Chapter 3 Summary and Learning Objectives

Part B Summary

Part B reviews the natural systems that provide the life-support system for human existence on the planet as described in Chapter 1. Key concepts of natural science are discussed which include the scientific method, facts, theories, scientific law, and hypotheses. The importance of debate and disagreement in science is described, as well as the importance of both quantitative and qualitative data. Most of the concepts presented in this book are the result of the “scientific approach” to understanding different phenomena. There are other approaches, however, and one gaining increasing attention is traditional ecological knowledge (TEK). The scientific community now understands that Indigenous peoples often have detailed knowledge of their local environments. Scientists and Indigenous peoples are now realizing the benefits offered by the two systems of knowledge and management approaches and are trying to use both through co-management arrangements.

Chapter Summary

Energy ultimately comes from the radiant energy of the sun and is transformed into chemical energy in the form of food supplies before being converted to mechanical energy in the form of physical exertion and activity. In this chapter, you will gain an appreciation of energy in relation to such transformations, how energy flows through ecosystems, and the ecosystem consequences that result. The nature of energy is introduced and the laws of thermodynamics that govern its transformation. Energy flows in ecological systems are discussed in terms of producers and consumers, food chains, biotic pyramids, and productivity.

You also will be introduced to the main factors that control the structure and composition of ecological communities and how these interact to produce the biodiversity of our planet. This consists of abiotic components and biotic components which includes the influence of competition, biotic relationships, and keystone species. The three levels of biodiversity are discussed, with an emphasis on biodiversity in Canada. This chapter concludes with important implications for society and species distributions and what you can do to learn about your local ecosystems.

Learning Objectives

After reading this chapter, you should be able to do the following:

• Describe the nature of energy and state the laws governing its transformation
• Describe the way energy flows through the ecosphere and explain how it links ecosystem components
• Outline the main influences on the structure and nature of ecosystems
• Explain the nature and importance of biodiversity
• Describe the Canadian context for biodiversity and identify approaches and challenges with biodiversity conservation in Canada
• List and give examples of the ecological implications associated with the loss of biodiversity
• Discuss the importance of reducing energy use in society