1. Population growth

2. Can we grow forever? No, because…Yes, because…

3. Global Human population Population growth patterns Changes in population occur when individuals are added to or removed from a population. Population growth=(birth+immigration)– (deaths+emigration)

4. Carrying Capacity 1.Ultimately all populations are limited by the amount of usable energy from sun, water, carbon 2. Populations are limited by their food supply. Entire food web is affected if there is a shift in available organisms to feed on.

5. Cont’d 3.

6. Limits on population 1.Biotic potential: The maximum number of offspring that a species could produce. 2.Carrying capacity: The maximum number of individuals of a species that can be supported indefinitely by an ecosystem. 3.Law of minimum: Where the nutrient in least supply is the one that limits growth. 4.Law of tolerance: an organism can survive within a certain range of an abiotic factor.

7. Factors that cause changes in population Density independent factors: (affect population regardless of density) –Flood –Fire –Spraying of pesticides –Change in climate –Change in temperature –Destruction of habitat –drought Density dependent factors: (affect population because of the density) –Food storage –Competition for mates –Breeding areas (habitat) –Disease caused by a microorganism or parasite –Introduction of an exotic species –Increased predation –Competition for water and other resources.

8. Plotting yeast cell growth Yeast are single-celled fungi that use sugar as a food supply. When deprived of oxygen, they convert sugar to carbon dioxide gas and alcohol. This reaction releases energy, and the yeast use that energy to grow and reproduce rapidly.

9. Graph the following 1.Use the data to plot a line graph of time (on the horizontal axis) against the number of yeast cells (on the vertical axis). 2.Describe the shape of the graph. 3.Explain and give reasons for the population pattern from days 1-6. 4.Explain what might have caused the change in the growth pattern from day 7 through day 9. Time (days) 123456789 Number of yeast cells (per mL) 23819336844120

10. What information needs to be on your graph Graph # Appropriate title Label axis with units