biodiversity topic 4 overview

1. Biodiversity

  • Definition: The variety of life on Earth, encompassing all organisms, species, ecosystems, and genetic diversity.

  • Levels of Biodiversity:

    1. Genetic Diversity: Variation in genes within a species (e.g., different dog breeds).

    2. Species Diversity: Variety of species in an ecosystem or on Earth (e.g., mammals, insects).

    3. Ecosystem Diversity: Range of different habitats, communities, and ecosystems in an area.

  • Importance:

    • Supports ecosystem services like pollination, nutrient cycling, and climate regulation.

    • Provides resources like food, medicine, and raw materials.

    • Maintains ecosystem resilience to disturbances.

2. Biological Classification

  • Definition: The systematic grouping of organisms based on shared characteristics.

  • Taxonomy:

    • The hierarchical system: Domain → Kingdom → Phylum → Class → Order → Family → Genus → Species.

    • Mnemonic: "Dear King Philip Came Over For Good Soup."

  • Domains:

    1. Bacteria: Single-celled prokaryotes, no nucleus.

    2. Archaea: Single-celled, prokaryotic, often extremophiles.

    3. Eukarya: Organisms with complex cells (e.g., plants, animals, fungi, protists).

  • Binomial Nomenclature:

    • Developed by Carl Linnaeus.

    • Each species has a two-part Latin name (Genus species, e.g., Homo sapiens).

3. Adaptations

  • Definition: Traits that improve an organism's ability to survive and reproduce in a specific environment.

  • Types:

    1. Structural Adaptations: Physical features (e.g., camels’ humps store fat for water conservation).

    2. Behavioral Adaptations: Behaviors that improve survival (e.g., birds migrating).

    3. Physiological Adaptations: Internal body processes (e.g., desert plants storing water in thick stems).

  • Natural Selection:

    • Proposed by Charles Darwin.

    • Organisms better adapted to their environment survive and reproduce, passing on advantageous traits.

4. Ecosystem Diversity

  • Definition: The variety of ecosystems in a given region (e.g., forests, deserts, wetlands).

  • Ecosystems: Communities of living organisms (biotic factors) interacting with their non-living environment (abiotic factors like air, water, and soil).

  • Biomes: Large ecosystems classified by climate, vegetation, and animal life (e.g., tundra, rainforest).

  • Ecosystem Services:

    1. Provisioning Services: Resources like food, water, and wood.

    2. Regulating Services: Climate regulation, pollination.

    3. Cultural Services: Recreational, spiritual, and aesthetic benefits.

    4. Supporting Services: Nutrient cycling and soil formation.

5. Energy and Matter in an Ecosystem

  • Energy Flow:

    • Producers (Autotrophs): Organisms like plants and algae that use sunlight (photosynthesis) or chemicals (chemosynthesis) to make food.

    • Consumers (Heterotrophs): Organisms that consume other organisms for energy.

      • Primary Consumers: Herbivores (e.g., rabbits).

      • Secondary Consumers: Carnivores that eat herbivores (e.g., snakes).

      • Tertiary Consumers: Top predators (e.g., hawks).

    • Decomposers: Fungi and bacteria that recycle nutrients by breaking down dead organisms.

    • Trophic Levels: The hierarchical levels of energy flow (only ~10% of energy transfers to the next level).

  • Matter Cycling:

    • Carbon Cycle: Photosynthesis and respiration cycle carbon.

    • Nitrogen Cycle: Nitrogen fixation and decomposition make nitrogen accessible to plants.

    • Water Cycle: Evaporation, condensation, and precipitation.

6. Niche and Keystone Species

Niche:

  • Definition: The role and position of a species within its environment, including its habitat, resource use, and interactions.

  • Fundamental Niche: The potential range of conditions a species can tolerate.

  • Realized Niche: The actual conditions a species occupies due to competition.

Keystone Species:

  • Definition: A species with a disproportionately large impact on its ecosystem relative to its abundance.

  • Examples:

    • Wolves in Yellowstone: Regulate prey populations, indirectly affecting vegetation and other species.

    • Sea Otters: Control sea urchin populations, protecting kelp forests.

7. Ecosystem Change Over Time

  • Ecological Succession:

    • Primary Succession: Occurs in lifeless areas (e.g., volcanic lava fields). Pioneer species like lichens colonize first.

    • Secondary Succession: Follows a disturbance (e.g., forest fire) where soil remains.

    • Climax Community: A stable, mature ecosystem at the end of succession.

  • Disturbances:

    • Natural: Hurricanes, wildfires.

    • Anthropogenic: Deforestation, urbanization.

8. Human Impact on Ecosystems

  • Deforestation: Reduces biodiversity and disrupts carbon and water cycles.

  • Pollution:

    • Air Pollution: Greenhouse gases contribute to climate change.

    • Water Pollution: Eutrophication from fertilizers harms aquatic ecosystems.

  • Climate Change: Alters habitats, leading to species migration or extinction.

  • Overexploitation: Overfishing and hunting deplete species populations.

  • Habitat Destruction: Urbanization and agriculture fragment ecosystems.

  • Invasive Species: Non-native species disrupt ecosystems (e.g., cane toads in Australia).

  • Conservation Efforts:

    • Protected Areas: National parks and wildlife reserves.

    • Sustainable Practices: Reducing resource use, reforestation.

    • Endangered Species Protection: Laws like the Endangered Species Act.

  • Restoration Ecology: Repairing damaged ecosystems.

  • 1. Biotic Factors

    • Definition: The living components of an ecosystem.

    • Examples:

      1. Producers (Autotrophs):

        • Plants, algae, and some bacteria that produce energy through photosynthesis or chemosynthesis.

      2. Consumers (Heterotrophs):

        • Herbivores, carnivores, omnivores, and detritivores (e.g., cows, lions, humans, earthworms).

      3. Decomposers:

        • Organisms like fungi and bacteria that break down dead organic matter, recycling nutrients.

      4. Interactions:

        • Predation: One organism (predator) hunts and eats another (prey).

        • Competition: Organisms vie for the same resources (e.g., food, water, territory).

        • Symbiosis:

          • Mutualism: Both species benefit (e.g., bees and flowers).

          • Commensalism: One benefits, the other is unaffected (e.g., barnacles on whales).

          • Parasitism: One benefits at the other's expense (e.g., ticks on a dog).

    2. Abiotic Factors

    • Definition: The non-living components of an ecosystem that influence living organisms.

    • Examples:

      1. Climate:

        • Temperature: Affects metabolism and distribution of organisms.

        • Precipitation: Determines water availability.

        • Sunlight: Drives photosynthesis and influences plant growth.

      2. Soil:

        • Nutrient content, texture, and pH affect plant growth.

      3. Water:

        • Availability, salinity, and quality are critical for aquatic and terrestrial organisms.

      4. Air:

        • Oxygen and carbon dioxide levels impact respiration and photosynthesis.

      5. Geographical Features:

        • Altitude, latitude, and terrain shape habitats.

      6. Chemical Factors:

        • pH, minerals, and dissolved nutrients in water and soil.

    3. Interactions Between Abiotic and Biotic Factors

    Abiotic and biotic factors are interdependent:

    • Abiotic factors shape biotic communities:

      • A desert's arid climate supports drought-tolerant plants like cacti.

      • A rainforest's high rainfall and warm temperatures support diverse species.

    • Biotic factors can modify abiotic conditions:

      • Trees (biotic) provide shade, lowering soil temperatures (abiotic).

      • Earthworms (biotic) aerate and enrich soil, altering its composition (abiotic).

    4. Importance of Balance

    • Ecosystems function optimally when biotic and abiotic factors are in balance.

    • Changes to abiotic factors (e.g., climate change, pollution) can disrupt ecosystems, affecting the biotic components.