Unit D

Unit D Introduction

The howling of wolf packs was once heard over most of North America. These major predators of rabbits, mice, deer, elk, and bison helped to control the size of prey populations and maintain the integrity of the gene pool by removing the weak and the sick. Sadly, few wolf packs remain today. Scientists collect data to determine how interactions within and between populations contribute to these changes in wolf populations and how growth patterns differ between species.

In this final unit of Biology 30 you will examine three aspects of population and community dynamics. First, you will study populations, individuals, and gene pools. Based on your study of genetics, you will quantitatively study population changes that lead to natural selection by using the Hardy-Weinberg principle. You will learn the techniques used to count members of a population and ways to express this information quantitatively. You will examine the methods that biologists use to determine how populations change over time and analyze the implications. You will be introduced to the gene pool and learn how to quantify its makeup, determine whether it is changing, and analyze the factors that lead to this change. You will investigate how many factors can interact to cause populations to evolve or remain stable.

Next, you will examine ecological interactions by studying how organisms interact with each other and with members of other populations in their many roles in ecological communities. Through these interactions and symbiotic relationships, you will discover the mechanisms of defence in a competitive world where the goal is to live long enough to reproduce and contribute survival characteristics to the gene pool. In a broader application, you will study how the makeup of communities changes over time in the process of succession.

Finally, you will explore the measurement, interpretation, and analysis of changes in populations. You will examine various population growth models that have been developed by biologists to describe how changes to population size can be measured and interpreted, and you will see how the results of these studies can be applied to the control of population growth. You will discover the many ways a population adapts to change and maintains equilibrium. You will analyze the growth of the human species as an example of a population in a community whose growth is problematic and significantly affects the growth patterns of other species sharing the planet. You will understand how an individual’s contributions to the gene pool and the interactions within communities may result in change over time because of natural or artificial events.

In Biology 20 you learned a great deal about equilibrium and maintaining balance. In Unit A you learned about equilibrium in the biosphere, how equilibrium is achieved, and the human impact on this balance. In Unit B you learned about the biotic and abiotic components of ecosystems that compose the biosphere. You also studied the mechanisms involved as populations change over time. In this unit you will build upon those understandings.

Specifically, you will learn to

• explain how populations can change over time
• describe the ways that members of a population can interact with each other and with members of other populations
• analyze quantitatively how populations change over time
• analyze the technologies used by society to control and manage populations

As you work through this unit, you may go to the McGraw-Hill Ryerson online learning centre at www.albertabiology.ca. Click on “Student Resources” in the column on the left side of the screen. Click on the “continue” button. You should now be on the main Inquiry into Biology page. Listed on the left side of the screen are the many resources that are available to you. Click on “Essential Study Partner” in the left column. Then, click on the “Essential Study Partner” in the white part of the screen. Next, click on the “evolution” icon or the “ecology” icon. Here you will find many resources to help you with your study of this unit.

As you work through Module 8, there will be self-checks, labs, lesson assignments, module assessments, and a unit assessment. Assessment items will be clearly identified for submission to your teacher. All course work should be stored in your course folder.

Unit D comprises 15% of the Biology 30 course and should take approximately 19 hours to complete.

Before you begin the unit assessment, you may wish to do the “Review” questions on pages 744 to 747 in your textbook. You may wish to consult with your teacher about which of these questions it would be appropriate for you to answer. Review your responses with your teacher.

When you have finished Unit D and are ready to begin the unit assessment, go to the Unit D Assessment section of the course for instructions.

Unit D assessment follows the Diploma Exam format. The assessment will involve thirty multiple-choice questions and a written-response question. The written-response question will involve applying your knowledge to some of the wildlife management issues faced by the National Parks. Remember from the Biology 30 Course Introduction that multiple-choice questions are introduced with background information that you will need to read carefully in order to answer the questions successfully. Many of the questions in this unit involve calculations and other examples of quantitative analysis. Make sure that you have a calculator. You may wish to read “Tips for Success with Assignments” in the Biology 30 Course Introduction.