Ecosystems & Communities Chapter 4 Ecosystems & Communities

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 23.5° South latitudes)

Heat Transport winds and ocean currents

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

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

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

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

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

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

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

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

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

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

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

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

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