limiting factors ecosystems sc.912.l.17.5 essential question: how do abiotic (physical) limiting...
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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?