Introduction to Ecology

Introduction to Ecology

  • Definition of Ecology:

    • Study of interactions between organisms and their environment.
    • Involves both biotic (living) and abiotic (non-living) factors.

  • Distinguishing Ecology:

    • Not synonymous with environmentalism, natural history, or environmental science.
    • Ernst Haeckel introduced the term 'ecology' in 1866.

Levels of Ecological Study

  • Ecological Hierarchy:
    • Organismal Ecology: Study of individual organisms.
    • Population Ecology: Study of populations of the same species.
    • Community Ecology: Study of interactions between different species within a community.
    • Ecosystem Ecology: Study of interactions between communities and their environment.
    • Landscape Ecology: Study of different ecosystems and their arrangement.
    • Global Ecology: Study of interactions on a planetary scale.

Key Concepts in Ecology

  • Biogeography:

    • Study of the geographic distribution of organisms.
    • Determines abundance and distribution of species.

  • Dispersal:

    • Movement of individuals away from centers of population density.
    • Essential for understanding how species occupy certain areas.

  • Exotic & Invasive Species:

    • Exotic species: Non-native species introduced to an area.
    • Invasive species: Rapidly spreading exotic species that disrupt local ecosystems.

Factors Affecting Distribution and Abundance

  • Abiotic Factors:

    • Non-living components affecting distribution:
    • Water, sunlight, temperature, soil nutrients, pH, wind, salinity.

  • Biotic Factors:

    • Living components affecting distribution:
    • Interactions with other organisms, predation, competition.

  • Interaction of Biotic and Abiotic Factors:

    • Species distribution often a result of interactions between abiotic conditions and biotic influences.

Climate and its Impact on Ecosystems

  • Climate Components:

    • Temperature, water, sunlight, wind.
    • Long-term weather patterns influence the types of ecosystems found in certain areas.

  • Microclimate vs. Macroclimate:

    • Macroclimate: Patterns at larger scales (regional or global).
    • Microclimate: Fine-scale variations (e.g., under a log).

  • Seasonal Variations:

    • Seasonal changes in light and temperature affect ecosystem dynamics and the distribution of organisms.

Major Terrestrial Biomes

  • Types of Terrestrial Biomes:
    • Tundra, boreal forest (taiga), temperate forest, temperate grassland, tropical forest, deserts, savannas, and chaparrals.
  • Biome Characteristics:
    • Defined by climate conditions, primarily temperature and precipitation.
    • Each biome supports distinct communities of plants and animals.

Net Primary Productivity (NPP)

  • Definition of NPP:
    • Total biomass produced yearly after accounting for energy used in respiration.
  • Implications for Ecosystems:
    • Determines the available energy for higher trophic levels, influenced by climate factors.

Aquatic Biomes

  • Key Physical Factors:

    • Salinity, water depth, nutrient availability, water flow.

  • Zones in Aquatic Environments:

    • Intertidal, neritic, oceanic, benthic, photic, and aphotic zones.

  • Freshwater vs. Marine Biomes:

    • Freshwater includes lakes, ponds, wetlands, and streams.
    • Marine includes oceans, estuaries, coral reefs, and coastal regions.

Human Impacts on Ecology

  • Human Alteration of Biomes:

    • Over 75% of land has been significantly altered by human activities.
    • Issues such as invasive species, pollution, and climate change impact ecosystems and species distributions.

  • Conservation Biology:

    • Integrates ecological principles to address species preservation and ecosystem restoration.