1. Chapter 5 Populations 5-1 How Populations Grow page 119
Review Worksheet 5-1

2. Bell Work
Review the two graphs in figure 5-3 on page 121 How are the graphs alike? How are the graphs different?

3. Bell Work Review
Same- Both plot time on the Horizontal axis and the number of organisms on the Vertical axis. Both are J shaped
Different- The size of the population hundreds of thousands vs. millions and time hours vs. years
What do these differences indicate? Bacteria reproduce very rapidly in a short period of time while elephants reproduce much more slowly over a long period of time.

4. 5-1 Key Concepts
What characteristics are used to describe a population?
What factors affect population size?
What are exponential growth and logistic growth?

5. Characteristics of Populations
Several terms can be used to describe a population in nature: The four main terms, or characteristics, of a population are a. geographic distribution b. density c. growth rate d. age-structure

6. Characteristics of Populations
What is a population’s Geographic Distribution?
Geographic
Distribution
describes the area
inhabited by a
population.
Another term
Is Range

7. Characteristics of Populations
What is population density?
It is the number of individuals per unit area
Population Density = Number of Individuals
Unit Area

8. Characteristics of Population Population Density

9. Population Growth Populations can grow rapidly
Populations can decrease in size
Populations may stay the same from year to year

10. Population Growth
What are the three factors that can affect population growth?
Number of births
Number of deaths
Number of individuals that enter or leave the population

11. Population Growth
If more individuals are born than die in any period of time, how will the population change?
Population
will grow

12. Changes in Population Immigration – Population movement into an area
Results in population growth
They may immigrate to find a mate or find food

13. Changes in Population Emigration
Movement of a Population Out of an Area
EXIT
Results in Population Decrease

14. Exponential Growth
How will a population change if there is abundant space and food and if the population is protected from predators and disease?
The organisms will multiply and the population size will increase

15. Exponential Growth When does exponential growth occur?
When the individuals in a population reproduce at a constant rate
Under ideal conditions
Absence of Predation or Disease

16. Exponential Growth
What are three ways that a growth rate may be stated, or expressed?
It may be stated as doubling time, a birthrate per female, or a percentage of growth per year.

17. Exponential Growth

18. Logistic Growth Exponential Growth
Does not continue in natural populations for very long
When resources become less available, how does population growth change?
It slows or stops

19. Logistic Growth When does logistic growth occur?
When a populations growth slows or stops following a period of exponential growth
A populations growth will slow down when:
the birthrate and death rate are the same
the rate of immigration and emigrate are equal

20. Logistic Growth A populations growth will slow down when
The birth rate is ______________
down
The death rate is ______________ up
When immigration is ____________
When emigration is ______________

21. Carrying Capacity
What is the carrying capacity of the environment for a particular species?
It is the largest number of individuals that the given environment can support.

22. Population Growth
J shape vs. S shape

23. Carrying Capacity Overshoot –
What is the carrying capacity for this population?

24. Exit Ticket
What factors might cause the carrying capacity of a population to change?