1. POPULATIONS

2. A population . . .
consists of all the individuals of one species that live together in one place at one time.
A species can interbreed and produce VIABLE offspring.

3. Population Density:
The number of individuals of a species that live in a given area.

4. Carrying Capacity: Usually represented on graph as horizontal line:
The number in a population that an area can sustain.
Usually represented on graph as horizontal line:

5. Exponential Growth Curve:
Uncontrolled growth – leads to a crash.
Carrying Capacity
Population Size
Time

6. Exponential Growth Curve:
Uncontrolled growth – leads to a crash.
Carrying Capacity
Population Size
Time

7. Logistic Growth Curve:
Controlled population growth.
Population Size
Time
Carrying Capacity

8. A population . . .
may increase slowly or decrease as their size is limited by density-dependent factors.

9. Density-dependent factors:
Factors that limit the population due to the size of the population.
Examples: population stops growing due to predation, disease, starvation, competition

10. A population . . .
may increase slowly or decrease in response to density-independent factors.

11. Density-independent factors:
Factors that limit the population but have nothing to do with the population.
Examples: population stops growing due to flood, pollution, weather, climate

12. Adaptations:
Changes made in traits allowing a species to survive natural selection in changing environments
Examples: bird’s changing feather color to survive and attract mate, mouth parts changing to survive on different food items

13. Which graph shows overpopulation of a species no matter what factors are present?
time
Pop # A B
Pop #
time C
Pop # D
Pop #
time
time

14. D
Pop #
time
A decrease on a population growth curve shows the population overpopulated the area no matter what resources or limiting factors where there. The cause of the decline was overpopulation.

15. Which of the following contain “environmental factors”?
Organisms
Populations
Communities
Ecosystems

16. “Environmental factors” can be abiotic!
Ecosystems
“Environmental factors” can be abiotic!

17. Which of the following explains the graph below at point “A”, “B”, “C”?
time
Pop #
predator
prey C B A
When predator increases, prey decreases
When prey decreases, predators decrease
When predators decrease, prey increase

18. “A” When predator increases, prey decreases
“B” When prey decreases, predators decrease
“C” When predators decrease, prey increase
time
Pop #
predator
prey C B A