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)

3. Is the population increasing or decreasing?
When Immigration + Births are greater than Death + Emigration:
Populations Increase
When Immigration + Births are equal to Death + Emigration:
Population remains stable
When Immigration + Births are less than Death + Emigration:
Populations Decrease

4. Limiting Factor Something that prevents the growth of a population
What would happen without limiting factors?

6. Reflection
Think of an example where an organism does not have enough limiting factors.
What is the organism, how does this affect the habitat around that organism?

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

8. Population can stabilize at K

9. Populations can crash if #s go above K
29 introduced in 1944
More than 6,000 by 1963
Down to 42

10. Seasonal Fluctuations

11. Limiting Factor #1: Space
Territorial Animals need a large amount of space
Loss of Habitat causes the decline of many species

12. Bluebirds Loss of trees/wooden posts caused a huge decline
Between numbers declined by 90%

13. 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

14. Darwin’s Finches Drought caused a loss in seed numbers
Finch numbers declined from 1400 to 200

15. Snowshoe Hare and Lynx

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

17. Mosquito Populations Mosquitoes breed in standing water
Rainfall creates puddles of standing water
Culex tarsalis-WNV

18. 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.

19. Limiting Factor #4: Cover
Protection from predators
Protection from weather

21. Limiting Factor #5: Increase Predation
An increase in the number of predators to an area

22. House Cats!
Predicted that in one year house cats kill 1 billion songbirds!

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

24. West Nile Virus Mosquito born disease
5,697 crows reported dead in NYS in 1999

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

26. Tree Growth and Shade
Aspen Pine Poplar = intolerant, will dominate young forests
Beech, fir, hemlock, maple = tolerant will dominate older forests

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

29. 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

30. Exotic Species-Introduced species not native or endemic to the area in question (alien species).