1. Population Ecology

2. Levels of Ecological Organization

3. HABITAT – Where organism lives
NICHE – An organism’s role in a community and the resources that it uses
Specialist – Species with a narrow niche….have very specific requirements
Example: Panda
Generalist – Species with a broad niche – able to use wide variety of habitats and resources

4. Population Characteristics
SIZE – Number of organisms present at a given time
Extinctions often preceded by DECLINE in population size

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

6. Population Distribution
Spatial arrangement of organisms within an area

7. Populations may grow, shrink, or remain stable
Births within the population (natality)
Deaths within the population (mortality)
Immigration – arrival of individuals from outside the population
Emigration – departure of individuals from the population

8. Growth Rate of Population
Express birth and death rates per 1,000 individuals for a given time period.
Referred to as “Crude” birth rate or death rate
Growth Rate = (Crude birth rate + immigration rate) – (Crude death rate + emigration rate)
Example: (18/ /1000) – (10/ /1000) = 6/1000
This population of 1000 in one year will reach 1006 in next year.
Growth Rate is expressed as percentage: Growth rate x 100%
6/1000 x 100% = 0.6%

9. Exponential Growth
Unregulated populations increase by exponential growth (fixed percentage each year)
J shaped growth curve
Occurs when organisms introduced to “new” environment
Examples: Mold growing on piece of bread,
Bacteria colonizing
recently dead animal,
Scots Pine tree after
retreat of glaciers

10. Logistic Growth Limiting factors restrain population growth
S shaped growth curve

11. Limiting Factors
Density Dependent – Limiting factors that have stronger effect on large, dense populations than small, less crowded populations
Ex: Disease, Predation, Competition for resources food, water, space
Density Independent - Same effect regardless of population size
Ex: Natural disasters floods, fires, hurricanes, etc. and extremes in temperature
Carrying Capacity – Maximum population size of a species that a given environment can support

12. Biotic Potential and Reproductive Strategies

13. Survivorship Curves

14. Conservation of Biodiversity
Creating Protected Areas for endangered species – National Parks and Reserves
Ecotourism