Biomes and Climate

Biomes and Climate

Key Concepts

  • Biosphere: Encompasses global processes.
  • Ecosystem: Involves energy flux and nutrient cycling.
  • Community: Focuses on interactions among populations.
  • Population: Dynamics of populations; considered the unit of evolution.
  • Organism: Survival and reproduction; the unit of natural selection.

Climate vs. Weather

  • Weather: Atmospheric conditions over short periods.
  • Climate: Long-term average atmospheric conditions (e.g., precipitation, temperature) over large regions.
  • Earth’s Climate Influences:
    1. Sun: Provides solar radiation; angle affects temperature and seasonal changes.
    2. Atmosphere: Insulates Earth and maintains stable surface temperatures through air movements (winds).
    3. Oceans: Store and transport heat/moisture, influencing regional climates through surface currents.
    4. Topography: Affects precipitation and local climates; rain shadow effect shows how mountains influence moisture distribution.

Biomes Definition

  • Biomes are broad geographic areas with similar climates and communities of species.
  • Organisms in a biome adapt to similar climate conditions over time.
  • The distribution and nature of biomes are influenced by climate as well as biotic and abiotic factors.

Types of Biomes

  1. Terrestrial Biomes: 10 major types characterized by climate, specifically temperature and precipitation.
    • Typical classifications include:
      • Tundra
      • Desert
      • Boreal Forest (Taiga)
      • Deciduous Forest
      • Grasslands
      • Savanna
      • Tropical Rainforest
  2. Aquatic Biomes: 2 major types (Freshwater and Saltwater) that cover most of Earth’s surface.
    • Freshwater: Lakes, rivers (less than 1% salinity).
    • Saltwater: Oceans and estuaries (~3% salinity).

Aquatic Biome Structures

  • Stratified into zones based on:
    1. Light penetration
    2. Nutrient levels
    3. Oxygen availability

Productivity in Ecosystems

  • Productivity: Rate of biomass generation in an ecosystem.
    • Primary Productivity: Specifically refers to rates by photoautotrophs (photosynthesis).
  • Limitations on Productivity:
    • Aquatic ecosystems: Light and nutrient availability.
    • Terrestrial ecosystems: Water availability.

Nutrient Availability & Ecosystem Carrying Capacity

  • Nutrients are essential for survival with macronutrients (e.g., carbon, nitrogen, phosphorus) needed in larger amounts and micronutrients needed in smaller amounts.
  • Liebig’s Law of the Minimum: Indicates that one limiting resource can determine the ecosystem's carrying capacity.

Global Patterns of Productivity

  1. Land:
    • Warm, wet climates near the equator support forests with high productivity.
    • Cold, dry climates have limited productivity.
  2. Oceans:
    • High productivity along coastal margins due to nutrient runoff from continents.

Species Diversity and Climatic History

  • Latitudinal Diversity Gradient: Species diversity peaks near the equator, decreasing towards the poles.
  • Tropical biomes are older and more stable than biomes at higher latitudes, which have changed more due to climatic shifts.

Summary Points

  • Climate significantly influences the primary production across land and water ecosystems.
  • Understanding biomes and climate interactions is crucial for ecological studies and conservation efforts.