POPULATION ECOLOGY
Interaction of organisms with their physical and biological environment
Terminology
Species
Group of organisms with similar characteristics which can interbreed to
produce fertile offspring
Habitat
Specific type of environment (area) in which a plant or animal species
normally occur
Population
Group of organisms of the same species that occur in a particular area
in a particular time so that interbreeding occurs
Community
Group of populations occurring in a particular area e.g., lion, zebra and
giraffe in a National Park.
Ecosystem
Interaction between the biotic factors and abiotic factors in a particular
area
Ecology
Study of mutual interaction among living organisms and environment in
which they live
Biosphere
Part of the earth where living organisms are found.
Size of a population
the number of individuals in a population
Population density
the number of individuals of the population per unit of area
Population Density = Number of People
Land Area
The unit of land area should be square miles or square kilometers
,Population parameters
Mortality – death rate of a population expressed as the number of death per
thousand individuals per year
How do you calculate the mortality rate
1. Find the number of deaths and the population size reported during
the specified period.
2. Divide the number of deaths by the population size.
3. Choose the exponent, n.
4. Multiply the result by 10ⁿ (eg: 1000) to get the result per every 10ⁿ
people.
Natality – birth rate of a population expressed as the number of live per
thousand individuals per year
, Immigration – one-way movement of organisms into an area
Emigration – one-way movement of organisms out of an area
Migration – moves from one place to another and returns to the original
place
Impact of population parameters
Natality and immigration cause an increase in population size.
Mortality and emigration cause a decrease in a population size.
No immigration or emigration in a closed population e.g. animals on an
island. (The only parameters affecting population numbers will be births
or deaths)
Natality and mortality can affect the population size in a closed
population.
Interaction of organisms with their physical and biological environment
Terminology
Species
Group of organisms with similar characteristics which can interbreed to
produce fertile offspring
Habitat
Specific type of environment (area) in which a plant or animal species
normally occur
Population
Group of organisms of the same species that occur in a particular area
in a particular time so that interbreeding occurs
Community
Group of populations occurring in a particular area e.g., lion, zebra and
giraffe in a National Park.
Ecosystem
Interaction between the biotic factors and abiotic factors in a particular
area
Ecology
Study of mutual interaction among living organisms and environment in
which they live
Biosphere
Part of the earth where living organisms are found.
Size of a population
the number of individuals in a population
Population density
the number of individuals of the population per unit of area
Population Density = Number of People
Land Area
The unit of land area should be square miles or square kilometers
,Population parameters
Mortality – death rate of a population expressed as the number of death per
thousand individuals per year
How do you calculate the mortality rate
1. Find the number of deaths and the population size reported during
the specified period.
2. Divide the number of deaths by the population size.
3. Choose the exponent, n.
4. Multiply the result by 10ⁿ (eg: 1000) to get the result per every 10ⁿ
people.
Natality – birth rate of a population expressed as the number of live per
thousand individuals per year
, Immigration – one-way movement of organisms into an area
Emigration – one-way movement of organisms out of an area
Migration – moves from one place to another and returns to the original
place
Impact of population parameters
Natality and immigration cause an increase in population size.
Mortality and emigration cause a decrease in a population size.
No immigration or emigration in a closed population e.g. animals on an
island. (The only parameters affecting population numbers will be births
or deaths)
Natality and mortality can affect the population size in a closed
population.
