The second law of thermodynamics A tipping point is the minimum amount of explains the inefficiency and decrease in change within a system that will available energy along a food chain and destabilize it, causing it to reach a new energy generation systems. equilibrium or stable state. As an open system, an ecosystem will Examples of human impacts and normally exist in a stable equilibrium, possible tipping points should be either in a steady-state equilibrium or in explored. one developing over time (for example, International-mindedness: succession), and maintained by stabilizing negative feedback loops. The use of energy in one part of the Negative feedback loops (stabilizing) globe may lead to a tipping point or time occur when the output of a process lag that influences the entire planet’s inhibits or reverses the operation of the ecological equilibrium. same process in such a way as to reduce change—it counteracts deviation. Theory of knowledge: Positive feedback loops (destabilizing) will tend to amplify changes and drive the The laws of thermodynamics are system towards a tipping point where a examples of scientific laws—in which new equilibrium is adopted. ways do scientific laws differ from the The resilience of a system, ecological or laws of human science subjects, such as social, refers to its tendency to avoid economics? such tipping points and maintain stability. Connections: Diversity and the size of storages within systems can contribute to their resilience ESS: Systems and models (1.2); and affect their speed of response to communities and ecosystems (2.2); change (time lags). terrestrial food production systems and Humans can affect the resilience of food choices (5.2); energy choices and systems through reducing these storages security (7.1) and diversity. DP: Physics (topic 2 and option B); The delays involved in feedback loops chemistry (topics 5, 7 and 15; option C); make it difficult to predict tipping points biology (topic 6); design technology and add to the complexity of modelling (topic 2) systems. Applications and skills:
The second law of thermodynamics explains the inefficiency and decrease in available energy along a food chain and energy generation systems. As an open system, an ecosystem will normally exist in a stable equilibrium, either in a steady-state equilibrium or in one developing over time (for example, succession), and maintained by stabilizing negative feedback loops. Negative feedback loops (stabilizing) occur when the output of a process inhibits or reverses the operation of the same process in such a way as to reduce change—it counteracts deviation. Positive feedback loops (destabilizing) will tend to amplify changes and drive the system towards a tipping point where a new equilibrium is adopted. The resilience of a system, ecological or social, refers to its tendency to avoid such tipping points and maintain stability. Diversity and the size of storages within systems can contribute to their resilience and affect their speed of response to change (time lags). Humans can affect the resilience of systems through reducing these storages and diversity. The delays involved in feedback loops make it difficult to predict tipping points and add to the complexity of modelling systems. Applications and skills: A tipping point is the minimum amount of change within a system that will destabilize it, causing it to reach a new equilibrium or stable state. Examples of human impacts and possible tipping points should be explored. International-mindedness: The use of energy in one part of the globe may lead to a tipping point or time lag that influences the entire planet’s ecological equilibrium. Theory of knowledge: The laws of thermodynamics are examples of scientific laws—in which ways do scientific laws differ from the laws of human science subjects, such as economics? Connections: ESS: Systems and models (1.2); communities and ecosystems (2.2); terrestrial food production systems and food choices (5.2); energy choices and security (7.1) DP: Physics (topic 2 and option B); chemistry (topics 5, 7 and 15; option C); biology (topic 6); design technology (topic 2)
IB_Environmental_Systems_and_Societies_2016.docx