1.2 Systems

Guiding question

How can the systems approach be used to model environmental issues at different levels of complexity and scale?

Click here for a Quizlet vocabulary set for ESS topic 1.2 Systems.

SL and HL knowledge statements

1.2.1 Systems are sets of interacting or interdependent components.

1.2.2 A systems approach is a holistic way of visualizing a complex set of interactions, and it can be applied to ecological or societal situations.

Using systems theory to study ecology

1.2.3 In system diagrams, storages are usually represented as rectangular boxes and flows as arrows, with the direction of each arrow indicating the direction of each flow.

1.2.4 Flows are processes that may be either transfers or transformations.

Why Aren’t Energy Flows Diagrams Used More To Inform Decarbonization? – CleanTechnica

1.2.5 Systems can be open or closed.

Biosphere 2 is an example of a closed system

1.2.6 The Earth is a single integrated system encompassing the biosphere, the hydrosphere, the cryosphere, the geosphere, the atmosphere and the anthroposphere.

James Lovelock explains the Gaia hypothesis

What is the anthroposphere? by the Aspen Global Change Institute

1.2.7 The concept of a system can be applied at a range of scales.

1.2.8 Negative feedback loops occur when the output of a process inhibits or reverses the operation of the same process in such a way as to reduce change. They are stabilizing as they counteract deviation.

Here’s a clear explanation of the Daisyworld model developed by James Lovelock and Andrew Watson

This NetLogo Daisyworld simulator lets you change the parameters of Daisyworld world to see how it changes the feedback mechanisms.

1.2.9 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 will be maintained by stabilizing negative feedback loops.

Most ecosystems rely on interdependent negative feedback loops to maintain a steady-state equilibrium

1.2.10 Positive feedback loops occur when a disturbance leads to an amplification of that disturbance, destabilizing the system and driving it away from its equilibrium.

Arctic amplification is a classic example of positive feedback destabilizing Earth’s climate system

1.2.11 Positive feedback loops will tend to drive the system towards a tipping point.

1.2.12 Tipping points can exist within a system where a small alteration in one component can produce large overall changes, resulting in a shift in equilibrium.

Grist has a great summary of 7 climate tipping points called Points of No Return. Check it out for a detailed look at Earth’s possible future.

1.2.13 A model is a simplified representation of reality; it can be used to understand how a system works and to predict how it will respond to change.

1.2.14 Simplification of a model involves approximation and, therefore, loss of accuracy.

1.2.15 Interactions between components in systems can generate emergent properties.

1.2.16 The resilience of a system, ecological or social, refers to its tendency to avoid tipping points and maintain stability.

While this video is primarily about the economic benefits of biodiversity conservation, the part that explains why diverse forest grow more rapidly than less diverse ones is a great example of systems – the inputs and outputs of the different forests are different.

1.2.17 Diversity and the size of storages within systems can contribute to their resilience and affect their speed of response to change (time lags).

1.2.18 Humans can affect the resilience of systems through reducing these storages and diversity.

Practical activities

Create and use diagrams representing examples of negative feedback.

Possible engagement opportunities

Build a bottle ecosystem, aquarium, terrarium, compost heap or other school-based ecosystem and use it to construct a systems diagram. Compare variables of the system (for example, with and without one organism or with different levels of water/nutrients).
Use the skills of system analysis to help solve a school-wide problem.
Advocate to peers to educate them about the importance of tipping points.

Happy learning!