3. Tuesday May 3, 2011 Objective: Students will be able to describe population growth Bellringer: 1.What is a population? 2.What is the current size of Earth’s human population? 3.(On Monday: “No BR”)

4. 4 MINUTES REMAINING…

5. Tuesday May 3, 2011 Objective: Students will be able to describe population growth Bellringer: 1.What is a population? 2.What is the current size of Earth’s human population? 3.(On Monday: “No BR”)

6. 3 MINUTES REMAINING…

7. Tuesday May 3, 2011 Objective: Students will be able to describe population growth Bellringer: 1.What is a population? 2.What is the current size of Earth’s human population? 3.(On Monday: “No BR”)

8. 2 MINUTES REMAINING…

9. Tuesday May 3, 2011 last chance to view BR - 1 min Objective: Students will be able to describe population growth Bellringer: 1.What is a population? 2.What is the current size of Earth’s human population? 3.(On Monday: “No BR”)

10. 30 Seconds Remaining…

11. 10 Seconds Remaining…

12. Last Call for Bellringers! Cookie Monster… mmmmmm…

13. Tuesday May 3, 2011 Bellringer Review Objective: Students will be able to describe population growth Bellringer: 1.What is a population? 2.What is the current size of Earth’s human population? 3.(On Monday: “No BR”)

14. Tuesday May 3, 2011 AGENDA: 1.BR 2.Notes: Population Growth 3.Problem Set 4.Brainpop HOMEWORK Population Growth Problem Set

15. Section 4.1 Summary – pages 91-99 A population is a group of organisms, all of the same species, that live in a specific area. A healthy population will grow and die at a steady rate unless it runs out of food or space, or is attacked in some way by disease or predators. Principles of Population Growth Scientists study changes in populations in a variety of ways.

16. Section 4.1 Summary – pages 91-99 One method involves introducing organisms into an environment that contains abundant resources and then watching how the organisms react. Principles of Population Growth

17. Section 4.1 Summary – pages 91-99 Studies of populations of larger organisms, such as an elk population in a national park, require methods such as the use of radio monitors. Principles of Population Growth

18. Section 4.1 Summary – pages 91-99 The growth of populations is unlike the growth of pay you get from a job. Populations of organisms, do not experience linear growth. Rather, the graph of a growing population starts out slowly, then begins to resemble a J-shaped curve. How fast do populations grow?

19. Section 4.1 Summary – pages 91-99 How fast do populations grow? Population Growth of Houseflies 1 million 500,000 100 One year Population size

20. Section 4.1 Summary – pages 91-99 The initial increase in the number of organisms is slow because the number of reproducing individuals is small. Soon, however, the rate of population growth increases because the total number of individuals that are able to reproduce has increased. How fast do populations grow?

21. Section 4.1 Summary – pages 91-99 A J-shaped growth curve illustrates exponential population growth. Exponential growth means that as a population gets larger, it also grows at a faster rate. Is growth unlimited? Exponential growth results in unchecked growth.

22. Section 4.1 Summary – pages 91-99 Limiting factors, such as availability of food, disease, predators, or lack of space, will cause population growth to slow. Under these pressures, the population may stabilize in an S-shaped growth curve. What can limit growth?

23. Section 4.1 Summary – pages 91-99 What can limit growth?

24. Section 4.1 Summary – pages 91-99 The number of organisms of one species that an environment can support indefinitely is its carrying capacity. When a population overshoots the carrying capacity, then limiting factors may come into effect. Carrying capacity Click image to view movie.

25. Section 4.1 Summary – pages 91-99 Carrying capacity Deaths begin to exceed births and the population falls below carrying capacity. Carrying capacity

26. Section 4.1 Summary – pages 91-99 Predation affects population size The data in this graph reflect the number of hare and lynx pelts sold to the Hudson’s Bay Company in northern Canada from 1845 through 1935. Lynx and Hare Pelts Sold to the Hudson’s Bay Company Number of organisms(in thousands) Times (in years) Lynx Hare