Chapter 52

• Ecology is the scientific study of the interactions between organisms and their

  environment
• Climate is the long-term prevailing weather conditions in an area
• Key components of climate are temperature, precipitation, sunlight, and wind.
• The most significant influence on the distribution of organisms on land

  is climate.
• Paedophryne swiftorum was discovered on a 2008 expedition to Papua New Guinea. At about 8 mm long, it is among the smallest adult vertebrates on earth.
• Global climate patterns are determined largely by the input of solar energy and the Earth’s movement in space.
• Seasonality is the result of Earth’s tilted axis and annual rotation around the sun.
• Cycles in day length, solar radiation, and temperature.
• Precipitation along the equator (wet/dry seasons in the tropics) is an example of a local environmental shift.
• Wind patterns alter ocean currents, causing upwellings of cold water is an example of a local environmental shift.
• Ocean currents influence coastal climates–California Current and Gulf Stream
• Coastal areas are typically wetter than inland areas.
• Coastal climates are moderated by larger bodies of water.
• Mountains affect both rainfall and temperature on their slopes.
• The burning of fossil fuels and deforestation, among other human activities, has led to an increase in atmospheric CO2, and other greenhouse gases.
• Earth has warmed an average of 0.9° C since 1900, and is projected to warm 1-6° more by 2100
• Microclimates are localized patterns in climate conditions.
• A treefall gap in a forest is an example of a microclimate.
• A log or stone sheltering amphibians or invertebrates is an example of a microclimate.
• Large shade trees and open grasses are examples of a microclimate.
• 67 species of the bumblebee in the Northern Hemisphere have shrinking geographic ranges.
• Bumblebee populations are decreasing in size or even disappearing.
• A biome is a major life zone characterized by vegetation in terrestrial biomes, or by the physical environment in aquatic biomes.
• An ecotone is an area of integration between biomes.
• Species composition varies from one location to another within the same kind of biome.
• Convergent evolution can result in structurally similar species.
• Tropical forests

  • warm and wet
  • has diverse plant and animal communities
  • vertically layered
  • human impact: clearcutting, conversion to agriculture
  • soil is nutrient-poor
• Desert

  • 30 degrees lat
  • dry
  • human impact: urbanization, irrigated agriculture
• Savanna

  • equatorial, subequatorial
  • precipitation seasonal
  • fire and drought adapted
  • human impacts: ranching and overhunting
• Chaparral

  • mid-lat coastal regions
  • shrubby
  • precipitation seasonal
  • fire and drought adapted
  • human impact: urbanization and agriculture
• Temperate Grassland

  • precipitation seasonal
  • fire and drought adapted
  • grazers
  • human impact: developed as agricultural land
• Northern Coniferous Forest

  • largest terrestrial biome, extends across northern North America and Eurasia
  • winters are usually cold
  • precipitation: 30-70cm
  • human impact: logging
• Temperate Broadleaf Forest

  • mainly at midlat in the northern hemisphere
  • precipitation year round, 70-200cm
  • human impact: logging, agricultural, development
  • much intact forest no longer exists
• Tundra

  • high elevation at all lats, expansive areas of the arctic
  • covers up to 20% of the Earth's surface
  • dry and cold
  • human impact: mineral and oil extraction
• Aquatic biomes are characterized by their physical and chemical environment.
• Many aquatic biomes are stratified.
• Semi-annual mixing of water (turnover) mixes oxygenated water from the surface with nutrient-rich water from the bottom.
• Oligotrophic lakes are oxygen-rich, but nutrient-poor.
• Eutrophic lakes are oxygen-poor, but nutrient-rich.
• Lakes

  • oligotrophic or eutrophic
  • human impact: human-induced nutrient enrichment leads to algae blooms, oxygen depletion, and fish kills