GEOG 1220 Lecture Notes - Bioaccumulation, Oxygen Cycle, Ecological Pyramid
2 Apr 2013
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Document Summary
Availability of energy and matter are highly variable from place to place and account for the diversity of life on earth. Limiting factors = physical, chemical and biological characteristics that restrain population growth : for example, plant productivity (e. g. photosynthesis) is limited by the requirement in least supply, environmental resistance = all limiting factors taken together. Nutrients = elements and compounds required for survival that are consumed by organisms: sedimentary cycles: nutrients spend much of their time locked up in rock but are released for use by life as a result of weathering processes. Examples: calcium, phosphorous: gaseous cycle: nutrients spend much of their time in the atmosphere. Nutrients are exchanged between the biosphere and the atmosphere. It can then be used by living things and then a demystification cycle occurs. Heat makes nitrogen organic (being struck my lightning) We"ve added a lot of nitrogen to the earth from fertilizers.
