ESS (IBDP) 1.3 energy and energy and equilibria unit of work

Entire unit of work for Environmental systems and societies topic 1.3: energy and equilibria. Full lessons ready to teach: no extra planning needed.

Covers:

The first law of thermodynamics is the principle of conservation of energy,
which states that energy in an isolated system can be transformed but cannot
be created or destroyed.
• The principle of conservation of energy can be modelled by the energy
transformations along food chains and energy production systems.
• The second law of thermodynamics states that the entropy of a system
increases over time. Entropy is a measure of the amount of disorder in a
system. An increase in entropy arising from energy transformations reduces
the energy available to do work.
• The second law of thermodynamics explains the in efficiency 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.