1. Populations

2. Rates That Affect Population Size Natality- the birth rate; the number of births over time Mortality- the death rate; the number of deaths over time

3. Rates That Affect Population Size Immigration- the rate of individuals entering the population from a different population; the number of individuals entering over time Emigration- the rate of individuals leaving a populations to go to a different population; the number of individuals leaving a population

4. Population Growth Two Types of Growth: – Exponential – Logistic

5. Exponential Growth Occurs when the individuals in a population reproduce at a constant rate Under ideal conditions with unlimited resources, a population will grow exponentially

6. Exponential Growth J-Curve

7. Logistic Growth Occurs when a population's growth slows or stops following a period of exponential growth

8. Logistic Growth S-Curve

9. Carrying Capacity- the maximum population size that environment can sustain. – Usually determined by a limiting factor As resources become less available the growth of a population slows or stops.

10. New or early populations show exponential growth Old, stable populations show no growth, but stay near the carrying capacity of the environment

11. What happens if a population exceeds its carrying capacity?

12. If a population exceeds the carrying capacity of its environment, the carrying capacity decreases

13. Human Population Is the human population growing exponentially or logistically?

14. Niches and Communities Niche - range of physical and biological conditions in which a species lives and the way the species obtains what it needs to survive and reproduce. Different Factors: – Tolerance – ability to survive and reproduce under a range on environmental circumstances.

15. Tolerance Graph

16. Niche cont. Resources – food, water, nutrients, etc Physical – abiotic factors Biological – biotic factors Competition – exactly what you would think Competitive Exclusion Principle – no two species can occupy exactly the same niche in exactly the same habitat at exactly the same time.

17. Predator-Prey Relationships Predation – interaction in which one animal (predator) eats another animal (prey) – Predators affect the size of prey populations within a community and determine the places where the prey can live. Herbivory – Same concept at predation just with plants

18. Predator-Prey Graph

19. Symbioses Two creatures living in harmony and helping each other survive. Mutualism – both benefit (Clown fish – Anemone) Parasitism – one organisms lives inside or on another organisms and harms it (Tapeworms) Commensalism – one organism benefits and the other is neither harmed nor helped. (Barnacles and Whales)