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19.2: Population Growth

19.2: Population Growth. 1. Models of Growth. Exponential birth and death rates are constant ( b > d ). 1. Models of Growth. Exponential birth and death rates are constant ( b > d ) the rate increases as the population gets larger limited by density-independent factors.

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19.2: Population Growth

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  1. 19.2: Population Growth

  2. 1. Models of Growth • Exponential • birth and death rates are constant (b > d)

  3. 1. Models of Growth • Exponential • birth and death rates are constant (b > d) • the rate increases as the population gets larger • limited by density-independent factors

  4. Draw this graph and a line showing what a logistic growth would look like

  5. works well for bacteria growth but not for most organisms

  6. 1. Models of Growth • Logistic • starts off as b> d • levels off as it reaches carrying capacity (K)

  7. 1. Models of Growth • Logistic • starts off as b> d • levels off as it reaches carrying capacity (K) • (K): the number of individuals the environment can support over time.

  8. 1. Models of Growth • Logistic • starts off as b> d • levels off as it reaches carrying capacity (K) • (K): the number of individuals the environment can support over time. • This is when b rates = d rates (zero population growth) • limited by density-dependent factors

  9. Draw this graph and a line showing what a logistic growth would look like Label carrying capacity with a K

  10. Most organisms such as seals, and whales follow this model

  11. 2. Regulating Population Growth • Limiting factors: restrains population growth

  12. 2. Regulating Population Growth • Limiting factors: restrains population growth • Density-independent factors: no regard for population density EX. Weather, seasons, natural disasters

  13. 2. Regulating Population Growth • Density-dependent factors: increase or become more prominent when the population density increases EX. predation, pollution, food shortage

  14. 3. Growth Rate • Growth rate= births – deaths per capita

  15. Growth Rate Practice 37 births/300 mice on one month; 20 deaths/ 300 mice per month.

  16. Growth Rate Practice 37 births/300 mice on one month; 20 deaths/ 300 mice per month. Growth rate = 37-20 = .057 per month 300

  17. Growth Rate Practice 100 deaths and 1000 births in a cricket population of 2,000 in 6 months.

  18. Growth Rate Practice 100 deaths and 1000 births in a cricket population of 2,000 in 6 months. Growth rate = 1000 -100 = .45 every six months 2000

  19. Growth Rate Practice 25 births/200 guppies in one week; 75 deaths/ 200 guppies per week.

  20. Growth Rate Practice 25 births/200 guppies in one week; 75 deaths/ 200 guppies per week. Growth Rate= 25-75 = -.25 per week 200

  21. Class Work • Oceanic Bacteria Lab

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