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POPULATION TREND - Coggle Diagram
POPULATION TREND
NATALITY
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they are the key factors in determining whether a population is increasing, decreasing or staying in the same size
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Types of Natality
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Absolute Natality - the number of births under ideal conditions (with no competition, abundance of resource such as food and water)
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MOERTALITY
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Is measured in rates usually expressed as the number of individuals that die in a given period (deaths per unit time) or the propotion of the population that dies in a given period (percents deaths per unit time)
A population theoretically has a minimum mortality - the theoretically minimum number of deaths in a population assuming no ecological constrains
The minimum mortality is always lower than the realized (or ecological) mortality, which is the observed number of losses in a population under actual environmental conditions
IMMIGRATION
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This individuals are of the same species as the rest of the population, and they increase the size of the population as they join the group
EMMIGRATION
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These may be juveniles who are heading out on their own, or it may be adults leaving the group for some other reason such as overcrowding or searching for new areas of food and shelter
Definition
refers to changes over time and can include changes in ranging behavior(eg : distance and route) and distribution, biogeography (eg : size of population) and life history (eg : birth and death rates)
changes in the size of population influenced by natality, mortality, immigration and emigration