Power8_FoodWebsChains - Mutualism leaf cutter ants(Atta spp...

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1 Mutualism (+,+) leaf cutter ants (Atta spp ) culture fungi (Ignacio Chapela, ESPM) Mark Moffett photos 2 Minors defend workers from parasitic phorid flies Herbivory/fungivory: leaf cutter ants 3 Fungal garden in underground chamber of ant colony Young queen carries bit of fungus to start new colony 4 Mutualisms (+,+) 5 Extrafloral nectaries on Acacia feed ants that protect the Acacia trees from herbivores and vines 6 Clown fish live in mutualistic symbiosis with sea anemone • Clown fish mucus protects it from anemone sting, and clown fish feeding imports crumbs that feed anemone
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7 3 species interactions: Mutualists and cheaters…. Cleaner wrasses, host fish, cheater blennies Milkweed, bee, cheater orchid Pollinator, moth, bumblebee nectar burglar Selection for refinement of cues and mimicry in co-evolutionary race How much cheating can be tolerated before mutualism breaks down? 8 Taxon 2 species Lump all organisms into ‘trophic levels’ Focus on particular species whose strong interactions limit important populations 9 Community : a group of species that co-occur in time and space Food (interaction) webs depict feeding (or other significant (e.g. population limiting or regulating)) relationships among members of a community Interaction webs, food webs, food chains Some of these interactions are strong, others are weak. System : group of entities united by interaction or interdependence to form or act as an entire unit How to simplify for study? 10 Sometimes strong effects are mediated through food chains. Hairston, Slobodkin and Smith (1960): “The world is green because predators hold herbivores in check.” (assumes a 3 level food chain) + + + - - 11 Fretwell (Kansas) : world might have more or fewer than 3 trophic levels: Odd numbers ! Green Even numbers
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This note was uploaded on 04/01/2008 for the course BIO 1B taught by Professor Carlson,mischel,power during the Fall '07 term at Berkeley.

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Power8_FoodWebsChains - Mutualism leaf cutter ants(Atta spp...

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