Ecology + Biosphere

Levels of Ecological Research

  • organismal (like Hunt studying fruit flies and evolution)

  • population (organisms of same species in the same area)

  • community (group of populations in the same area, like how rattlesnake populations interact w/ mice)

  • ecosystem (community + physical factors they interact with)

  • landscape (mosaic of ecosystems)

  • biomes (type of landscape)

  • biosphere


Climate = long term weather conditions

  • macroclimate = global/larger scale, microclimate = specific location

  • 4 main factors:

    1. Sunlight + Earth’s movement in space→ drives differences in temperature, air movement, and water cycle

    2. Precipitation

      1. Tropics: water evaporates→ warm, wet air towards poles

      2. Rising air masses: released water→ high precipitation (often in tropics)

      3. Dry, descending air masses: arid climates (near 30 degrees north and south)

    3. Wind- wind belts globally

      1. Earth rotates→ land near equator moves faster than at the poles

      2. Cooling trade winds blow east to west (Tropics)

      3. Prevailing westerlies blow west to east (Temperate zones)

    4. Temperatures

      1. directly affects biological processes→ metabolism, growth, survival

      2. driven by solar radiation (sunlight)

      3. varies w/ time of days, seasons, microclimate scale like being in shade


Seasonality- only present in mids to high latitudes

  • high latitudes (near poles) seasonality due to tilt of Earth’s axis, and annual passage around sun

  • Day length diff b/w winter and summer solstice can vary more in northern areas than in south, even in the continental US

  • Small aquatic environments- temperate lakes are layered

    • surface water w/ lots of oxygen, nutrient-rich area at bottom

    • turnover in spring and water→ reoxygenation and temperature differences


Biomes- major lifezones characterized by physical environment

  • terrestrial biomes strongly influenced by temperature and precipitation

  • aquatic zones influenced by light penetration and depth from bottom

Species distributions- result of ecology and evolutionary history, impacted by climate and species history