1. Population Ecology

2. Population Essential Questions What factors influence populations in ecosystems? How do human population dynamics affect the world we live in?

3. What is a population? A group of the same species living in a geographic area Important Note: So a population is made up of individuals. But, multiple populations make up a community.

4. Quantifying Population Three key features: – Population size – Population density – Population distribution

5. Population Size Number of individuals in an region

6. Population Density Number of individuals within a population per unit area

8. Population Distribution The spatial arrangement of organisms within an area clumped uniform random

9. Population Distribution

11. Unregulated populations increase by exponential growth Quick Think: In this model, a population will get bigger and bigger forever! Do you think that is really possible?

12. Logistic Growth Model Carrying Capacity (K) Quick Think: What are some things that may cause population growth to slow down?

13. Limiting factors prevent endless population growth Limiting factors: physical, chemical, and biological characteristics of the environment that restrain population growth Limiting factors are also referred to as “environmental resistance” Carrying capacity: maximum population size that the environment can sustain Quick Think: Is the carrying capacity the same for all populations? Why or why not?

14. Examples of limiting factors Space Sunlight Availability of: – Food – Water – Mates and breeding sites – Shelter Temperature Nutrients Pollutants

15. The influence of some factors depends on population density Density-dependent factors Disease Competition Finding mates Parasites Density-independent factors Temperature Storms Habitat Destruction Drought

16. Reproductive strategies Biotic potential – ability to produce offspring