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Changes to Populations

Changes to Populations. 4 factors that effect the size of a population . Increase Population 1) Birth 2) Immigration (entering a population) Decrease Population 3) Death 4) Emigration (leaving a population)

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Changes to Populations

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  1. Changes to Populations

  2. 4 factors that effect the size of a population • Increase Population • 1) Birth • 2) Immigration (entering a population) • Decrease Population • 3) Death • 4) Emigration (leaving a population) • See if you can create an equation using these 4 terms for Population Growth, Population Decrease, Population Stability

  3. Is the population increasing or decreasing? • Populations Increase: • When Immigration + Births > Death + Emigration • Population Remains Stable: • When Immigration + Births = Death + Emigration: • Populations Decrease: • When Immigration + Births < Death + Emigration

  4. What are Limiting Factors? • Anything that prevents the growth of a population • What would happen without limiting factors?

  5. Carrying Capacity (k) • The maximum population a species can maintain in a certain area without damaging the ecosystem.

  6. Population can stabilize at K

  7. Limiting Factor #1: Space/Loss of Habitat • Territorial Animals need a large amount of space. • Loss of Habitat causes the decline of many species. Who took my towel?

  8. Loss of Space/Habitat Example: Bluebirds • Loss of trees/wooden posts caused a huge decline • Between 1935-1985 numbers declined by 90%

  9. Limiting Factor #2Food and Water • Leads to death via dehydration, starvation • Some animals will emigrate • Organisms that rely on one type of food are severely affected

  10. Food and Water Example: Snowshoe Hare and Lynx

  11. Limiting Factor #3: Climate and Weather • Temperature changes can affect plants and animals • Floods and storms can cause death & destruction of habitat

  12. Climate Changes Example:Mosquito Populations • Mosquitoes breed in standing water • Rainfall creates puddles of standing water

  13. Temperature Changes: Coffee Habitat Impact of Temperature Rise on Robusta Coffee in Uganda. *Developing countries, whose economies often rely heavily on one or two agricultural products, are especially vulnerable to climate change. *This graphic shows that With an increase of only 2 degrees Celsius, there would be a dramatic decrease in the amount of land suitable for growing Robusta coffee in Uganda.

  14. Limiting Factor #4:Cover • Protection from predators • Protection from weather

  15. Cover Example:Ruffed Grouse • Ruffed Grouse- Requires brushy forests for cover and food. Most of Pa’s forest were logged (cut down) 80 to 100 years ago. They grew into brushy forest allowing grouse populations to increase. Forests are now maturing reducing cover and food causing populations to decline. Land development has also reduced populations

  16. Limiting Factor #5:Increase Predation • An increase in the number of predators to an area will impact prey species.

  17. Predation Example: House Cats! • Predicted that in one year house cats kill 1 billion songbirds!

  18. Limiting Factor #6:Disease • Spread quickly through high density populations • Can devastate populations with low genetic diversity

  19. Disease: West Nile Virus • Mosquito born disease • 5,697 crows reported dead in NYS in 1999

  20. White Nose Syndrome • Fungus that has killed over one million bats • 90-100% of some species of hibernating bats are in danger of being killed.

  21. Limiting Factor #7:Light • Plants that cannot tolerate too much or too little light can be affected

  22. Light Example:Tree Growth and Shade • Aspen Pine Poplar = intolerant, will dominate young forests • Beech, Fir, Hemlock, Maple = tolerant will dominate older forests

  23. Limiting Factor #8:Human Presence • Close proximity to humans causes some species to emigrate • Other species thrive

  24. Changes in Population

  25. Competition • Limiting factors lead to competition among organisms for available resources • A loss in a limiting factor can contribute to a decline in populations • Increased due to exotic species

  26. Exotic Species- Introduced species not native or endemic to the area in question.OTHER NAMES: non-native & invasive

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