Greyson Piesco
Topic 5.3: Populations
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Population size is effected by... Natality: this is an increase in the number of births so the population will increase as a result Immigration: this is people coming into a population so the population will increase as a result Mortality: this is death in a population, so population will decrease as a result
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Differences in Growth Phases
Exponential: -There is a rapid increase in the size of a population -This is due to natality exceeding mortality and immigration exceeding emigration -In order to support such a growth, food, water, and shelter have to be readily available Transitional: -Here natality begins to level off and mortality increases -Resources become less plentiful -Disease and predators increase -Immigration slows, but still is higher than emigration -There is still growth, but at a much slower rate Plateau: -Natality and Mortality are relatively even -Immigration and emigration are relatively even -The number of resources and predators keep the population at a constant level -The growth ceases and everything levels off
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Limits to Population Increase Fewer resources such The Number of as food, water, and Diseases Increase: shelter: Disease spreads quickly through
The Number of Predators Increase: As predators increase in number, their
When a population gets large enough,
heavily populated areas, killing a
prey, of course, decreases from
competition increases to the point
larger number of a species than can
hunting.
where there are not enough resources
be produced.
to support a population.
The End