Strand 1: Environmental studies………………………………………………………………………………………
Strand 1:
Population ecology
Surviourship curves
Predator-prey relationships
Competition
Ecological succession
Social organisation
Human population dynamics
What is population ecology?
Ecology The study of the interactions of organisms with
their physical and biological environments and
how these determine the distribution and make up
of populations within an ecosystem
Population ecology Concerned with fluctuations in the size of a
population and the physical and social factors
which regulate these fluctuations
individual A single organism that forms part of a species
Species A group of organisms with similar characteristics,
which produce fertile offspring
Population A group of organisms of the same species that
are found in a particular area and can crossbreed
freely
Community A group of populations occurring in a particular
area
ecosystem A unit of l-plant and animal communities
(biotic/living) in interaction with each other as well
as with the non-living(abiotic) factors in a
particular area
enviroment The external factors, living (biotic) and non-
living(abiotic), surrounding an organism and
influencing its development and survival
habitat The specific environment(home) in which a plant
or animal species normally occurs
Factors affecting the size of a population
Population size Total number of individuals in a population
, Natality birth rate of a population
Increase population
Morality Death rate of a population
Decrease of a population
immigration The one way movement of organisms into an area
where they become established
immigration=into
emigration The one way movement of organisms out of an
area were they became established
Emigration= exit
Closed population Immigration and emigration do not occur
The only parameters affecting population size are
natality and morality
How is the growth of a population regulated
As the number of organisms increases More demands= increase in environmental
resistance
Environmental resistance The total number of factors that stop a population
from reproducing at its maximum rate
Carrying capacity The population density that the enviroment can
support (the max number of individuals that a
specific environment can sustain)
Stable and unstable populations
A stable population is a population where the Population increase beyond carrying capacity
numbers fluctuate around carrying capacity >enviromental resistance (limiting factors) will
increase
>overall population will decrease
Population decrease below carrying capacity
>enviromental resistanc will decrease
>overall population will increase
An unstable population is a population where the The habitat will most likely be damaged and
population numbers far exceed the carrying deteriorate rapidly
capacity
Fluctuation causes:
Seasonal Size of population flucutates from one season to
another
Some species fly to warmer climates and increase
their population (e.g European barn swallow)
annual Fluctuates over different times of the year
Migration can be based on availability of grazing
and this is dependant on rainfall
Strand 1:
Population ecology
Surviourship curves
Predator-prey relationships
Competition
Ecological succession
Social organisation
Human population dynamics
What is population ecology?
Ecology The study of the interactions of organisms with
their physical and biological environments and
how these determine the distribution and make up
of populations within an ecosystem
Population ecology Concerned with fluctuations in the size of a
population and the physical and social factors
which regulate these fluctuations
individual A single organism that forms part of a species
Species A group of organisms with similar characteristics,
which produce fertile offspring
Population A group of organisms of the same species that
are found in a particular area and can crossbreed
freely
Community A group of populations occurring in a particular
area
ecosystem A unit of l-plant and animal communities
(biotic/living) in interaction with each other as well
as with the non-living(abiotic) factors in a
particular area
enviroment The external factors, living (biotic) and non-
living(abiotic), surrounding an organism and
influencing its development and survival
habitat The specific environment(home) in which a plant
or animal species normally occurs
Factors affecting the size of a population
Population size Total number of individuals in a population
, Natality birth rate of a population
Increase population
Morality Death rate of a population
Decrease of a population
immigration The one way movement of organisms into an area
where they become established
immigration=into
emigration The one way movement of organisms out of an
area were they became established
Emigration= exit
Closed population Immigration and emigration do not occur
The only parameters affecting population size are
natality and morality
How is the growth of a population regulated
As the number of organisms increases More demands= increase in environmental
resistance
Environmental resistance The total number of factors that stop a population
from reproducing at its maximum rate
Carrying capacity The population density that the enviroment can
support (the max number of individuals that a
specific environment can sustain)
Stable and unstable populations
A stable population is a population where the Population increase beyond carrying capacity
numbers fluctuate around carrying capacity >enviromental resistance (limiting factors) will
increase
>overall population will decrease
Population decrease below carrying capacity
>enviromental resistanc will decrease
>overall population will increase
An unstable population is a population where the The habitat will most likely be damaged and
population numbers far exceed the carrying deteriorate rapidly
capacity
Fluctuation causes:
Seasonal Size of population flucutates from one season to
another
Some species fly to warmer climates and increase
their population (e.g European barn swallow)
annual Fluctuates over different times of the year
Migration can be based on availability of grazing
and this is dependant on rainfall
