ACOS#16.) IDENTIFY DENSITY-DEPENDENT AND DENSITY-INDEPENDENT LIMITING FACTORS THAT AFFECT POPULATIONS IN AN ECOSYSTEM.

Populations5-2 Limits to Growth

Section 2- Take 5Pickin’ Prior Knowledge

Take out a sheet of paper

On your paper distinguish between immigration and emigration (We talked about these two in section 1)

Give me a rough definition or example of each!

You may NOT use your book or your friend This is to see if you know the difference

This will be turned in to Ms. Clayton

Video clip on Limiting Factors

First, we are going to watch this quick video on limiting factors! Pay attention

http://www.youtube.com/watch?v=CuwrZUTeEqM

Limiting Factors

Definition- A factor that causes population growth to

DECREASE

Examples can be seen on page 124 in figure 5-5

A resource base that is limited can also affect the long-term survival of a species

Examples?

Density-Dependent Factors

A limiting factor that depends on population size is called a density-dependent limiting factor.

In general, density-dependent factors are biological factors

Some examples of this include competition, predation, parasitism, and also disease

Density- Independent Factors

Definition- This is when all populations are affected in similar ways, regardless of the population size.

Examples? Unusual weather, natural disasters, seasonal

cycles, and certain human activities—such as damming rivers and clear cutting forests

Activity- Application

Get in groups on 3 or 4 for this activity

Read the passage “Yellow Perch in Lake Winnepig” aloud (each student should follow along throughout the passage)

Answer the questions that follow in your group on your OWN SHEET OF PAPER (everyone must have their own sheet to turn in)

Activity Questions 1 & 2

1) Explain the difference between density independent and density dependent limiting factors.

2) From the previous article “Yellow Perch in Lake Winnipeg”, identify and describe as many limiting factors as possible and classify them as density independent or density dependent.

Density DependentDensity Independent

Activity Question 3

3) Each of the statements below involves a situation that will affect the growth of a population.

Classify each of the statements as DD (density dependent) or DI (density independent) and give a reason for your choice. (18 marks - 2 each)

a. Rainbow smelt and yellow perch attempt to occupy the same area. The more aggressive

smelt survive; the perch do not. b. A severe flood brings a lot of sediment and silt into

Lake Winnipeg. The turbidity of the lake increases greatly.

c. A drought decreases the water level in Lake Winnipeg. The carrying capacity of the lake

decreases.

Activity Question 3

d. Due to the introduction of rainbow smelt, Lake Winnipeg becomes crowded and some fish species do not survive.

e. Since northern pike prey on yellow perch, an increase in the perch population causes an increase in the pike population.

f. Many fish die due to an increase in water temperature.

g. Due to over-fishing, the number of walleye in Lake Winnipeg decreases.

h. A population is growing quickly when parasites cause disease to spread quickly.

i. Since lake sturgeon migrate long distances to spawn, many do not survive the trip.

Exit Slip-Preparation for Thursday’s lesson

On your note card given to you by Ms. Clayton-

Question-Think about how the size of the human

population has changed over time and explain to me why population growth rates differ from country to country.

This should be 2-3 sentences in length and have your name on the opposite side as your answer