1. How did we get so big so fast??
What information do scientists need to know to project the size of the human population?

2. Population Dynamics
Variables

3. Po (pronounced P naught)
The starting population
Changes depending on which generation you are calculating. (ex. If you are calculating the population of the 5th generation, your Po would be the population size of the 4th generation.

4. Pn
The population of the generation you are looking for. (Ex. If you are calculating the population size of the 5th generation, you would be looking for P5

5. b
Birth rate
A percent of the population that will give birth. (When calculating remember to change your percents to decimals).

6. d
Death Rate
A percent of the population that will die. (When calculating, remember to change your percents to decimals).

7. Inquiry
This is the fun part! This is where you get to exercise that brain and use what you know to come up with an answer! *There is more than one right answer!
Remember…What things did we say we needed to calculate future populations?
P0 b d

8. Group Compare/Share
Time to compare and share your group’s equation with another table.
How are they similar?
How are they different?
Is there one you like better?

9. Class Compare/Share
Hold your white boards up so I can share your equation on the Elmo.

10. r Is a variable ecologists use to represent growth rate.
r= (birth rate) – (death rate)

11. r (Now add this to your variable list on page 1.)
Growth rate
how quickly the population is increasing OR decreasing in size.

12. Pn= Po + rPo
This is the equation we will use in class to calculate population growth.

13. Compare my equation with yours!
Make any necessary changes to your equation.

14. Plickers Questions!

15. 1. What does the variable r represent?
A. rate of time
B. rate of growth
C. rate of births
D. rate of deaths

16. The variable that represents the starting population is represented by:
A. Px C. Po
B. Pi D. Pn

17. Now use the equation to calculate the population for each of the 15 generations for the kelp population on the back of the page, then GRAPH it!
**HINT: Round your population sizes to the nearest whole number.

18. Discussion Question Exponential
How would you describe the pattern(s) of growth in your group’s graph? (Use words like stable, increasing/decreasing, quickly/slowly.)
Based on the growth curve you see, what type of growth is occurring?
Exponential

19. Discussion Questions

20. Density Dependent
Any factor that can limit the size of a population as the population size/density increases
For example, disease will have a greater effect in limiting the growth of a large population, since overcrowding facilitates its spread.

21. Density Independent
Any factor that can limit the size of a population regardless of the size/density of the population.
An example of such a factor is an earthquake, which will kill all members of the population regardless of whether the population is small or large.

22. Exit Card
Write down three factors you think can slow down exponential growth and DROP IT IN THE BASKET ON YOUR WAY OUT!
If it’s density Dependent write a “D” next to it.
If it’s density Independent write an “I” next to it.

23. Plickers questions!

24. When graphed, exponential growth is best represented by what letter(shape)?
A. M C. S
B. J D. V

25. Which type of growth has been affected by the ecosystem’s carrying capacity?
A. Exponential
B. Decreasing
C. Logistic
D. Increasing