1. Ecosystems Limiting Factors SC.912.L.17.5 ESSENTIAL QUESTION:
How do abiotic (physical) limiting factors affect growth and survival in an ecosystem ?

2. Let’s suppose…. We have two mice…:
and they produce the standard 56 “pups” (baby mice) each year.
and each of these mice goes on to have 56 babies each year….

3. Soon….. We’d be over-run with mice on the planet!!
Why doesn’t this occur?

4. Limiting Factors
A limiting factor is an abiotic or biotic factor that restricts the number of individuals in a population.

5. ARTICLE: Limiting Factors
JIGSAW
ACTIVITY
Read your assigned section as a group.
Share what you learned about limiting factors with the class

6. VOCABULARY Term Definition Visual limiting factor population ecosystem
predator
prey
habitat
species
carrying capacity
resource
degradation
reproduction

7. Limiting Factors
Limiting factors can include:
Competitors

8. Limiting Factors Limiting factors can include: Competitors
Disease and parasites

9. Limiting Factors Limiting factors can include: Competitors
Disease and parasites
Weather

10. Limiting Factors Limiting factors can include: Competitors
Disease and parasites
Weather
Fires

11. Limiting Factors Limiting factors can include: Competitors
Disease and parasites
Weather
Fires
Available habitat

12. Limiting Factors Limiting factors can include: Competitors
Disease and parasites
Weather
Fires
Available habitat
Predators

13. Competitors-organisms both cooperate and compete
Birds of prey
Live in forests on the edge of fields
Eat mice and other rodents
Nest in trees
Red-Tailed Hawk
Barred Owl

14. Diseases and parasites can be dependent on population size and habitat
Disease and Parasites
Diseases and parasites can be dependent on population size and habitat

15. Weather
Storms
Drought
Flooding
Heat/cold

16. Fires
Fires lead to succession which is a predictable change in the community over time.

17. Available Habitat Human activities play a large role
Development, damming rivers, clear cutting forests.

18. HOT LAB: Limiting Factors
Problem Statement:
Part A: How will resource availability affect the population of a species in an ecosystem?
Independent Variable:_________________
Dependent Variable: __________________
Hypothesis: If ________ then ______.
Part A:

19. DATA: Effects of Resources on Deer Population
Year (round)
Deer Population (#)
# Resources 7 
21  1
14 
 14 2 20  8 3
18 
11  4
 22  7 5
 13
 16 6
 28  1 7  2
27 

20. HOT LAB: Limiting Factors
Problem Statement:
Part B: How will a density-independent limiting factor (flood or drought) affects the population of species in an ecosystem?
Independent Variable:_________________
Dependent Variable: __________________
Hypothesis: If ________ then ______.
Part B:

21. DATA: Effects of Natural Disturbances on Deer Population
Year (round)
Deer Population (#)
Resources (#)
Events 7 
21  1
 14
14  2
 24 5 3
 12
17 
Flood 4
15 
 28 1  6  2
27  7  4 25 8  8
 21
drought 9
 25

22. HOT LAB: Limiting Factors
Problem Statement:
Part C: How will a density-dependent limiting factor (predator) affect the population of species in an ecosystem?
Hypothesis: If ________ then ______.
Part C:

23. DATA: Predation Year (round) Deer Population (#) Predator (#) 7 1 1 87  1  1  8 4  2  6 6  3  1 4  2 5 6 7

24. ANALYSIS QUESTIONS List the basic needs of animals.
Describe the relationship between resource availability and population growth or decline.
Describe reasons for the fluctuation of the population.
Define “limiting factors” and provide three examples.
What is the carrying capacity for the deer population according to your graph?
Once the deer population goes significantly above carrying capacity, describe what happens to the deer population in the years following.
How did the introduction of a predator affect the deer population in terms of population size and deer behavior?
What was the peak population for the deer population when there were no predators? What happened after the peak? Why?
How might this “simulation” differ from the real relationship between deer and their environment? Write at least two differences and explain.
How do you think this “simulation” game differs from real predator-prey relationships? Explain.

25. Predators
Predator-prey relationship can be a delicate balance between the two populations.

26. Predators
As the prey population increases, the predator population increases. As the prey population decreases, then so does the predator population.

27. Example: Lynx and Hare:

28. VIDEO: How the wolves changed the river?