Practise HL questions by analysing steady-state balance, population recovery and resilience, then evaluating whether equilibrium supports ecological sustainability.
Steady state equilibrium is a concept relevant to many systems. Justify its usefulness in understanding the sustainability of named systems.
Answers may demonstrate:
- understanding concepts \& terminology of steady state equilibrium;
short
term oscillations;
long-term stability;
systems approach;
holistic view;
open/closed systems;
storages;
flows;
balanced inputs \& outputs;
balanced processes (transfers \& transformations);
laws of thermodynamics;
tipping points;
stable equilibrium;
negative \& positive feedback;
ecosystem resilience;
sustainable development definition;
life-supporting services;
food webs;
population dynamics;
S curve;
carrying capacity;
cycles of matter;
flow of energy;
mean global temperature;
natural income;
natural capital;
MSY (maximum sustainable yield);
environmental/social/economic sustainability;
- breadth in addressing the concept of steady state equilibrium (SSE) as applied to a range of natural and/or anthropogenic systems and linking to how this concept contributes to understanding sustainability as the quest of human societies to achieve long-term stability (meeting the need of future generations), despite inevitable short-term fluctuations in the process of meeting present needs.
- examples of different steady state equilibria occurring in a range of natural \& anthropogenic systems, e.g. predator-prey cycles, fluctuation around carrying capacity, disturbance-prone ecosystems, nutrient cycling, timber harvesting, fisheries, crop/meat production, energy use, water extraction, etc. or unsustainable examples deviating from SSE;
e.g. deforestation, overfishing, global climate change, pollution, habitat loss, overconsumption etc..
- balanced analysis providing evidence supporting the idea that the concept of 'steady state equilibrium' is useful in understanding how various aspects of sustainability may be achieved in a range of systems. [Note to examiners: not how equilibrium is achieved in sustainable systems or how unsustainable systems deviate from equilibrium/balance. Still, such examples are implicitly linked to the context of the question].
- a conclusion that is consistent with, and supported by analysis and examples given e.g. Steady state equilibrium is inherent in the sustainable management and responsible use of natural capital. Short-term fluctuations are inevitable, as, for example, catching fish at a rate observing MSY, reduces temporarily the population, but soon it will regenerate through reproduction. Understanding that the important issue is to maintain the long-term stability of natural capital would help achieving sustainability of a system like wild fisheries.
Please see markbands on page 23.