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Remember what a COMMUNITY is? How about an ECOSYSTEM ?

Behavior between species: COMMUNITIES & SPECIES INTERACTIONS. Remember what a COMMUNITY is? How about an ECOSYSTEM ?. Some common types of species interactions. Predation. Herbivory. Symbiosis. Competition. Three types of SYMBIOSIS. barnacles on whale. tapeworm. Parasitism.
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Behavior between species:COMMUNITIES & SPECIES INTERACTIONSRemember what a COMMUNITY is?How about an ECOSYSTEM?Some common types of species interactionsPredationHerbivorySymbiosisCompetitionThree types of SYMBIOSISbarnacles on whaletapewormParasitismcleanerwrasseCommensalismMutualismPlants, herbivores & predators formfood chains and "food webs"are eaten byare eaten byPRODUCERSPRIMARYCONSUMERSSECONDARYCONSUMERS(often there are more consumersabove secondary) Example of an even longer food chain:PRIMARYCONSUMERSECONDARYCONSUMERTERTIARYCONSUMERSPRODUCERSTakes a lot of producers tofeed 1 consumer... why?The 10% rule of BIOMASSFood webs can be complexconcept of "ecological niche"Because of COMPETITIONeach species has its own NICHEECOLOGICAL NICHE = the way a species "makes its living"; the "job" it hasWhat exactly does it eat? What eats it? What habitat does it need? (etc.)No two species that live in thesame area can have exactly the same ecological nicheDOMINANT speciesThe most abundant speciesOn land: usually is whichever tree/grass can out-compete the othersIn marine ecosystems: sometimes is a filter-feeder (not a plant)KEYSTONE speciesSome examples:Low abundance but has unusually big impact on the ecosystemWithout it the whole ecosystem will often "collapse"Example: marine tidepoolsMUSSELS SEA STARS "Keystone Predators" moduleThree seaweeds (algae)that photosynthesize: Three SESSILEconsumers:Three MOTILEconsumers:Nori seaweedMusselWhelk (kind of snail)Acorn BarnacleChitonsBlack pineStarfish (Pisaster)Gooseneck BarnacleCoral weedInfo from first experiment (optional)MUSSELS can out-competethe 2 barnaclesMusselAcorn BarnacleGooseneck BarnacleInfo from second experiment (optional)MusselStarfish (Pisaster)ChitonsSeaweedsWhelk (kind of snail)BarnaclesStarfish are the only predatorthat’s keeping the dominant mussels in checkMUSSELS STARFISHare eaten byMussels can out-compete all other sessile creaturesBut starfish eat musselsSTARFISH ARE KEYSTONE SPECIESKEYSTONE speciesSome examples:Low abundance but has unusually big impact on the ecosystemWithout it the whole ecosystem will often "collapse"Gray wolf: another “top predator”ELKGRAY WOLFExample: YellowstoneAfter eradication of wolf,aspen and cottonwood trees started decliningwhy?Elk eat aspen & cottonwood saplings in winter(often GIRDLE them)1995 - Wolves reintroduced to YellowstoneAnimals were wild Canada wolves (not zoo wolves)captured 1995-96Started hunting elk again......and moose...and bisonEcological effectsExpected:Elk downCottonwood & aspen upRiparian areas upUnexpected: Elk behavior also changes COYOTE DOWN RED FOX up BEAVER up, PONDS up PRONGHORN way upThe ecosystem was more complicated than we thought...... and wolves have huge effectsWolf actuallydoesn’t eatcoyote - justkills them because ofCOMPETITION
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