TCORE 122D - Introduction to Science

Weekly In-Class Exercises & Discussions

Each week we will conduct these in-class exercises. Homework will primarily be to do the readings assigned and be prepared to participate in group discussions and contribute to the group's submission. With each exercise your group will prepare a single document as described in each below exercise. That document must contain the exercise number (week number), the date done and submitted, and all group members' names. Every group member will receive the same number of points for each

Week 1

Be prepared to discuss Meadows' Chapter 1. Page 12, a side bar comment re: a system being more than its parts. What is meant by the characteristics listed? Your group will discuss these and write a short explanation for what these characteristics mean and why they contribute to the claim of non-additivity.

Page 13: The “Think About This” box. Discuss and explain in a short essay each of the points in the box.

Model Answers

Since this exercise is not graded, but should help you orient to how to go about these exercises, here is a sample of what your answers should look like. Remember there are no such things as absolutely “right” answers, but there are usually several “good” and possibly many “bad” answers. Note the form below.

A System is More than Its Parts

The attributes given and interpretation:

  • adaptive - a system is able to modify itself with a range of possibilities when its environment changes. Example from the book: A tree can alter its water management based on water availability and temperature.
  • dynamic - a system is not static. Even a tree can grow limbs and leaves in response to sunlight availability. An animal generally moves about looking for food, etc.
  • self-preserving - many systems like animals move and adapt in order to keep themselves alive.
  • evolutionary - some kinds of systems are capable of not just adapting but actually changing their function or purpose over longer time scales (page 12).

Think About This (page 13)

Below are the main ideas. I asked you to write short paragraphs/essays to be a little more explicit. Those paragraphs should have tried to incorporate these ideas. Your answers may have been a little different and that is OK as long as you showed a rational and consistent interpretation.

A) refers to the complexity of the system.
B) concerns the fact that parts (components) making up a system interact with one another in particular ways.
C) concerns the idea that the system function (output) is different from any of the outputs of components taken alone - the system has to modify its inputs to produce its outputs and that takes the parts working together.
D) concerns the idea that the system function is basically the same over time and different environmental circumstances because it is capable of adaptation as needed to persist.

Week 2

Chapter 1 of Meadows' book starts looking at the modeling of systems using stocks and flows with controls over flow rates. In Chapter 2 she goes into details of how systems behave using feedback to self-regulate flows or levels of stocks. Read the first part of the chapter very carefully. In your groups discuss the sidebars on pages 39, 40, 45, 47, 48, 50, 54, and 57. Then answer the following questions in short essay format:

  1. From the principles of systems science slides which principles most apply to the sidebar considerations on page 39 and 40? Explain briefly.
    The side bar discusses the timing of feedback. This involves the principles of “dynamics” (#4), “regulation” (#8), and “information” (#7). Information feedback to a regulator (e.g. a decision maker) causes a system to respond or change its behavior, as when a thermostat detects that a noticable difference between the inside temperature and the desired temperature and turns on the furnace. The sidebar addresses the fact that there are inherent time delays in this reaction which is why we see the dynamics of a lag in response.
  2. Which systems science principle (or principles) applies to the sidebars on pages 47 & 48? Explain.
    Since the words dynamics and models are involved this would certainly involve #9 (models) and #4 (dynamics)! Using models allows one to ask what-if questions by changing some parameters in the model to see if it behaves differently, which might suggest the real system would also behave differently under those conditions.
  3. Which systems science principle (or principles) applies to the sidebars on pages 50, 54, & 57? Explain.
    As with the above these are all issues coverd by principles 4, 7, and 8.

    4. Follow Up: The point of this chapter is to introduce the basic ideas involving system dynamics (behavior over time) and feedback mechanisms for regulating that behavior. Information is an important aspect of feedback since it is the “force” that causes change in behavior. The key point about information feedback is the effects of time delays and especially the relations between different time delays in different loops. We were briefly introduced to the concept of complexity (in behavior) resulting from these different delays. In the next part of the chapter we will be looking at complexity in structures that lead to even greater complexity in behaviors. Then in the next several chapters we will bring in more of the principles and see how complexity increases in systems.

Week 3

We'll finish out Chapter 2 in Meadows and go into greater detail understanding system dynamics (which is largely the study of material and energy flows). The group should discuss the sidebar boxes in Meadows on pages 59, 63, & 71 based on each persons' reading of that chapter. Consider the meaning of exponential growth and limits to growth as described in the book.

In your group discussions try to answer the following questions in short essays.

  1. Can exponential growth of anything go on forever? If not, why? What limits growth?
    No. There are two possible reasons that a system stops growing or slows down. The first comes from internal constraints where the system includes internal regulations that prevent growth beyond a certain size. An example is the cessation of growth of a mature orgnaism once it reaches reproductive status. The second is from external limits imposed in the environment. Our economy's growth depends on increasing uses of energy. Right now over 80% of our energy comes from fossil fuels which are a finite resource. As we deplete that resource the ability to continue to grow diminishes.
  2. Which systems science principles apply to the concepts of energy flows, growth and limits, and capturing and storing energy?
    Principle 4 (Dynamics) will apply because the system does work with the energy flows - the work of constructing new internal organization needed for growth. In the above given example of energy from fossil fuels for the economy, increasing amounts of energy are required to build new capital (buildings, machines, etc.) and infrastructure (roads, railways) to support increasing economic work. Another example of limits imposed from outside the system would be the nutrients that plants need to grow. With agriculture the plants (crops) tend to deplete the soil nutrients which have to be replaced with fertilizers. If it were not for fertilizers farm production would slow down and eventually plants could not be grown in the soil. Principle 5 applies in that as systems grow they tend to grow in complexity as well.

We will explore the interrelations between several systems science principles and show how they relate to the systems thinking book. The biggest emphasis of the week will be on energy flows and capital (value) formation in growing and evolving systems.

Week 4

This week we begin to examine the nature of resilience and the use of feedback loops to manage an operation on several levels. Write answers to these three questions.

  1. From Meadows, chapter 3, what is meant by “meta-resilience”? How is it achieved? Can you think of any examples
    To understand meta-resilience you first need to understand what is meant by resilience in a system. Basically it is the existing ability of a system to recover from various kinds of disturbances (e.g. for a sailboat to regain its heading after being blown off-course). Meta means “a level above” so meta-resilience would be an ability to invoke some additional resources to repair a control loop that has been pushed past its limits (regular resilience). For example, if the tiller of the sailboat was broken, the crew might be able to rig a replacement so as to continue steering the boat. Another kind of meta-resilience would involve keeping spare parts on board in case something (like the tiller) breaks. Yet a higher level of meta-resilience would involve re-designing parts that break and replacing the old ones when in the shipyard. These last two involve learning and adapting.
  2. The sidebar on page 81: What is meant by the terms “learn”,“diversify”, and “complexify”?
    “Learn” means to have an ability to incorporate new knowledge into the system's knowldedge of the world and possibly of itself.
    “Diversify” means to use gained knowledge to change aspects of the system to take advantage of opportunities or avoid threats (as in the sailboat example above). To do new things that increase resilience.
    “Complexify” means that by increasing diversity the system must also increase its complexity in order to manage it. When there are more new processes from diversification it is necessary to add additonal coordination to make sure everything is cooperating.
  3. How does this apply to sustainable living? Can you think of an example of each of the terms in #2? What would resilience in a sustainable system look like in practical terms [HINT: think of things like droughts or floods]?
    In order to have a sustainable community the system has to not only have adequate sources for inputs, but also adequate internal capacities for resilience. For example if the community grows its own food it must have the ability to maintain stocks of non-perishables in case the growing seasons are not as good. It must be able to obtain extra supplies of water in the event of a drought season, etc. The community could learn from experience that there is higher variability in climate and then construct internal processes for dealing with that variability - they diversify their capabilities. But such diversification then requires that they add means for managing the increased capabilities. This leads to increased complexity.

Week 5

TBD

Week 6

TBD

Week 7

TBD

Week 8

TBD

Week 9

TBD