Lab 9: Mutualism & Nitrogen Fixation Flashcards
community
-group of 2 or more populations of different species occupying the same geographical area
intraspecific interaction
-interaction within species
interspecific interaction
-interaction btwn or among species
ectosymbiosis
-one individual lives on another organism
endosymbiosis
-one organisms lives inside of another organism
obligate symbiosis
-atleast one of the species must be in relation with the other species to survive
facultative symbiosis
-beneficial, but not necessary for survival
mutualism
-interaction btwn two organisms where both organisms benefit from the relationship in terms of increased fitness
diazotrophs
-organisms that can fix atmospheric nitrogen into a biologically usable form
how does nitrogen occur in the atmosphere?
-as a diatomic molecule (triple bonded)
why does nitrogen need to be fixed?
- aka broken into molecules which contain only a single nitrogen
- only way living organisms can use it
trophic mutualism
-both symbionts gain nutrients
defensive mutualism
-atleast one member of the mutualism is defended from predators or parasites in exchange for food (usually)
dispersal mutualism
-plants & pollinators that disperse their pollen
OR
-plants & fruit eaters that disperse the plant’s seeds
rhizoia
- anaerobic diazotroph bacteria that live in the roots of legumes (bean plants)
- legumes don’t need this if there’s another source of nitrogen (facultative)
- cannot fix nitrogen without a host plant