World Communities

• heat is distributed via oceanic and atmospheric currents
• atmospheric cells

  A) polar cell

  B) ferrel cell

  C) hadley cell

  
• El Nino


  trade winds weaken, warm water pushed east, making northern US and Canada are dryer
• La Nina


  cold event, strong trade winds, warm water pushed towards Asia
• terrestrial biomes


  a climatically and geographically defined area of ecologically similar communities of plants, animals, and soil organisms
• ecosystem


  dynamic complexes of plant, animal and micro-organism communities and their non-living (abiotic) environment interacting as a functional unit
• types of terrestrial biomes 


  tropical rainforests, savanna, deciduous forest, coniferous forests, deserts, grasslands, Mediterranean scrub, taiga, tundra
• tropical rainforests have high rainfall and temperature
• savannas have seasonal draught and high temperature
• deserts have low precipitation but a wet season
• grasslands have a moderate temperature and precipitation
• conifer forests have moderate temperature and rainfall
• taigas have low precipitation and temperature
• rainforests have broad evergreen trees, epiphytes, and lianas
• savannas have grasslands with scattered broad deciduous shrubs and trees
• deserts have succulents and some annual herbs
• grasslands have perennial and sod grasses
• conifers forests can have a mix of broadleaf and conifers
• Mediterranean scrub have evergreens, summer deciduous, and shrubs/thicket
• taigas have largely coniferous forests
• tundras have very low shrubs, grasses, and lichens
• rainforest soils are infertile and the species diversity is very high
• savannas have common periodic fires, C4 photosynthesis
• C4 photosynthesis 


  four carbon compound is used and create a bundle around Rubisco, helping them retain water
• desert plants have thick waxy cuticle, hairy epidermis, and use the CAM photosynthesis
• CAM photosynthesis


  crassulacean acid metabolism, stomata open at night and stores CO2 for daytime use
• grasslands are the largest biome but have been heavily replaced with agriculture
• conifer forests transition between temperate and taiga and can have infertile soil
• deciduous forest vegetation vary with season
• taiga soils are acidic and infertile with possible permafrost
• tundras have permafrost preset in soils with plant biomass below the ground
• topography can have similar effect like that of latitude with altitude
• massenerhebung effect


  variation in tree line based on mountain size and location due to wind shadowing and heat retention
• high thermal capacity of water makes oceans slow to heatand slow to cool
• most of ocean experiences homogeneity expect on coastlines
• aquatic biomes


  rivers, lakes, pelagic, ocean benthic, inter-tidal zone, coral reefs, estuaries, wet lands
• rivers contain 0.006% of world's water and yet they are the most utilised
• rivers always interact with terrestrial environment through drainage basins
• rivers have a unidirectional flow which allows the set up of gradients
• oxygen concentration is high in turbulent, upstream, and lower down rivers