1. Ecosystems & Communities
Chapter 4
Ecosystems
&
Communities

2. 4–1 The Role of Climate (87-89 interactive) & 4-2 What Shapes an Ecosystem (90-97 interactive)

3. Climate vs. Weather
Weather: Day to Day conditions at a particular place and time
Climate: Average yearly conditions
Temperature & Precipitations
Determined by latitude, wind & ocean currents, elevation, shape of landmass

4. Greenhouse Effect
Goldilocks zone: CO2, methane, water vapor, and other atmospheric gases trap solar energy and maintain Earth’s temp. range

6. Effect of Latitude on Climate
Earth’s tilt causes unequal heating of the earth based on latitude
Three main climate zones
Polar: ° lat.
Temperate: ° lat.
Tropical: °lat.

9. Heat Transport in the biosphere is caused by unequal heating of the earth
Creates winds and ocean currents

10. What Shapes an Ecosystem?
Biotic & abiotic factors
Habitat = the area where an organism lives
Niche = physical and biological conditions in which an organism lives and the way in which it uses those conditions

11. No two species can share the same niche in the same habitat

12. Community Interactions
Competition = organisms attempting to use a resource in the same place at the same time
Resource = any necessity of life (water, nutrients, light, food, or space)
competitive exclusion principle = rule that says no 2 species can occupy the same niche at the same time

15. Predation = interaction in which one organism captures (kills) and feeds on another organism 
Predator / Prey

16. Symbiosis = Any relationship in which two species live closely together
mutualism
commensalism
parasitism

17. Mutualism = symbiotic relationship in which both species benefit from the relationship

19. Commensalism = symbiotic relationship in which one member of the association benefits and the other is neither helped nor harmed

21. Parasitism = symbiotic relationship in which one organism lives in or on another organism (the host) and consequently harms it
Host / parasite

24. Ecological Succession
Ecosystems are constantly changing as a result of natural disturbances and human interference
Ecological succession = gradual change in living communities that follows a disturbance

25. Primary Succession 
primary succession = succession that occurs on surfaces where no soil exists
Volcano
Glacier

26. pioneer species = first species to populate an area during primary succession
Often lichens

27. Secondary Succession 
secondary succession = succession following a disturbance that destroys a community without destroying the soil
land cleared and plowed for farming is abandoned
Wildfires

28. climax community = mature, stable community that did not undergo further succession
Old growth forests