Constructing Their Own Understanding

Objectives:

The Student will be able to

1. understand systems and how they work
2. understand the difference between open and closed systems
3. use Barry Commoner's four laws of ecology to help them understand how human interaction with the environment both helps and hurts our ecosystem
4. be aware of the ways in which their actions impact our planet

Key Terms:

system
closed system
open system
interdependence
ecosystem
ecology
interaction
acid rain
greenhouse effect
biodegradable

Materials:

Experiment: What Is A System?

Reading: Everything Is Connectd To Everything Else

A working flashlight that can be taken apart to reveal its components, including batteries, casing, bulb, reflector, etc.

Teaching Sequence:

In preparation for the lesson, students have been asked to bring pictures from magazines and newspapers of anything, animate or inanimate, that is made up of parts that work together.

With you flashlight ready, have a student begin to read What Is A System? aloud in class. At the end of the second paragraph, interrupt the reading to show your students the first example of a system--your flashlight. Remove one part of the flashlight at a time, leaving the other parts as intact as possible so that students can see how the parts of the flashlight are related to one another. After you have taken the flashlight apart, you may want to have students try to put the parts into different positions in the flashlight system to see if it works. Ask students why they think a flashlight is a system. They should see that the entire flashlight system, like any other system, is affected when one or more parts is removed or exchanged.

Now have a student continue to read the experiment up to the end of the fifth paragraph aloud. Take time to examine the Rube Goldberg system in the cartoon with the class, emphasizing the interdependence of its connected parts.

Finish reading the experiment, discussing the role of humans in the Earth system. Encourage students to ask questions about the nature of open and closed systems. Then ask students to share the illustrations of systems that they brought with them to class. Have the class decide if each illustration is an example of an open system or a closed system.

Students should summarize this lesson in their spiral notebook. Their summary should include definitions and examples of systems, open systems, and closed systems. At this point in the lesson you may want to have students do activity 1.

Have students read Everything Is Connected To Everything Else. Students should use the PQRST or SQ4R method of reading/studying for this assignment as they should with all textual reading. In the first two steps of these reading/study methods students preview or survey the reading material, looking closely for text structure and any prior knowledge. Students also make inferences as to what the reading is about. In step 4 Summarize, students are asked to organize the reading into their own notes. Students who have difficulty outlining or taking notes may use the review questions as guides. Answers to the review questions should be reflected in their notes. Review the reading with students to be sure everyone understands the four ecology laws. Students should offer examples of the laws as part of the discussion.

Everything is connected to everything else.

Everything must go somewhere

Nature knows best

There is not such thing as a free lunch

The following assignments are examples of ways students may achieve the objectives for the lesson. These activities not only combine reading and writing, but also speaking, research and cooperation among students. Any of these activities may be done by a single student or a group of two or more. While any of the activities may be sued as evaluation the critical thinking essay was designed for this purpose. Students essays should show an understanding of systems and how they work, both open and closed and an understanding of the four ecology laws. (See Objectives)

Activity 1:

Have students think of a system with which they are familiar and illustrate how it works. The system may be either a closed or an open system. Here are some examples of systems"

A team (football, basketball, baseball)

Your family

A camera

A factory or business

Your school

Those are just a few systems. There are many others.

They may choose to create their own original system, as Rube Goldberg did. In any case, they should bring a drawing or model of their system to class. They should be prepared to explain how it works. They should also be ready to explain what happens to their system when one or more of its parts are changed or removed. They should show how all the parts of their system are interdependent.

Activity 2:

Divide the students into four groups. Assign one of Barry Commoner's laws of ecology to each group. Then ask each group to decide on a way to illustrate its law of ecology to the rest of the class. For example, one group may choose to write and perform songs or a skit. Another group may want to draw or paint posters or murals. A third group could present a television news show with several reports illustrating its law of ecology. Point out that more than one group can choose the same format.

Once the groups have decided on their formats, they must figure out how to present their particular laws. Encourage each group to identify problems or situations that will illustrate its law. For example, for the third law ("Everything must go somewhere.") students could focus on an immediate problem such as litter in their neighborhood, or on a more global problem such as the disposal of nuclear or toxic waste. This group could also focus on both aspects by showing how problems in the immediate environment are connected to global problems. When the presentations are complete, have the groups share them with the rest of the class.

Activity 3:

Have the students choose at least two different environmental issues, such as global warming, the destruction of the rain forests, endangered species, oil spills, and waste disposal, and collect three to four current newspaper or magazine articles about each of them. For each issue, ask students to write a short essay describing how they and their families are contributing to the problem, and how they could change their behavior to have a more positive impact on our planet.

Evaluation: Critical Thinking Essay

Suppose that their was a controversy about a proposed dam. The dam would provide electricity at low rates in a poverty-stricken area. The dam would encourage the development of new jobs for the people of the region. However, the dam would destroy the only breeding ground of a rare lizard and the only place in the world where several kinds of rare mosses grow. What argument would an ecologist such as Dr. Barry Commoner give against the dam?

This Geography Lesson was written by Dorothy L. Lewis.