1. Ecosystems & Communities
Chapter 4
Ecosystems
&
Communities

2. 4–1 The Role of Climate Words you need to know: Weather Climate
The Greenhouse Effect
Climate Zones 
polar zones (66.5° and 90° North and South latitudes)
temperate zones (between the polar
zones and the tropics)
tropical zone (23.5° North and ° South latitudes)

4. Heat Transport
winds and ocean currents

5. 4–2 What Shapes an Ecosystem?
Biotic & abiotic factors
Habitat = the area where an organism lives (biotic and abiotic factors that affect it)
Niche = full range of physical and biological conditions in which an organism lives and the way in which the organism uses those conditions

6. no two species can share the same niche in the same habitat

7. Community Interactions
Competition = organisms of the same or different species attempt to use an ecological resource in the same place at the same time
Resource = any necessity of life (water, nutrients, light, food, or space)
competitive exclusion principle = ecological rule that states that no two species can occupy the same exact niche in the same habitat at the same time

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

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

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

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

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

19. Ecological Succession
Ecosystems are constantly changing in response to natural and human disturbances.
ecological succession = gradual change in living communities that follows a disturbance

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

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

22. 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

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