BIOME: A veey Large, land ecosystem that contains several smaller, related ecosystems Biomes are distinguished by the precence of characteristic Species Interactions: -a.k.a. Symbioses or Symbiotic relationships -There are 5 different types that occur within communities (all of the organisims in an area) 1) Predation A relationship in which one organism (preditor) captures, kills, and consumes another (pray) -Natural Selection and adaptation play a big role in this relationship -preditors adapt to become better at capturing thier prey, but this puts more stress on the prey to be able to be more agile/fast to elvolve to where thier not cuaght. Predation (continued) OFFENSES: -spider webs -Flesh-tearing teeth -Snake venom DEFENSES: -Mimicry: when a harmless species resembles a poisonous or distasteful speicies; when two or more dangerous or distasteful species look alike. -Also... -Thorns on roses -Pioson Ivy reflective and -Irritating chemicals (secondary compounds) EXAMPLE: poison Ivy 2)Parasitism -Relationship in which one organism is harmed while the other benifits -Parasite feeds on the host -Does NOT usually result in immediate death for host Ectoparasites: -Live on host but do not enter the body (ticks, fleas, lice) Endoparisites: -Live inside host (disease-cuasing bacteria, tapeworms) 3)Competition -intraspecific (own species) -interspecific (other species The reason why two species would compete would be that their niches overlap/ (thier dutiy/role in the ecosystem/environment) -Competitive exclusion: one species is eliminated form a community becuase of competition for a limited recource -This is NOT he only outcome of competitiion! -Natural Selection, favoring the differences between potential competitors, may produce caracter displacement (think finches!) 4)Recource partitioning: species in competition coexist...(sharing?) Mutualism: -Relationship in which both species derive some benefit EXAMPLE: -Pollinators- *Plant provides food *Pollonator aids in plant reproduction 5)Commensalism -Relationship in which one species benifits and the other is uneffected EXAMPLES: Epiphytes- *Plants that grow attatched to other plants -Birds living in holes in trees -Sometimes re-defined as mutualism after a second benifit is discovered Amensalism: where one species is hurt and the other is uneffected Ecological Succsession: Gradual, sequental re-growth of species in an area -Where can you see it? -Abandoned fields,vacant lots -sidewalks, cracks in the concrete PRIMARY SUCCSESSION: -Development of a community in an area that has not prevously supported life -Bare rock, sand dunes, islands formed by volcanic eruption, glacier retreating -Slower (becuase soil layer must be established) Lichen-decayed lichen-soil-grass-shrubs-trees SECONDARY SUCCESION -Re-establishment of life following the disruption of an existing comminity -Forest fire, farming, logging, etc -More rapid (becuase soil is intact) Pioneer species- -Predominant early in succsession -Small, fast growing,fast-reproducing -crabgrass,ragweed,lichen -Succsession proceeds through several predictable stages until a stable point (climax community) is reached -Many succsession pathways may be possible in a particular area Ecosystem Cycles: -Water,minerals, and nutrients are always ruesed/recycled in an ecosystem -They travel through BIOCHEMICAL CYCLES WATER CYCLE -H20 is a finite recources -Cells contian 70-90% WATER CYCLE (continued) EVAPORATION- -Adds water vapor to the atmospher -Heat changes liqiud H20 into gas (vapor) TRANSPERATION: -H20 taken in by plant roots is released through stomata (as CO2 enters) PRECIPITATION: -Atmosphere becoems saturated with water vapor -Rain,sheet,hail,snow, or fog results NITROGEN CYCLE -Nitrogen Gas (N2) makes up - 78% of the atmosphere -However, this form (N2) cannot be used by organisms -Bacteria "fix" nitrogen gas-turn it into ammonia (NH3) Plants can then take up the NH3 produced by bacteria Animals get thier nitrogen by consuming plants or other animals Animals may release the nitrogen through waste and death/decay