1. Ecology of Populations

2. What is Ecology? Ecological levels Organism – An individual
Population – Individuals of the same species
Community – Different populations in one location
Ecosystem – Community of populations and their interactions with the environment (abiotic factors)

3. Coral Reef as an Ecosystem

4. Density and distribution
Demographics-
Density and distribution
Population density – pattern of dispersal of individuals across an area of interest
Resources – abiotic (nonliving) and biotic (living) components of environment
Limiting factors – environmental aspects that determine where an organism lives

5. Population Characteristics
Population Ecology: Population Characteristics
Population Characteristics
Population Density:
The number of organisms per unit area
Spatial Distribution:
Dispersion: The pattern of spacing a population within an area
3 main types of dispersion
Clumped
Uniform
Random
The primary cause of dispersion is resource availability

6. Population Limiting Factors
Population Ecology: Population Characteristics
Population Limiting Factors
Population growth rate
How fast a given population grows
Factors that influence this are:
Natality (birthrate)
Mortality (_____ rate)
Emigration (the number of individuals moving _________ a population)
Immigration (the number of individuals _________ a population)
death
away from
moving to

7. Population Limiting Factors
Population Ecology: Density-independent factors
Population Limiting Factors
Density-independent factors
Factors that limit population size, regardless of population density.
These are usually abiotic factors
They include natural phenomena, such as weather events
Drought, flooding, extreme heat or cold, tornadoes, hurricanes, fires, etc.

8. Population Limiting Factors
Population Ecology: Density-dependent factors
Population Limiting Factors
Density-dependent factors
Any factor in the environment that depends on the number of members in a population per unit area
Usually biotic factors
These include
Predation
Disease
Parasites
Competition

9. Community Ecology: Communities
Review:
A community is a group of interacting populations that occupy the same area at the same time.

10. Communities Limiting Factors
Community Ecology: Communities
Communities
Limiting Factors
Any abiotic or biotic factor that restricts the numbers, reproduction, or distribution of organisms.

11. Communities Range of Tolerance
Community Ecology: Communities
Communities
Range of Tolerance
The limits within which an organism can exist.

12. 1. Which of the following lists include only abiotic environmental factors?
a. food, temperature, fire, wind
b. soil, light, predators, oxygen levels
c. wind, rainfall, temperature, soil
d. light, food, predators, plants
2. Which of the following descriptions about the organization of an ecosystem is correct?
a. communities make up species, which make up populations
b. populations make up species, which make up communities
c. species make up communities, which make up populations
d. species make up populations, which make up communities
3. Which of the following would represent an ecosystem?
a. A food chain b. The physical features of rainforest
c. A prairie d. All of these
4. Which of the following food chains correctly shows the path of matter and energy through the ecosystem?
a. deer – bear – grass b. grass – deer - bear
c. seeds – bear – chipmunk d. chipmunks – seed – deer