Ch11 Biogeography

Chapter 11: Biogeography

Ecosystems

  • Definition: Groups of organisms occupying a given area functioning together with their nonliving environment.

    • Microecosystems: Small ecosystems with shared characteristics.

    • Open Systems: Movement of both energy and matter into and out of the ecosystem.

Ecosystem Components

Abiotic Components (Nonliving)

  • Features:

    • Physical environment influencing organisms.

    • Includes:

      • Sunlight

      • Wind

      • Rain

      • Soil

      • Water

      • Nutrients

      • Heat

      • Gases

Biotic Components (Living)

  • Producers:

    • Organisms that produce food from light energy.

    • Examples: Plants, algae.

  • Consumers:

    • Herbivores and carnivores that obtain energy by consuming other organisms.

    • Decomposers:

    • Organisms like fungi and bacteria that break down dead materials.

Trophic Structure

  • Food Chain: Hierarchical series showing energy flow.

  • Trophic Levels:

    • Producers (1st Level): Trees, shrubs, and grass.

    • Primary Consumers (2nd Level): Herbivores like locusts, rabbits.

    • Secondary Consumers (3rd Level): Carnivores such as praying mantis.

    • Tertiary Consumers (4th Level): Larger carnivores like owls and coyotes.

    • Decomposers (Last Level): Fungi and bacteria.

Energy Flow and Biomass

  • Biomass: The total amount of living material in an ecosystem.

  • High biomass indicates high biodiversity.

    • Example: Discussion about Utah's biomass.

Primary and Secondary Productivity

  • Net Primary Productivity (NPP):

    • Energy stored by plants after losses from metabolism.

    • Metric for measuring productivity levels.

  • Primary Productivity:

    • Organic matter produced by autotrophs during photosynthesis.

  • Secondary Productivity:

    • Organic matter produced by heterotrophs.

Factors Affecting Primary Productivity

  1. Sunlight (daylength and solar angle)

  2. Latitude

  3. Soil Moisture

  4. Temperature

  5. Nutrients

  6. Age of Ecosystem

  7. Atmospheric Composition

Ecological Niche

  • Habitat: The physical location where an organism lives.

    • Niche: The role of the organism in the ecosystem.

    • Types of Niches:

      • Generalists: Adapt to a wide range of conditions.

      • Specialists: Adapted to specific environmental conditions.

Succession and Climax Communities

  • Succession: The process by which ecosystems change over time.

    • Types:

      • Primary Succession: Begins in lifeless areas (e.g., bare rock).

      • Secondary Succession: Follows disturbances (e.g., after a fire).

  • Stages:

    • Pioneer Species: The first to colonize previously disrupted or damaged ecosystems.

    • Intermediate Species: Replace pioneer species as conditions change.

    • Climax Community: Stable communities that result after extensive succession.

Environmental Controls

  • Ecotone: Transitional area between different ecosystems.

  • Biomes: Major types of terrestrial ecosystems characterized by climate, temperature, and precipitation niches.

Human Impact on Ecosystems

  • Consequences of human activity:

    • Land degradation

    • Desertification

    • Wetland destruction

Classification of Terrestrial Ecosystems

  • Forest Biomes:

    • Includes tropical rainforest, broadleaf deciduous, and coniferous forests.

  • Grassland Biomes:

    • Includes tropical savanna and tall-grass prairie.

  • Desert Biome:

    • Characterized by extremely low moisture.

Marine Ecosystems

  • Types:

    • Plankton: Smallest aquatic organisms (phytoplankton and zooplankton).

    • Nekton: Swimming organisms.

    • Benthos: Organisms living on or in the ocean floor.

Resilience of Life Forms

  • History of Life:

    • First life forms appeared 3.8 billion years ago (anaerobic bacteria).

    • Autotrophs emerged around 2 billion years ago followed by heterotrophs.

    • Modern humans evolved roughly 200,000 years ago.

  • Climate Factors: Control the distribution of life forms around the globe.