Module 9S1 Ecological Interactions

Lesson 4.9.3S1

Lesson 3—Populations and Communities Changing Over Time

Get Focused

You may be surprised to find that a small grassy meadow surrounded by forest that you enjoyed when you were a child had disappeared 5 years later. What you would see in the place of grasses (at least in Central Alberta) would be wild roses and thistles. A few years later, wild rose and thistle would begin to be replaced by wild raspberry bushes, Saskatoon berry bushes, hazelnut bushes, high-bush cranberry, and dogwood shrubs. Several years later you could have returned to the same place and found some chokecherry and pincherry trees nestled amongst a forest of mature aspen trees. If you continued to return year after year, you would find that the aspen forest remained.

In the same way that individuals go through life cycles from young to old, communities age as well, with one species succeeding another. This species changes the environment enough that it can no longer live there, making the environment suitable for a more adapted new occupant.

At the end of this lesson you should be able to answer the following focusing question:

• How do communities and their populations change or remain stable over time?

Module 9: Section 1—Lesson 3 Assignment

Once you have completed all of the learning activities for this lesson, you can complete the online assignment.

Bio30 4.9.1S1 online assignment

You should also watch the tutorial video for this lesson and submit a summary.  Bio30 tut# 4.9.3S1 Succession

In addition to your lesson work as listed below, any 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.