Lesson 2 Factors Limiting Population Growth

Below are several videos to help you with this assignment.  All living things need food, water, shelter and space to survive.  As long as organisms have all of these things available to them their population will continue to grow.  However, populations can not grow forever.  Some form of environmental resistance will stop the population's growth.  The form of environmental resistance is called a limiting factor since it limits the population.  We will look at many different limiting factors and classify them into abiotic and biotic factors.

Objective:  Students will understand factors limiting the growth of populations. Students will apply their knowledge to a real life example.


Click here to download smartboard presentation.  Also refer to textbook pages 98 - 103. 

Assignment:  Answer the following questions using your sheet of paper.

1.  Abiotic factors affect a population no matter what it's size is.  For example, natural disasters.  List at least five abiotic factors that can limit a population size.  Generally speaking, how can abiotic factors limit a community's species richness?

2.  Biotic factors can only affect a population when the population reaches a large size.  There are three main biological limiting factors controlling population size.  List the three main biotic limiting factors when a population gets too large.  Explain how they keep a population size under control.  Why is it necessary to keep population sizes in check?

Use the following graph to answer the next set of questions.

population size graph

3.  On your sheet of paper, turn this bar graph into a line graph.  You do not have to use numbers; just sketch it's general shape.  Now, label the growth phase, stationary phase and death phase.

4.  List factors that could be leading to a growth phase.

5.  List factors that could be leading to a death phase. 

6.  Predict what will happen to this population several years after the death phase and support (list reasons) your choice.

7.  Now, let's apply our knowledge to a situation currently affecting Alberta grasslands.  Click here to download the Thought Lab Worksheet.  Complete the worksheet.  Remember to use terms that you have just learned in class to this situation.