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Relationships within an Ecosystem…. NICHE. WHAT AN ORGANISM (POPULATION) DOES THE SUM TOTAL OF ALL OF THE THINGS THAT AFFECT A POPULATION THINK OF IT AS THE OCCUPATION OF THE POPULATION TWO SPECIES WITH THE SAME NICHE CANNOT SHARE THE SAME HABITAT HABITAT IS THE PLACE WHERE THEY LIVE
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NICHE • WHAT AN ORGANISM (POPULATION) DOES • THE SUM TOTAL OF ALL OF THE THINGS THAT AFFECT A POPULATION • THINK OF IT AS THE OCCUPATION OF THE POPULATION • TWO SPECIES WITH THE SAME NICHE CANNOT SHARE THE SAME HABITAT • HABITAT IS THE PLACE WHERE THEY LIVE • HUMANS AND NEANDERTHALS?
HABITAT • WHERE THE ORGANISM LIVES • THINK OF IT AS THE ADDRESS FOR THE ORGANISM • INCLUDED WITHIN THE NICHE • A COMBINATION OF PHYSICAL AND BIOLOGICAL FACTORS
SYMBIOSIS ORGANISMS LIVING TOGETHER IMPLIES SOME SORT OF TIGHT RELATIONSHIP RELATIONSHIP MAY BENEFIT ONE PARASITISM COMMENSALISM OR BOTH MUTUALISM
PARASITIC STRATEGIES • One creature benefits, and the other is harmed • Maximize host ability to support parasite • Only kill host after all resources sequestered • Good parasites don’t kill host • Parasites may evolve to become less harmful • Can you think of an example of Parasitism in your life??
MUTUALISM • Interactions where both species benefit • May evolve from parasitic situations • Part of a continuum • Mutualistic situations may become obligate • ENDOSYMBIOTIC RELATIONSHIPS PROBABLY EVOLVED VIA THIS ROUTE
Mutualism – Ant and Aphid http://www.richsoil.com/antsandaphids/ants_aphids_sugar.jpg
The Aphid and the Ant • Aphids feed on the sap of the plant they are on. • Ants use their antennae to stimulate the aphids and cause them to excrete from their abdomen a substance called honeydew which is rich in the nutrients ants require. • Each worker ant goes from aphid to aphid collecting honeydew which she stores in her abdomen until it's full; then, she returns to the nest and regurgitates to feed other members of the colony. • Ants, in return for the honeydew, protect the aphids from predators such as flies, wasps, and beetles. • The ants, like human ranchers, sometimes move their aphids to richer grazing grounds. • YUMMY!
A Little Aphid Ant Humor http://images.google.com/imgres?imgurl=http://www.ibiblio.org/Dave/Dr-Fun/inline/thumbs/tn20001013.jpg&imgrefurl=http://www.ibiblio.org/Dave/ar00295.htm&h=190&w=258&sz=20&hl=en&start=9&tbnid=5x78fixpPQkJAM:&tbnh=82&tbnw=112&prev=/images%3Fq%3Daphid%2Bant%26svnum%3D10%26hl%3Den%26lr%3D%26sa%3DN
COMMENSALISM • One benefits • The other unaffected • Can grade into parasitism • Remora on shark/whale • Can grade into mutualism • Slightly helping your commensal may be of benefit • Can you think of an example of commensalism in your life??
Cattle Egret - Commensalism The cattle stir up grasshoppers and other insects that the egret likes to eat. There is no apparent benefit to the cow. http://mishami.image.pbase.com/u43/jypsee/upload/27771434.anguswithegret.jpg
SYMBIOTIC RELATIONSHIPS FORM A CONTINUUM FROM MUTUALISM TO PARASITISM (WHICH MAY BE DIFFICULT TO DISTINGUISH FROM PREDATION)
WARNING AND MIMICRY • Predator deterrent evolves • Warning • color of bees & wasps • coral snakes • monarch butterflies • Convergence in warning – Mullerian Mimicry • Copy the warning without the deterrent Batesian Mimicry • moths & flies • king snakes • viceroy butterfly
CRYPSIS • Look like something inedible or inert • Be invisible • jellyfish • silvery fishes • Nocturnal behavior