1. Population Ecology

2. Population Dynamics Population Density: number of organisms per area.
Dispersion: the pattern of spacing of a population within an area

3. Dispersion: the pattern of spacing of a population within an area
Uniform dispersion: black bears
Clumped: bison
Random: deer

4. Limiting Factors:
Factors that keep a population from continuing to increase in numbers indefinitely.
Density independent factors
Density dependent factors

5. Density Independent Factors:
Any factor in the environment that doesn’t depend on the number of members of a population per unit area.
Usually abiotic or part of natural phenomena, such as weather events
Drought, extreme temperatures, tornados, hurricanes

6. Density Dependent Factors
Any factor in the environment that depends on the number of members in a population per unit area.
Biotic Factors: Disease, Competition, Parasites

7. Studying Dispersion and Population Density
Quadrat Sampling: using a known small area to count the number of organisms within that area. This count is then used to generate data for a larger area.
Random Sampling:
Line Transect Sampling:
Mark and Recapture:

9. Growth Rates Population Growth Rate: how fast a population grows.
Takes into account the natality (birth) and mortality (death) rates.
Emigrations: the number of organisms moving away from a population
Immigration: the number of organisms moving into a population
Usually emigration=immigration

10. Exponential Growth Model
Population grows exponentially and passes its carrying capacity until some limiting factor slows the growth.

11. Logistic Growth Model
Occurs when the population’s growth slows or stops following exponential growth, at the population’s carrying capacity.

12. Reproductive Patterns: R/K Selection Theory
r-Strategists: rate strategy: orgainisms that live in environments with fluctuations in biotic and abiotic factors occur.
Generally small organisms, short life spans and produce many offspring.
Usually controlled by density independent factors and do not maintain carrying capacity
Bacteria, insects and weeds
Follow exponential growth models

13. K- strategists: carry capacity strategy: organisms that live in a predictable environment that does not change greatly from year to year.
Generally larger orgainisms, long lifespans, few offspring, reaches equillibrium at carrying capacity. Great amounts of parental care
Humans, elephants
Follow logistic growth models

14. Human Population Growth
Demography: the study of human population size, density, distribution, movement, and birth and death rates.

15. Human Population Growth:
Why is the population growth decreasing???

16. Zero Population Growth: the birth plus immigtation equals the death plus emigration.
Births and deaths occur at the same rate. The age structure of the population becomes equal.

17. Age Structure
The number of males and females in each of three age groups: pre-reproductive (under 20), reproductive (20-44), and post reproductive (above 44)