POPULATIONS :POPULATIONS 1 M.BREGAR (Dante C.S.S.)


What is “Population Size”? :What is “Population Size”? Total number of 1 species in an ecosystem. You can select the ecosystem Example: Population of people in Dante Population of people in Toronto 2 M.BREGAR (Dante C.S.S.)


What is a Population? :What is a Population? An ecosystem is made of several populations: Imagine High Park: 3 M.BREGAR (Dante C.S.S.)


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Populations :Populations M.BREGAR (Dante C.S.S.) 5


Population Growth :Population Growth The rate at which a population size changes. Populations can increases or decrease, but most populations remain stable 6 M.BREGAR (Dante C.S.S.)


World Population Growth :World Population Growth 7 M.BREGAR (Dante C.S.S.)


Factors Controlling Population Growth :Factors Controlling Population Growth Natality Number of births Immigration Individuals entering an ecosystem Mortality Number of deaths from diseases, being eaten, etc. Emigration Individuals leaving an ecosystem Population Increases Population Decreases 8 M.BREGAR (Dante C.S.S.)


Factors Controlling Population Growth :Factors Controlling Population Growth M.BREGAR (Dante C.S.S.) 9


Factors Controlling Population Growth :Factors Controlling Population Growth To measure if how a population grows, we calculate population growth using the following formula: POPULATIONGROWTH = (NATALITY + IMMIGRATION) – (MORTALITY + EMIGRATION) Population Increases Population Decreases 10 M.BREGAR (Dante C.S.S.)


Closed Population :Closed Population These are populations in which individuals can NOT enter (immigration) or leave (emigration) Populations change because of births and deaths. Example – Zoo or Fishtank 11 M.BREGAR (Dante C.S.S.)


Open Populations :Open Populations These are populations affected by all four factors (birth, death, immigration, and emmigration) Example – natural ecosystem, park 12 M.BREGAR (Dante C.S.S.)


Population Histograms :Population Histograms These provide information about the number of people at different ages Allow us to decide if a population is growing, stable, or on the decline. 13 M.BREGAR (Dante C.S.S.)


Population Histograms :Population Histograms Growing Populations More individuals at younger ages Shaped like a pyramid, with a wide base 14 M.BREGAR (Dante C.S.S.)


Population Histograms :Population Histograms Stable Populations About the same number of individuals at every age Straight shaped 15 M.BREGAR (Dante C.S.S.)


Population Histograms :Population Histograms Declining Populations Wider portions found toward the middle of the population Smaller base 16 M.BREGAR (Dante C.S.S.)


J-Curve :J-Curve A population with unlimited resources grows in the form of a J-Curve In the natural world, J-Curve does not occur because resources are LIMITED 17 M.BREGAR (Dante C.S.S.)


Human Population Growth :Human Population Growth M.BREGAR (Dante C.S.S.) 18