BIO220H1 Chapter Notes - Chapter 2: Organelle, Coevolution, Medicago
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BIO220H1 Full Course Notes
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Mutualism: ants protect acacia plants from herbivory / acacia shelters + feeds ants. Has costs for both species: plant use resource to provide food + shelter for ants, ants risk predation by protecting plant. Benefits outweigh costs for both, interaction is advantageous. Mutualism: interaction btwn 2 species where both benefit. Mutualism stable as long as both species benefit from interaction. If costs low relative to benefits, exploiters don"t have big effect. = stability of mutualism <><> balance of costs + benefits on interaction. Lab: study mutualism btwn legumes + soil bacteria (rhizobia, legumes make nodules in roots, nodules infected by bacteria that make atm. N2 into ammonia (nh3: plant gives rhizobia carbon, some rhizobia exploit by not fixing nitrogen. Medicago lupulina black meddick : annual (sometimes biennial/perennial) legume, found on roadside, field, pastures, disturbed habitats, easily outcompeted by other plants. Which why grows in marginal n-limited soil: mutualism w/ rhizobia typically in any bacteria in ensifer genus.
