Lewis/Life - Teaching Techniques

Chapter 43 - Teaching Techniques

A. General Tips
Chapters 41 - 44 deal with problems for which there are no simple solutions. Your students, however, will be looking for simple solutions. Be on guard for simplistic approaches to complex situations. Play devil's advocate liberally throughout this material.
Chapter 43 reads easily and the points included are easy to understand. Personally I believe that a study of the biomes is essential to our understanding of biology today. Nevertheless, if you are having time problems, this chapter could be completed quite successfully outside of the lecture hall.
Lewis mentions on page 872 that the discussion is limited to representative biomes. This is an important point. Biomes can be divided and subdivided. Not everyone agrees on the names of the biomes; not everyone agrees on the defining factors in the biomes. Your students may have had a unit on biomes that was put together in a very different way. The names are not nearly as important as are the overriding concepts. Equally important is the fact that global trends in communities and ecosystems can be identified. All biomes are a superb mesh of life forms, geology, climate, and as yet undefined interactive variables. Give your students an appreciation of the vastness of this part of biology.
You might wish to copy and distribute to your students the Overview of Chapter Objectives flowchart found at the beginning of this Instructor's Manual Chapter.
B. Possible Approaches to the Chapter
I suggest that you construct a chart for this chapter. Start the chart in class but assign it for completion outside of class time.
Here is one possible way of constructing your chart:
Group the eleven biomes covered in this chapter and put them down the side of the chart. Across the top list temperature, precipitation, vegetation, animal life, and cycles. (Include a column for other factors, if that seems appropriate.) Fill in the boxes accordingly. Under cycles include both nutrient cycles and chemical cycles. These cycles are often the forgotten part of the biome chart.
Throughout this chapter, try to instill in your students an awareness of the vastness of the biomes and of the tremendous variety of complex organisms and environments found in each of these divisions of our planet.
Use a world map. If your lecture hall has a pull-down map, use it. Otherwise, use a map on the overhead projector or require that the students bring their books to class on the days you are discussing biomes. It is important that they gain a global sense.
There are many anecdotes in this chapter. These anecdotes can be used to add breadth to your coverage or to add depth to individual points. The anecdotes can also be used to encourage outside research. You can certainly assign specific points to be covered either for outside assignments or for extra credit.
C. Hints Related to Specific Chapter Topics
- I. Stress that these biomes comprise one group of biomes. The Overview of Chapter Objectives flowchart is essentially a delineation of the biomes.
- I.A. You might want to spend a little time with the concept of vertical stratification. Students very often have only the vaguest idea of what any forest is like -- let alone a rain forest. They need to be able to visualize the layers of the canopy and understand the strategies plants use to compete for sunlight. Stress the nutrient cycling.
- I.B & C. Use the decomposers of the temperate forest as your vehicle to discuss not only nutrient cycling but also energy cycling.
- I.D. Stress the intricate anatomy of the conifer leaves (needles). Refer back to the conservation of water mentioned in the plant unit.
- I.E. It is interesting to challenge the students to explain the similarities and differences between the savannas and the grasslands.
- I.F. One of the biggest misconceptions students have is that the tundra is lifeless. Challenge them to identify the strategies different plants and animal have developed to survive in the tundra.
- I.G. The Arctic regions are often classified as deserts because of the minimal precipitation these areas receive. Ask the students what should be done with classifying the Arctic.
- II.A. Use Figure 43.9 to teach this section. Let the students absorb the intricacies of this ecosystem. Quite a few terms are used. Which one will you expect your students to be responsible for?
- III.B. Use Figure 43.12 to teach this section. Again, let the students absorb the intricacies of this ecosystem. Know in advance which terms you will expect them to remember.
- IV. An El Niño began in the summer of 1997. What effects did it have on the ecosystems?