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HUMAN POPULATION GROWTH. Key Vocabulary: -Expotential Growth -Immigration -Emmigration -Birth Rate -Death Rate. Okay…but what’s the point?. This happens in the real world too BUT on a MUCH bigger scale. http://www.census.gov/popclock/. What is a population?.
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HUMAN POPULATION GROWTH Key Vocabulary:-Expotential Growth -Immigration -Emmigration -Birth Rate -Death Rate
Okay…but what’s the point? This happens in the real world too BUT on a MUCH bigger scale. http://www.census.gov/popclock/
What is a population? Apopulationis the number of organisms of the same species living in an area.
Look at the graphs below: • In 1 complete sentence, describe what is happening in graph A. • In 1 complete sentence, describe what is happening in graph B. • Choose one of the graphs to label “S-curve”. Explain why you chose this graph. • Choose on of the graphs to label “J-curve”. Explain why you chose this graph.
Exponential growth = the J curve • Grows at a fast increasing rate with NO limiting factors What are the types of population growth?
Logistic Growth =S Curve • Levels off due to limiting factors • Reaches carrying capacity (largest # of organisms the ecosystem can support) What are the types of population growth?
Currently growing: Exponentially(J curve) but we can’t do that forever! • We underwent a demographic transition:throughout history we’ve had high birthrates and high death rates, so populations remained stable. • With advances in medicine, nutrition, and sanitation, we now havelow death rates so the world population is increasing rapidly. How is the human population growing currently?
What is a limiting factor? Limiting factors are factors that prevent a population from growing infinitely (forever!) Examples:
4. Disease Bark Beetle
5.Shelter/Habitat ? NOPE! Not the right Habitat (Home)
What factors affect population size? The Birth Rate is the number of babies being born per unit time
What factors affect population size? The Death Rate (mortality) is the number of individuals that die per unit time
Immigration is the number of individuals that move INTO a population Emigration is the number of individuals that exit (leave) a population What factors affect population size?
(Births + Immigrants) - (Deaths + Emigrants) Leads to Population Decline Leads to Population Growth