Ecology Overview

Introduction to Ecology

  • Definition: Ecology is the study of interactions between organisms and their environment.
  • Key Questions: What determines the distribution and abundance of organisms?

Levels of Ecological Study

  • 1. Organismal Ecology:

    • Focus: Interactions between individuals and their environments.
    • Example: Sockeye salmon migrate from saltwater to freshwater to breed.

  • 2. Population Ecology:

    • Focus: Changes in population size over space and time.
    • Example: Each female salmon produces thousands of eggs; very few survive to maturity.

  • 3. Community Ecology:

    • Focus: Interactions among species and their consequences.
    • Example: Salmon are both prey and predators in their ecosystems.

  • 4. Ecosystem Ecology:

    • Focus: Energy flow and nutrient cycling in the environment.
    • Example: Salmon decompose after death, releasing nutrients into the ecosystem.

  • 5. Global Ecology:

    • Focus: Global changes and their effects on the biosphere.
    • Example: Climate change affects salmon populations worldwide.

Population Viability and Conservation Biology

  • Population Viability: Analyzing factors influencing population stability and size.

    • Stochasticity: Random variations affecting populations.
    • Triage Concept: Evaluating which populations need more help.
    • Minimum Viable Population: Number of individuals necessary to ensure long-term survival.

  • Conservation Goals:

    • Protect critical habitats and manage reserve networks.
    • Address issues with invasive species and biodiversity.

Distribution of Species and Factors

  • Factors Influencing Distribution:

    • Biotic Factors: All living factors (predation, competition, etc.)
    • Abiotic Factors: Non-living factors (temperature, light, water, etc.)

  • Questions to Consider:

    • Does dispersal limit distribution?
    • Are areas accessible?
    • Do abiotic factors restrict distribution?

Global Climate Patterns

  • Solar Intensity: Variations caused by the Earth's curvature affect species distribution by latitude.
  • Jet Streams and Winds:
    • Global air circulation impacts precipitation patterns and climate zones.

Oceanic and Tidal Dynamics

  • Tidal Movements:

    • Types: Semidiurnal, diurnal, and mixed tides.

  • Upwelling:

    • Wind pushes surface water away, allowing rich nutrient waters to rise.

Chemical Factors Influencing Distribution

  • Water Quality: Essential for species survival includes levels of:
    • Oxygen, salinity, pH, and nutrients.
  • Physical Factors: Temperature, moisture, light availability, and soil structure affect habitats.