1. LIMITING FACTORS establish an ecosystems
CARRYING CAPACITY, the population size the ecosystem can support at any given time

2. Limits turn a J shaped curve into an S shaped curve

3. Density independent limiting factors
Affect any size population
Ex: disasters like floods affect populations & members indiscriminately, regardless of pop. size or individual ‘fitness’

4. Density dependent limiting factors related to population size
• ex: disease more effective in a crowded population
• Can lead to selection of the ‘fittest’
delta.pmhclients.com
Worse as pop more dense
Less impact on small pop

5. Ex: Galapagos finches:1976 drought
seed abundance changes seed hardness changes
Finch population size decreases
Finch beak type shifts
Seed abundance
Number of birds
Seed hardness
Beak depth

6. Ex: predator - prey population interactions
Lag time
prey
predator

7. Lynx/Snowshoe hare dynamics