Population Ecology
Definitions:
ECOLOGY
Interactions of organisms with biological and physical (biotic and abiotic) components of their environments.
Population ecology-The study of fluctuations in population size and the factors
1. Individual-a single organism a plant or animal living in an environment/ A single organism capable of
independent existence
2. Species-a group of organisms with similar characteristics living in an area and can produce viable offspring
3. Population is a group of species living in an area at a particular time and able to produce viable offspring.
Or A group of organisms of the same species ✓ occupying a definable area ✓ close enough for random
interbreeding. ✓ (3)
4. Community a group of different population that live together and interact in an area or
Community – group of populations/species in an area. Ecosystem includes interaction with environment / groups
communities interacting with each other.
Or
Two or more different species occupying the same geographical area and in a particular time.
Ecosystem: all organisms that live in an area and interact with each other with nonliving organisms/ Groups of di
species (‘populations’) that interact with each other and the environment.
,Population size
Factors that affect population size-
Natality -birth rate in animals/plants mortality death rate
Immigration- movement of organisms into an area and stay
Emigration- movement of organisms out of an area and do not return
EnviroStudies1 Population Ecology
,Growing population sizes
Increases when Birth rate and immigration exceed death and emigration
Decline when death and emigration exceed natality and immigration
Remain the same when birth rate and immigration equal to mortality emigration
Factors that affect Population size
mortality
Pop size
natality
emigration
popsize
immigration
EnviroStudies1 Population Ecology
, Population parameters
Are the factors that affect pop size
E.g., natality and immigration
Mortality and emigration
Types of population
Closed population- is when organism is not allowed to move into and out of the area
Open population- where there is free movement of organisms into and out of the area
Limiting factors
Are factors that reduce population size
These are
1. .Density dependent factors
2. Density independent factors
Density dependent factors
Factors that are caused by organism themselves in an area as pop growth e.g., diseases, space, crowded shelter
Density independent factors are natural factors that affect population size e.g.
Drought, temperature, floods etc.
EnviroStudies1 Population Ecology
Definitions:
ECOLOGY
Interactions of organisms with biological and physical (biotic and abiotic) components of their environments.
Population ecology-The study of fluctuations in population size and the factors
1. Individual-a single organism a plant or animal living in an environment/ A single organism capable of
independent existence
2. Species-a group of organisms with similar characteristics living in an area and can produce viable offspring
3. Population is a group of species living in an area at a particular time and able to produce viable offspring.
Or A group of organisms of the same species ✓ occupying a definable area ✓ close enough for random
interbreeding. ✓ (3)
4. Community a group of different population that live together and interact in an area or
Community – group of populations/species in an area. Ecosystem includes interaction with environment / groups
communities interacting with each other.
Or
Two or more different species occupying the same geographical area and in a particular time.
Ecosystem: all organisms that live in an area and interact with each other with nonliving organisms/ Groups of di
species (‘populations’) that interact with each other and the environment.
,Population size
Factors that affect population size-
Natality -birth rate in animals/plants mortality death rate
Immigration- movement of organisms into an area and stay
Emigration- movement of organisms out of an area and do not return
EnviroStudies1 Population Ecology
,Growing population sizes
Increases when Birth rate and immigration exceed death and emigration
Decline when death and emigration exceed natality and immigration
Remain the same when birth rate and immigration equal to mortality emigration
Factors that affect Population size
mortality
Pop size
natality
emigration
popsize
immigration
EnviroStudies1 Population Ecology
, Population parameters
Are the factors that affect pop size
E.g., natality and immigration
Mortality and emigration
Types of population
Closed population- is when organism is not allowed to move into and out of the area
Open population- where there is free movement of organisms into and out of the area
Limiting factors
Are factors that reduce population size
These are
1. .Density dependent factors
2. Density independent factors
Density dependent factors
Factors that are caused by organism themselves in an area as pop growth e.g., diseases, space, crowded shelter
Density independent factors are natural factors that affect population size e.g.
Drought, temperature, floods etc.
EnviroStudies1 Population Ecology
