1. Imagine a bus… How many people can you fit onto it?

2. How many extra people can it accommodate?

3. Graph Time (t) Population size (N) Write a story about what you can see happening in the graph.

4. Carrying capacity and limiting factors

5. Learning outcomes All of you will be able to: Identify possible limiting factors to population growth Most of you should be able to: Explain how limiting factors affect population growth in an ecosystem Explain the concept of carrying capacity in relation to limiting factors and population growth. Some of you might be able to: Relate this to the different tolerance ranges that species have

6. Carrying capacity? What do you think it means? Hint. It relates to ecosystems. An area or ecosystem can only sustainably support a certain number of organisms over a long period of time. The carrying capacity, is the number of organisms that a specific environment is able to carry.

7. The carrying capacity of an area / ecosystem is limited by… LIMITING FACTORS They prevent the unlimited growth of populations.

8. Limiting factors? Temperature Water availability Nutrient availability

9. http://www.otherwise.com/population/logistic.html

10. Checking learning outcomes Get out your learning outcome booklets… Who thinks they can explain the concepts of limiting factors and carrying capacity when talking about population growth?

11. Let’s do it… Write a short paragraph explaining the concepts of limiting factors and carrying capacity in the context of population growth… Remember to: Identify possible limiting factors Explain how these factors affect population growth Define the term carrying capacity Explain how the limiting factors influence the carrying capacity of an ecosystem

12. Population Growth J-curve Exponential growth Discuss what is happening… Typical of microbes, invertebrates, fish and small mammals

13. Human population growth

14. S-curve Discuss what is happening at each stage… Use the terms carrying capacity and limiting factors in your description. Transitional phase

15. Population growth J- and S-Curve

16. Exponential growth cane toad Bufo marinus in Australia

17. Bufo marinus population

19. Explosion–crash cycle

20. Starter In pairs… Use the whiteboards to sketch a J-curve and an S-curve. (Hint. Could be on the same axes) Be ready to explain what is happening in your graphs because I could pick on you!

21. Learning outcomes All of you will be able to: Sketch an S-curve and J-curve and describe you graphs. Most of you should be able to: Construct a suitable graph for the IB from the data provided. Interpret what the different graphs are illustrating using the key terms that you have seen.

22. Take the data provided and construct the graph. Look at the data first of all and decide if you will create a bar graph or a line graph. Remember the criteria we use when drawing a graph… 1. It occupies two thirds of the paper provided. 2. The scale is evenly spaced. 3. A pencil has been used. 4. A ruler has been used. 5. Both axes have been labelled accurately with units. 6. The graph has a suitable title. 7. Use crosses (+) not kisses (x).

23. Now… Write a story describing and explaining what you can see happening in your graph. Remember: include data when describing your graph and key terms when explaining it. Keep the description for yourself and switch your graph with the person next to you. Mark each others graphs based on the following criteria.

24. Graph mark scheme 1. It occupies two thirds of the paper provided. (1) 2. The scale is evenly spaced. (1) 3. A pencil has been used. (1) 4. A ruler has been used. (1) 5. Both axes have been labelled accurately. (1) 6. Units are included. (1) 7. The graph has a suitable title. (1) 8. Uses crosses (+). (1) 9. Points have been joined with a ruler. (1) Give them their score out of 9 marks

25. Now… Write a story describing and explaining what you can see in your neighbours graph. In pairs assess both your stories: 1. Have you used data from the graph when making your description? (2 marks for each story) 2. Have you included the key terms: exponential growth, carrying capacity and limiting factors? (3 marks) 3. Have you interpreted what is happening to the growth of each population… why does the S-curve level off? Why does the J- curve continue? (2 marks for each story)

26. Check - Learning outcomes All of you will be able to: Sketch an S-curve and J-curve and describe you graphs. Most of you should be able to: Construct a suitable graph for the IB from the data provided. Interpret what the different graphs are illustrating using the key terms that you have seen.