Ecosystems and Communities Interdependence in Nature Chapter 4

Climate  Weather vs. climate –Both measure of temperature and precipitation  Day-to-day = weather  Average conditions over long period = climate  Climate is NOT uniform within a region –Microclimates – important to many organisms but not necessarily readily noticeable

Factors that Affect Climate  Solar energy –Greenhouse effect – certain gases allow light to enter atmosphere but trap heat  Latitude –Amount of direct sunlight received decreases as we move from equator to poles –Causes tropical, temperate and polar regions  Transport of heat –Wind  warm air rises, cold air sinks –Ocean currents

Niches  Tolerance – the ability to survive and reproduce under a range of environmental conditions –Every organism has an upper and lower limit –Helps determine habitat – the general place where an organism lives (the “address”)  Niche – the “job” of the organism (both where and how) –Resources – any necessity of life –Contains both biotic and abiotic factors

Competition  Occurs when organisms attempt to use the same limited resources –Both among species (intraspecific) and, –Between different species (interspecific)  Competitive exclusion principle – no two species can occupy exactly the same niche

Predation, Herbivory, and Keystone Species  Predation – predator captures and feeds on prey  Herbivory – herbivore feeds on producers (plants)  Keystone species – single species that can cause dramatic changes in the community based on presence or absence

Symbioses  Relationship where two species live closely together  Three major types –Mutualism – everybody wins (both organisms benefit from interaction) –Parasitism – I win, you lose (harm or death) –Commensalism – I win, you get nothing and like it! (no harm or help)

Succession  Ecological succession – series of changes that occur in a community over time  Primary vs. Secondary –Primary – an area where no community remains (a clean start)  Pioneer species – first to colonize a barren area –Secondary – an area where disturbance has occurred (fire or disaster)