position of a group of organisms in a International-mindedness: community that occupy the same position Ecosystems such as lakes and forests in food chains. can exist across political boundaries. Producers (autotrophs) are typically plants or algae that produce their own Theory of knowledge: food using photosynthesis and form the first trophic level in a food chain. Feeding relationships can be Exceptions include chemosynthetic represented by different models—how organisms that produce food without can we decide when one model is better sunlight. than another? Feeding relationships involve producers, consumers and decomposers. These can Connections: be modelled using food chains, food ESS: Energy and equilibria (1.3); webs and ecological pyramids. sustainability (1.4); climate Ecological pyramids include pyramids of causes and impacts (7.2); water pollution numbers, biomass and productivity and (4.4); terrestrial food production systems are quantitative models that are usually and food choices (5.2); biodiversity and measured for a given area and time. conservation (topic 3) In accordance with the second law of Diploma Program: Biology (topics 4 and thermodynamics, there is a tendency for 9; option C) numbers and quantities of biomass and energy to decrease along food chains; therefore, the pyramids become narrower towards the apex. Bioaccumulation is the build-up of persistent or non-biodegradable pollutants within an organism or trophic level because they cannot be broken down. Biomagnification is the increase in concentration of persistent or pollutants along a food chain. Toxins such as DDT and mercury accumulate along food chains due to the decrease of biomass and energy.
position of a group of organisms in a community that occupy the same position in food chains. Producers (autotrophs) are typically plants or algae that produce their own food using photosynthesis and form the first trophic level in a food chain. Exceptions include chemosynthetic organisms that produce food without sunlight. Feeding relationships involve producers, consumers and decomposers. These can be modelled using food chains, food webs and ecological pyramids. Ecological pyramids include pyramids of numbers, biomass and productivity and are quantitative models that are usually measured for a given area and time. In accordance with the second law of thermodynamics, there is a tendency for numbers and quantities of biomass and energy to decrease along food chains; therefore, the pyramids become narrower towards the apex. Bioaccumulation is the build-up of persistent or non-biodegradable pollutants within an organism or trophic level because they cannot be broken down. Biomagnification is the increase in concentration of persistent or pollutants along a food chain. Toxins such as DDT and mercury accumulate along food chains due to the decrease of biomass and energy. International-mindedness: Ecosystems such as lakes and forests can exist across political boundaries. Theory of knowledge: Feeding relationships can be represented by different models—how can we decide when one model is better than another? Connections: ESS: Energy and equilibria (1.3); sustainability (1.4); climate and impacts (7.2); water pollution (4.4); terrestrial food production systems and food choices (5.2); biodiversity and conservation (topic 3) Diploma Program: Biology (topics 4 and 9; option C) causes
IB_Environmental_Systems_and_Societies_2016.docx