2. AP Biology Population Ecology population ecosystem community biosphere organism

3. AP Biology Life takes place in populations  Population  group of individuals of same species in same area at same time  rely on same resources  interact  interbreed  rely on same resources  interact  interbreed Population Ecology: What factors affect a population?

4. AP Biology  Abiotic factors  sunlight & temperature  precipitation / water  soil / nutrients  Biotic factors  other living organisms  prey (food)  competitors  predators, parasites, disease  Adaptations Factors that affect Population Size

5. AP Biology Population Range  Geographical limitations  abiotic & biotic factors  temperature, rainfall, food, predators, etc.  habitat adaptations to polar biome adaptations to rainforest biome

6. AP Biology External Factors  Directly affect organisms, populations and communities Affect the availability of resources Organisms must adapt to survive

7. AP Biology External Factors  Natural disasters affect organisms and resources.  Populations are interrelated and affect one another.

8. AP Biology Competition  When two organisms require the same resource to meet their needs.  Competition contributes to limited population growth for biotic factors involved.

9. AP Biology Competition  Intraspecific competition – organisms of the same species compete for resources.  Interspecific competition – occurs between different species for resources within an ecosystem.

10. AP Biology Population Size  Changes to population size  adding & removing individuals from a population  birth  death  immigration  emigration

11. AP Biology African elephant protected from hunting Whooping crane coming back from near extinction Exponential growth rate  Characteristic of populations without limiting factors  Conditions that affect the growth rate and size of populations and communities

12. AP Biology Logistic rate of growth  Can populations continue to grow exponentially? Of course not! no natural controls effect of natural controls

13. AP Biology Regulation of population size  Limiting factors  density dependent  competition: food, mates, nesting sites  predators, parasites, disease  density independent  abiotic factors  sunlight (energy)  temperature  rainfall swarming locusts marking territory = competition competition for nesting sites

14. AP Biology 500 400 300 200 100 0 2001030504060 Time (days) Number of cladocerans (per 200 ml)  The number of individuals in a population that the environment can support. Time (years) 1915192519351945 10 8 6 4 2 0 Number of breeding male fur seals (thousands) Carrying capacity What ’ s going on with the plankton?

15. AP Biology Changes in Carrying Capacity  Population cycles  predator – prey interactions At what population level is the carrying capacity? K K K K

16. AP Biology biosphere ecosystem community population Studying organisms in their environment organism

17. AP Biology 2007-2008 Any Questions?