Ecology, Biodiversity and Conservation

Ecosystems

• Structure and function of ecosystems:
  • Components: biotic (producers, consumers, decomposers) and abiotic (physical and chemical factors).
  • Energy flow: pathways of energy transfer through trophic levels, food chains, food webs.
  • Nutrient cycling: biogeochemical cycles (carbon, nitrogen, phosphorus, etc.) and their significance.

(References: NCERT Biology Class 11, Chapter 14, Chapter 15)

Biodiversity

• Importance: ecological processes, ecosystem services, genetic resources, medicinal potential, aesthetic and cultural values.
• Types of biodiversity:
  • Genetic diversity: variations in genes within a population.
  • Species diversity: variety of species in a region.
  • Ecosystem diversity: different ecosystems and habitats.
• Measurement and indices: species richness, species diversity indices (Shannon-Wiener index, Simpson’s index), evenness.
• Species-area relationship: positive correlation between species richness and area.
• Ecological hotspots: areas with high species richness and endemism, conservation significance.

(References: NCERT Biology Class 12, Chapter 13)

Population Ecology

• Population growth models:
  • Exponential growth: rapid increase in population size under ideal conditions.
  • Logistic growth: growth slows down as the population approaches carrying capacity.
• Population regulation mechanisms:
  • Density-dependent factors: competition, predation, parasitism, diseases, etc.
  • Density-independent factors: natural disasters, climate changes, etc.
• Life history strategies:
  • r-strategists: high reproductive rate, short lifespan, small body size (e.g., insects).
  • K-strategists: low reproductive rate, long lifespan, large body size (e.g., elephants).
• Survivorship curves: graphical representations of the number of individuals surviving over time.
• Age structure diagrams: graphical representations of the age distribution of a population.
• Reproductive strategies: semelparity (reproduce once and die) vs. iteroparity (reproduce multiple times).

(References: NCERT Biology Class 12, Chapter 14)

Community Ecology

• Community structure: composition and abundance of species in a community.
• Species interactions:
  • Competition: for resources such as food, space, mates.
  • Predation: one species (predator) hunts and consumes another (prey).
  • Mutualism: beneficial relationship between two species.
  • Commensalism: one species benefits while the other is unaffected.
• Ecological succession: sequential changes in the species composition of a community over time.
• Pioneer species: first species to colonize a new habitat.
• Climax community: stable, self-sustaining community that eventually develops.
• Disturbance ecology: role of disturbances (natural and anthropogenic) in shaping communities.
• Invasive species: non-native species that have a negative impact on the ecosystem.

(References: NCERT Biology Class 12, Chapter 15)

Ecosystem Services

• Services provided by ecosystems:
  • Water regulation: control of water flow and quality.
  • Climate regulation: regulation of temperature and precipitation patterns.
  • Pollination: transfer of pollen from one flower to another, essential for plant reproduction.
  • Soil formation and fertility: creation and maintenance of soil, nutrient cycling.
  • Biodiversity: maintenance of genetic diversity and ecological balance.
  • Aesthetic and cultural values: recreation, spiritual significance, etc.
• Economic valuation of ecosystem services: assigning monetary values to the benefits provided by ecosystems.

(References: NCERT Biology Class 12, Chapter 16)

Threats to Biodiversity

• Habitat loss and fragmentation: clearance of forests, urban expansion, road construction.
• Poaching and illegal wildlife trade: hunting and trading of endangered species for their body parts or fur.
• Climate change: altered temperature, precipitation patterns, sea level rise, ocean acidification.
• Pollution: release of harmful substances into the environment, air pollution, water pollution, soil pollution.
• Invasive species: introduction of non-native species that outcompete native species for resources.
• Overexploitation of resources: unsustainable harvesting of resources such as timber, fish, etc.

(References: NCERT Biology Class 12, Chapter 17)

Conservation:

• Conservation Strategies:
  • In-situ conservation:
    • Protected areas: national parks, wildlife sanctuaries, biosphere reserves.
    • Community conservation: involving local communities in conservation efforts.
  • Ex-situ conservation:
    • Seed banks, gene banks, botanical gardens, zoos, aquaria.
• Biodiversity Conservation Acts and Policies:
• Wildlife Protection Act (1972).
• Forest Conservation Act (1980).
• Biodiversity Act (2002).
• National Biodiversity Action Plan (NBAP).
• Ramsar Convention (1971): conservation and wise use of wetlands.
• Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES): regulates the trade of endangered species.
• IUCN Red List: categorized species according to their extinction risk.
• Conservation Success Stories:
• Bengal tiger conservation efforts.
• Asiatic lion conservation efforts.
• Hawaiian monk seal conservation efforts.
• Challenges in Conservation:
• Balancing conservation with economic development.
• Human-wildlife conflict.
• Poaching and illegal wildlife trade.
• Climate change.
• Lack of political will and funding.
• Conservation Education and Awareness:
  • Importance of education in promoting conservation.
  • Raising public awareness about biodiversity and conservation issues.
• Sustainable Development:
  • Integrating conservation into development planning.
  • Sustainable agriculture and forestry practices.
  • Ecotourism.
  • Green technology.
  • Corporate social responsibility.

(References: NCERT Biology Class 12, Chapter 17)