When you come to the end of your rope, tie a knot and hang on. ~Franklin D. Roosevelt

1. When you come to the end of your rope, tie a knot and hang on.  ~Franklin D. Roosevelt

2. Exit Card • Name 3 general models that are used to estimate a population’s size. • How do element cycles (carbon, nitrogen, phosphorus, etc.) affect a population size • Should humans intervene with at-risk populations that have not been disturbed by humans?explain.

4. Population Distribution

5. density of population • measurement of population per unit area or unit volume.

6. Stable density population Who leaves more offspring a pair of elephants or a pair of rabbits? • How many of the five million eggs that a female cod might lay over the course of her life will, on average, survive and grow to adulthood?

7. Changing population density

8. Exponential Growth Model • Generation and generation – more offspring produced than parents. OR Immigration of species is occurring. • J-shaped curve-

9. “You decide to invest $1000 in a savings account. Your investment will grow at a rate of 10% each year. Assuming that you reinvest the interest each year, how much money will you have in 30 years?”

12. Doubling Time and the Rule of 70 • Calculating the time it will take for a population (or money) to double. • Exponential growth at a constant rate only • Divide 70 by the percentage growth rate.

13. If the population of rabbits in an ecosystem grows at a rate of approximately 4 percent per year, the number of years required for the rabbit population to double is closest to a. 4 years b. 8 years c. 12 years d. 17 years e. 25 years Solution: 70/4 = 17.5 years, the closest answer to 17.5 would be “d” 17 years.

14. Logistic Growth Model • Logistic growth- when a population whose growth is initially exponential, but slows as the population approaches the carrying capacity. • S-shaped curve- when graphed the logistic growth model produces an “S”.

15. What influences carrying capacity? Density Dependent factors : (pop density is affected because of its size) • Food supply • Habitat for living and breeding • Parasitism • Predation risk

16. Extreme Animal Myth • Do Lemmings take density depended factors too far? And go into madness?

18. What influences carrying capacity? • Density Independent Factors: (pop density is affected regardless of its size) • Natural disasters (floods earthquakes, fires • Human hunting • Changes in chemicals present

19. Management • What type of growth model is the elephant population illustrating? • Explain two concerns with this and its likely outcome if continued • What is the reproductive strategy of the elephant (r-selected or k-selected?(explain your answer) • Draw a survivorship curve that best exhibits that best exhibits the elephants lifetime survivorship. • Create a plan to stabilize the population of the elephants.

20. Management • What type of growth model is the elephant population illustrating? Exponential Growth Model 2. Explain two concerns with this and its likely outcome if continued Disease or starvation = concerns Likely outcome is a population crash 3. What is the reproductive strategy of the elephant (r-selected or k-selected?(explain your answer) K-selected 4. Draw a survivorship curve that best exhibits that best exhibits the elephants lifetime survivorship. 5. Create a plan to stabilize the population of the elephants.

22. Predator Prey Relationship