1. Ecology
Biology

2. What happens to a community when a lot of people move in at one time?
Populations
What happens to a community when a lot of people move in at one time?

3. What happens to a community when a lot of people move out at one time?
Populations
What happens to a community when a lot of people move out at one time?

4. Community Interactions
Interactions between organisms in a community have a huge impact on ecosystems.

6. Symbiosis —a relationship in which two species live closely together.
More interactions
Symbiosis —a relationship in which two species live closely together.
Usually one species lives on or inside of another.
One species always benefits and other can be harmed, helped, or have no effect.

7. Mutualism —a symbiotic relationship in which both species benefit.
Types of Symbiosis
Mutualism —a symbiotic relationship in which both species benefit.
Ex: Flowers and the insects that pollinate them.

9. Ex: barnacles on a whale
Types of Symbiosis
Commensalism —a symbiotic relationship in which one species benefits and the other is unaffected.
Ex: barnacles on a whale

11. Ex: Fleas, ticks, tapeworms and their hosts.
Types of Symbiosis
Parasitism —a symbiotic relationship where one species benefits and the other is harmed.
Ex: Fleas, ticks, tapeworms and their hosts.

13. Ecological Succession
Ecological Succession —The series of predictable changes that occurs in a community over time.
As an ecosystem changes, older species gradually die out and new species move in.

14. Types of Succession
Primary Succession —When succession occurs on surfaces where no soil exists.
Ex: after a volcanic eruption builds a new island or covers land with lava rock.

15. Types of Succession
Image of Primary Succession

16. Ex: a forest after a fire.
Types of Succession
Secondary Succession —When a disturbance changes an ecosystem without removing the soil.
Ex: a forest after a fire.

17. Types of Succession
Image of Secondary Succession

18. STOP HERE

19. Population Growth
Several factors affect population size:
Births — # of organisms born
Deaths — # of organisms that die

20. Population Growth
Immigration—The movement of organisms into a population
Emigration—The movement of organisms out of a population

21. Population Growth

22. Exponential Growth
Populations with unlimited resources will continue to multiply rapidly.
J curve on graph

23. Exponential Growth Graph

24. Logistic growth
Logistic growth - occurs when a population’s growth slows and then stops following a period of exponential growth.
S curve on graph

25. Logistic growth graph

26. Carrying Capacity
Carrying capacity—The maximum number of organisms that the environment can support

27. Carrying Capacity

29. Density Dependent Factors
Density-dependent factors need large populations , or dense populations, not scattered or small ones.
Competition
Predation
Disease
Stress from overcrowding
Parasitism

30. Density Independent Factors
Density-Independent Factors affect all populations regardless of their size or density
Drought
Hurricanes
Tornadoes
Floods
Forest fires
Other natural disasters

31. Biodiversity
Biodiversity—the total variety of organisms in the biosphere.

32. Maintaining biodiversity
Humans can help maintain biodiversity by:
Enforcing the Endangered Species Act
Making laws protecting the wilderness (including rainforests)

33. Destroying Biodiversity
Humans can destroy biodiversity by:
Habitat destruction
Introducing invasive species
(ex: Zebra mussels in Great Lakes, rabbits in Australia, etc.)

34. Human activities causing global warming
Burning fossil fuels and cutting down the rainforests are increasing greenhouse gases (especially CO2), which is most likely causing global warming.