emery_lecture_18

emery_lecture_18 - Lecture 18 I. introduction to positive...

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Lecture 18 I. introduction to positive interactions - positive interaction : interaction in which neither species is harmed and benefits outweigh costs for at least 1 species - commensalism : 1 species benefits without affecting the other (+/0) - mutualism : both partners benefit from interaction (+/+) 1. obligate: when 2 species are fully dependent on each other 2. facultative: either partner can live alone if necessary - doesn’t have to be symmetric (both species don’t have to be the same) Mutualisms 1. trophic mutualisms - farming ants (leaf cutter ants) - each species provides food to other species 2. habitat mutualism - one provides other with shelter 3. service mutualisms a) defense - acatia gives food and shelter to ants in return for defense for plant (from deer and other plants) b) dispersal - take seeds and plant them away from maternal plant because eat fruit - birds eat fruits and poop seeds which don’t break down inside c) pollination – facilitate movement of gametes to other plants
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emery_lecture_18 - Lecture 18 I. introduction to positive...

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