BIO 2150 Chapter 25 Notes I Carbon A Life on Earth is carbon based 1 Carbon based molecules store and transport energy 2 Carbon forms basic structures of all major biological molecules II Acquiring Carbon A Photosynthetic organisms use solar energy to fix CO2 into sugars 1 6CO2 6H2O C6H12O6 6O2 B Heterotrophic organisms acquire carbon in the form of organic molecules 1 Heterotrophic animals eat other organisms III Short Term Carbon Cycle A Carbon Cycles by means of the complementary processes of photosynthesis and respiration B Photosynthesis rates peak in the northern summer C Respiration stays the same D Respiration releases the most CO2 every year IV The Carbon Cycle A CO2 is added to the atmosphere by 1 Biological imputes 2 Volcanoes mid ocean ridges 3 Human Activities B CO2 is removed from the atmosphere by 1 Geological removal chemical weathering 2 Biological processes Photosynthesis C Most of Earth s carbon is found in sedimentary rocks V How Does Carbon Cycle in and out of Rocks A Weathering sedimentary rocks ocean rocks B Carbonate precipitation ocean water marine sediments C Organic matter burial biomass sediments D Volcanism sedimentary rocks atmosphere E Seduction ocean sediments magma VI The Long Term Carbon Cycle A The amount of atmospheric CO2 has changed 1 It has dropped 10 20 fold or more since the Cambrian Period 2 Cyclically fluctuated over the past 400 000 years 3 Increased 25 in the past 50 years B Carbon isotope studies show that the source of increased carbon is human activity C Cycles of CO2 levels correlate with glaciation events D Atmospheric O2 levels tend to move opposite of CO2 levels due to photosynthesis and respiration balance VII Food Web A Carbon enters the food web through primary producers B Carbon passed through the food web from primary producers to consumers to decomposers to the environment C Some CO2 is lost at each level D Energy cycles through the food web from primary producers to consumers to decomposers E Some energy is lost at each level as heat F Trophic pyramids show what happens to energy or carbon from level to level G Biological activity has a major impact on the carbon cycle 1 Evolution of Photosynthesis 2 Organisms increased the rates of weathering and formation of soils 3 Bio mineralization shell formation 4 Evolution of decomposition of resistant woody plants resulted in increased carbon into the biomass and drop in CO2 levels
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