several countries.

Endemic Species:

• Definition: Species that are confined to a specific geographical region and are found nowhere else in the world.
• Distribution: Highly restricted to one location (e.g., an island, a mountain range).
• Example: The Lion-tailed Macaque is endemic to the Western Ghats of India.

Note: An endemic species is often rare, but a rare species is not necessarily endemic.

Social Value:

• Biodiversity is integral to the cultural, religious, and social life of people.
• Many plants and animals are considered holy (e.g., Tulsi, Peepal, Cow in India).
• Tribal communities are directly dependent on forests for their lifestyle and social structure.

Ethical Value (Existence Value):

• Based on the principle that all forms of life have a right to exist, regardless of their utility to humans.
• Stewardship: Humans have a moral responsibility to protect other species and hand over a healthy planet to future generations.
• "We do not inherit the earth from our ancestors; we borrow it from our children."

Definition: Genetic diversity is the variety of alleles and genotypes present in a population.

Contribution to Adaptability:

1. Resistance to Disease: A genetically diverse population is less likely to be wiped out by a single pathogen. Some individuals may possess natural immunity genes.
2. Environmental Change: If the climate changes (e.g., higher temperatures), individuals with genetic variants suited for heat tolerance will survive and reproduce, ensuring the species continues.
3. Evolutionary Potential: Genetic variation is the raw material for natural selection. Without it, a species cannot evolve to meet new challenges, leading to inbreeding depression and extinction.

National Parks (NP):

• Highly protected areas designated by the government for the conservation of wildlife and natural environment.
• Strict Rules: No human activity is allowed (grazing, private ownership, forestry) unless specifically permitted for management.
• Example: Jim Corbett National Park, Kaziranga National Park.

Wildlife Sanctuaries (WLS):

• Protected areas oriented towards the conservation of specific species or general wildlife.
• Moderate Rules: Limited human activities like harvesting timber, collecting minor forest products, and private ownership rights may be allowed if they don't interfere with wildlife well-being.
• Example: Periyar Wildlife Sanctuary, Bharatpur Bird Sanctuary.

Key Difference: NPs have a higher degree of protection and stricter restrictions on human interference compared to WLS.