Biology 2483A Lecture Notes - Lecture 21: Great Oxygenation Event, Nutrient Cycle, Soil Ph
28 Nov 2017
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Topic: nutrient supply and cycling: chemical breakdown of minerals in rocks or through fixation of atmospheric gases. Oxygen, carbon, hydrogen and nitrogen make up a substantial amount of dry mass. Silicon is very important structurally in plants, and also important in bone development: glass sponge: made of silica. All organisms have similar nutrient requirements, but amounts and specific nutrients needed vary. An organism"s nutrient requirements are related to its physiology mode of energy acquisition (autotrophic or heterotrophic), mobility, thermal physiology (endotherm or ectotherm) All nutrients are ultimately derived from abiotic sources: gases in the atmosphere. Oxygen appeared 2. 4 billion years ago, origin of chloroplast. Ocean cyanobacteria (2. 3 billion years ago) caused the great oxygenation event: oxygen was added to the atmosphere because of the cyanobacteria, origin of chloroplast. Atmosphere is like a pump, it unlocked more nutrients from precipitation. Detritus is a very important pool for the soluble nutrients: minerals in rocks.
