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 numbers declined by 90%

9. Limiting Factor #2 Food 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

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