Limiting Factors Ecosystems SC 912 L 17 5

Limiting Factors Ecosystems SC. 912. L. 17. 5 ESSENTIAL QUESTION: How do abiotic (physical) limiting factors affect growth and survival in an ecosystem ?

Let’s suppose…. l 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…. . l We’d be over-run with mice on the planet!! Why doesn’t this occur?

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

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

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

Limiting Factors l 1. Limiting factors can include: Competitors

Limiting Factors l 1. 2. Limiting factors can include: Competitors Disease and parasites

Limiting Factors l 1. 2. 3. Limiting factors can include: Competitors Disease and parasites Weather

Limiting Factors l 1. 2. 3. 4. Limiting factors can include: Competitors Disease and parasites Weather Fires

Limiting Factors l 1. 2. 3. 4. 5. Limiting factors can include: Competitors Disease and parasites Weather Fires Available habitat

Limiting Factors l 1. 2. 3. 4. 5. 6. Limiting factors can include: Competitors Disease and parasites Weather Fires Available habitat Predators

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

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

Weather l. Storms l. Drought l. Flooding l. Heat/cold

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

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

HOT LAB: Limiting Factors Problem Statement: l 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 7 21 1 14 14 2 20 8 3 18 11 4 22 7 5 13 16 6 28 1 7 2 27

HOT LAB: Limiting Factors Problem Statement: l 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 (#) 0 7 1 14 2 24 3 12 4 14 5 28 6 2 7 4 8 8 9 4 Resources (#) Events 21 14 5 17 Flood 15 1 27 25 21 25 drought

HOT LAB: Limiting Factors Problem Statement: l 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 7 1 1 8 4 2 6 6 3 6 1 4 8 2 5 6 7

ANALYSIS QUESTIONS 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 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.

Predators l 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?