Module 8
1. Module 8
1.31. Lesson 8
Module 8—Populations, Individuals, and Gene Pools
Lesson 8—Factors Influencing Growth
Get Focused
Elk Island Bison
© thepoeticimage/43322/ Fotolia
The bison, which once dominated the plains of Alberta, represent a species that is perfectly adapted to its environment. However, when European settlers discovered that bison hides made beautiful coats and robes, and that there was a huge market for these products in Europe, the bison were hunted until its population size bordered on extinction. To protect the remaining bison from hunters, excessive predation, and disease, reserves such as Elk Island National Park in central Alberta were created as safe havens.
In open populations, individuals are free to roam—they may immigrate or emigrate. What happens when natural populations are enclosed with fences for their own protection so that immigration and emigration are not possible?
While it is true that enclosing the bison allows wildlife managers to monitor the birth and death rates, keep the number of predators at a reasonable level, and monitor for the presence of disease, it also creates problems. In natural populations, individuals come and go, bringing with them “fresh” alleles that keep variation in the population high, prevent inbreeding and genetic drift, and ensure enough variation to protect the population from extinction in the event of environmental change. The wildlife managers of enclosed game parks and conservation reserves have the difficult job of balancing the benefits of maintaining a large population size with the risks of losing genetic diversity.
In this lesson the following focusing questions will be examined:
- What are the factors that influence population size?
- How do these factors influence population change?
Module 8: Lesson 8 Assignment
Download a copy of the Module 8: Lesson 8 Assignment to your computer now. You will receive further instructions on how to complete this assignment later in the lesson.
Summary notes, diagrams, charts, or tables should be stored in the course folder for your teacher’s feedback and study as you prepare for exams.
The other questions in this lesson are not marked by the teacher; however, you should still answer these questions. The “Self-Check” and “Try This” questions are placed in this lesson to help you review important information and build key concepts that may be applied in future lessons.
After a discussion with your teacher, you must decide what to do with the questions that are not part of your assignment. For example, you may decide to submit to your teacher the responses to “Try This” questions that are not marked. You should record the answers to all of the questions in this lesson and place those answers in your course folder.
Remember, you also have the option of trying additional questions from the textbook for further practice. Consult with your teacher for the answers to these questions. The Key will also provide you with many Diploma Exam-style multiple-choice, numeric-response, and written-response questions that will be an excellent review of the module. Practising your responses to these types of questions is good preparation for the Diploma Exam.