1. How do communities change over time?
Population Growth
How do communities change over time?

2. Say Something… Groups of 2, 3, or 4…spread out…face each other!
Chunk/Divide up the text.
Decide how to read (Independently? Aloud? Take turns?)
Begin. When it’s your turn to “say something” do one of the flowing using the discussion stems provide:
Make a prediction
Ask a question
Clarify something you misunderstood
Make a comment
Make a connection
Say Something…

3. Population growth
called
EXPONENTIAL GROWTH
Populations will grow until they reach their biotic potential, unless they are limited by factors in the environment
This type of growth is known as a J-curve

4. Exponential Growth (J-curve)
As a population gets larger it also grows faster.
Resources (food, water, space) are unlimited and plentiful.

5. Population growth
called
LOGISTIC GROWTH
As resources (called limiting factors) become scares, the population growth will slow.
This type of growth is known as a S-curve.

6. Logistic Growth (S-curve)
Population growth eventually slows/stops and stabilizes when it reaches its carrying capacity
Resources (food, water, space) are scarce and in limited supply.

7. Logistic Growth
Occurs when a population’s growth slows or stops following a period of exponential growth
As resources become less available, the growth of a population slows or stops

8. Population growth
Carrying capacity is defined as the number of individuals an environment can support.

9. Population growth
Limiting factors in the environment help to maintain ecosystem stability by allowing populations to fluctuate around the carrying capacity.
This is called dynamic equilibrium.

10. What is the CARRYING CAPACITY of the deer on WallaWalla Island?

11. LIMITING FACTORS
A limiting factor is a factor that causes population growth to decrease.
2 TYPES:
Density-Independent
Density-Dependent

12. DENSITY – DEPENDENT LIMITING FACTORS
DDLFs are resources that have greater effects as the population size/density increases.
 Affects larger population sizes/densities

13. EXAMPLES of DENSITY – DEPENDENT LIMITING FACTORS
Availability of Food
Availability of Water
Availability of Space
Competition
Disease
Predation
Migration

14. DENSITY – INDEPENDENT LIMITING FACTORS
Resources/factors that affect all populations, regardless of the population density (size).

15. DENSITY – INDEPENDENT LIMITING FACTORS
Resources/factors that affect all populations, regardless of the population density (size).
Affects all population sizes/densities.

16. EXAMPLES of DENSITY – INDEPENDENT LIMITING FACTORS
Natural Disasters (floods, hurricanes, earthquakes, tornadoes, forest fires, etc.)
War and Human Activities
Weather (drought)
Temperature (frost)

17. Practice! Complete the practice worksheet (both sides).
Finish for Homework