Download Ecology - Intro to Zoology

Ecology of Populations
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)
Coral Reef as an Ecosystem
DemographicsDensity 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
Population Ecology: Population Characteristics
Population Characteristics
1. Population Density:
–
The number of organisms per unit area
2. 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
Population Ecology: Population Characteristics
Population Limiting Factors
3. Population growth rate
– How fast a given population grows
– Factors that influence this are:
•
•
•
•
Natality (birthrate)
death rate)
Mortality (_____
Emigration (the number of individuals moving
_________
away from a population)
Immigration (the number of individuals _________
moving to a
population)
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.
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
Community Ecology: Communities
Communities
• Review:
– A community is a group of interacting populations
that occupy the same area at the same time.
Community Ecology: Communities
Communities
• Limiting Factors
– Any abiotic or biotic factor that restricts the
numbers, reproduction, or distribution of
organisms.
Community Ecology: Communities
Communities
• Range of Tolerance
– The limits within which an organism can exist.
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
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
•
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
•
•
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