Students should understand the link conversion of light energy to between sustainable yields and chemical energy productivity. transfer of chemical energy from Values for GPP and NPP should be one trophic level to another with compared from various biomes. varying efficiencies The term is sometimes “assimilation” overall conversion of ultraviolet used instead of “secondary productivity”. and visible light to heat energy by The roles of calcification, sedimentation, an ecosystem lithification, weathering and volcanoes in re-radiation of heat energy to the the carbon cycle are not required. atmosphere. Detailed knowledge of the role of The conversion of energy into biomass bacteria in nitrogen fixation, nitrification for a given period of time is measured as and ammonification is not required. productivity. International-mindedness: Net primary productivity (NPP) is calculated by subtracting respiratory Human impacts on the flows of energy losses (R) from gross primary and matter occur on a global scale. productivity (GPP). NPP = GPP R – Theory of knowledge: Gross secondary productivity (GSP) is the total energy or biomass assimilated The energy drives energy flows, Sun’s by consumers and is calculated by and throughout history there have been subtracting the mass of fecal loss from about the importance of the “myths” the mass of food consumed. Sun—what role can mythology and GSP = food eaten fecal loss – anecdotes play in the passing on of Net secondary productivity (NSP) is scientific knowledge? calculated by subtracting respiratory Connections: losses (R) from GSP. NSP = GSP R – ESS: Introduction to the atmosphere Maximum sustainable yields are (6.1); introduction to water systems (4.1); equivalent to the net primary or net introduction to soil systems (5.1); human secondary productivity of a system. population carrying capacity (8.4) Matter also flows through ecosystems Diploma Program: Biology (topics 4 and linking them together. This flow of matter 9; option C); chemistry (option C); involves transfers and transformations.
conversion of light energy to chemical energy transfer of chemical energy from one trophic level to another with varying efficiencies overall conversion of ultraviolet and visible light to heat energy by an ecosystem re-radiation of heat energy to the atmosphere. The conversion of energy into biomass for a given period of time is measured as productivity. Net primary productivity (NPP) is calculated by subtracting respiratory losses (R) from gross primary productivity (GPP). NPP = GPP – R Gross secondary productivity (GSP) is the total energy or biomass assimilated by consumers and is calculated by subtracting the mass of fecal loss from the mass of food consumed. GSP = food eaten – fecal loss Net secondary productivity (NSP) is calculated by subtracting respiratory losses (R) from GSP. NSP = GSP – R Maximum sustainable yields are equivalent to the net primary or net secondary productivity of a system. Matter also flows through ecosystems linking them together. This flow of matter involves transfers and transformations. Students should understand the link between sustainable yields and productivity. Values for GPP and NPP should be compared from various biomes. The term “assimilation” is sometimes used instead of “secondary productivity”. The roles of calcification, sedimentation, lithification, weathering and volcanoes in the carbon cycle are not required. Detailed knowledge of the role of bacteria in nitrogen fixation, nitrification and ammonification is not required. International-mindedness: Human impacts on the flows of energy and matter occur on a global scale. Theory of knowledge: The Sun’s energy drives energy flows, and throughout history there have been “myths” about the importance of the Sun—what role can mythology and anecdotes play in the passing on of scientific knowledge? Connections: ESS: Introduction to the atmosphere (6.1); introduction to water systems (4.1); introduction to soil systems (5.1); human population carrying capacity (8.4) Diploma Program: Biology (topics 4 and 9; option C); chemistry (option C);