Limiting Factors

EcosystemsSC.912.L.17.5

ESSENTIAL QUESTION:How do abiotic (physical) limiting factors affect growth and survival in an ecosystem ?

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….

Soon…..

We’d be over-run with mice on the planet!!

Why doesn’t this occur?

Limiting Factors

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

ARTICLE: Limiting Factors

Read your assigned section as a group.

Share what you learned about limiting factors with the class

JIGSAW

ACTIVITY

Term Definition Visual

limiting factor

population

ecosystem

predator

prey

habitat

species

carrying capacity

resource

degradation

reproduction

VOCABULARY

Limiting Factors

Limiting factors can include:

1. Competitors

Limiting Factors

Limiting factors can include:

1. Competitors

2. Disease and parasites

Limiting Factors

Limiting factors can include:

1. Competitors

2. Disease and parasites

3. Weather

Limiting Factors

Limiting factors can include:

1. Competitors

2. Disease and parasites

3. Weather

4. Fires

Limiting Factors

Limiting factors can include:

1. Competitors

2. Disease and parasites

3. Weather

4. Fires

5. Available habitat

Limiting Factors

Limiting factors can include:

1. Competitors

2. Disease and parasites

3. Weather

4. Fires

5. Available habitat

6. Predators

Competitors-organisms both cooperate and compete

Red-Tailed Hawk Barred Owl

•Birds of prey

•Live in forests on the edge of fields

•Eat mice and other rodents

•Nest in trees

Disease and Parasites

Diseases and parasites can be dependent on population size and habitat

Weather

StormsDroughtFloodingHeat/cold

Fires

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

Available Habitat

Human activities play a large role

Development, damming rivers, clear cutting forests.

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:

DATA: Effects of Resources on Deer Population

Year (round) Deer Population (#) # Resources

0    

1    

2    

3    

4    

5    

6    

7    

8    

9    

10    

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:

DATA: Effects of Natural Disturbances on Deer Population

Year (round) Deer Population (#) Resources (#) Events

0   

1   

2  

3   

4   

5   

6   

7   

8   

9   

10   

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:

DATA: Predation

Year (round) Deer Population (#) Predator (#)

0 8  11 12   22  16 4 3  16 8 4  12  125  4 16 6  2 4 7    

8    

9    

10    

REMEMBER: MR. DRY MIX

Graph 1: Effects of Resources on Deer

Population

Graph 2Effects of Natural Disturbances on Deer

Population

HIGHLIGHT MAJOR EVENTS

Graph 3Effects of Predation on Deer

Population

ANALYSIS QUESTIONS

1. List the basic needs of animals.

2. Describe the relationship between resource availability and population growth or decline.

3. Describe reasons for the fluctuation of the population.

4. Define “limiting factors” and provide three examples.

5. What is the carrying capacity for the deer population according to your graph?

6. Once the deer population goes significantly above carrying capacity, describe what happens to the deer population in the years following.

7. How did the introduction of a predator affect the deer population in terms of population size and deer behavior?

8. What was the peak population for the deer population when there were no predators? What happened after the peak? Why?

9. How might this “simulation” differ from the real relationship between deer and their environment? Write at least two differences and explain.

10. How do you think this “simulation” game differs from real predator-prey relationships? Explain.

Predators As the prey

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

Example: Lynx and Hare:

VIDEO: How the wolves changed the river?