1. Limiting Factors and Carrying Capacity DO NOW WEDNESDAY Explain what limiting factors are. Give some examples. What is carrying capacity?

2. Scenario In 1970 the deer population of an island forest reserve about 518 square kilometers in size was about 2000 animals. Although the island had excellent vegetation for feeding, the food supply obviously had limits. Thus the forest management personnel feared that overgrazing might lead to mass starvation. Since the area was too remote for hunters, the wildlife service decided to bring in natural predators to control the deer population. It was hoped that natural predation would keep the deer population from becoming too large and also increase the deer quality (or health), as predators often eliminate the weaker members of the herd. In 1971, ten wolves were flown into the island. Objective: How a Predator-Prey Population Changes Over Time Key Words: Natural Resources, Limiting Factors, Carrying Capacity

3. Results of the program The results of this program are shown in the following table. Data Table Trials (years)1971197219731974197519761977197819791980 Number of Deer2,0002,3002,5002,3602,2242,0941,9681,9161,9521,972 Number of Wolves101216222824211819 1. Graph the deer and wolf populations on the graph below in a graph line. Use one color to show deer population and another color to show wolf population. Objective: How a Predator-Prey Population Changes Over Time Key Words: Natural Resources, Limiting Factors, Carrying Capacity

4. Conclusions 2. How did the deer and wolf populations change over time? Deer and Wolf Populations from 1971 to 1980 Deer and wolf populations first increased, then decreased, and then became stable. Objective: How a Predator-Prey Population Changes Over Time Key Words: Natural Resources, Limiting Factors, Carrying Capacity

5. d. Discussion 3. Once the wolves were introduced, what is the carrying capacity for deer and wolves in the ecosystem? 4. What do you think would have happened to the deer on the island if the wolves had NOT been introduced? Deer and Wolf Populations from 1971 to 1980 Deer’s carrying capacity is 1960. Wolf’s carrying capacity is 19. Initially, deer’s population would increase because there would be no predators. Then, deer’s population would decrease, because deer would have used up all of the resources and then starve to death. Objective: How a Predator-Prey Population Changes Over Time Key Words: Natural Resources, Limiting Factors, Carrying Capacity

6. d. Discussion 5. What limiting factors affect deer population? 6. What limiting factors affect wolf population? Deer and Wolf Populations from 1971 to 1980 Water, food, shelter, predators, diseases, and climate. Water, food, shelter, diseases, and climate. Objective: How a Predator-Prey Population Changes Over Time Key Words: Natural Resources, Limiting Factors, Carrying Capacity

7. d. Discussion 7. How would you describe the relationship between the deer and wolf population? Deer and Wolf Populations from 1971 to 1980 Deer and wolf populations depend on each other. Both show the same pattern: increase and decrease, then become stable. Objective: How a Predator-Prey Population Changes Over Time Key Words: Natural Resources, Limiting Factors, Carrying Capacity More wolves Less wolves More deer Less deer Deer and wolf populations depend on each other.

8. d. Discussion 8. Would you agree or disagree with the following statement. “Predators and prey exist in a balance.” Explain. Deer and Wolf Populations from 1971 to 1980 Agree, because… Or disagree, because… Objective: How a Predator-Prey Population Changes Over Time Key Words: Natural Resources, Limiting Factors, Carrying Capacity

9. d. Discussion 9. What are the advantages of having a population of predators and prey in an ecosystem? Deer and Wolf Populations from 1971 to 1980 It increases biodiversity and makes the ecosystem more stable. Predators keep the deer population from becoming too large and prevent mass starvation. Predators increase the deer health, as predators often eliminate the weaker members of the herd. Objective: How a Predator-Prey Population Changes Over Time Key Words: Natural Resources, Limiting Factors, Carrying Capacity

10. 10. In certain areas of the United States, the populations of wolves and other predators have decreased. As a result, deer populations in these areas have increased. Describe one way that an increase in the deer population can be harmful to humans. They transmit diseases to humans, i.e. Lyme disease. They cause automobile accidents. They eat crops. Objective: How a Predator-Prey Population Changes Over Time Key Words: Natural Resources, Limiting Factors, Carrying Capacity