Lecture 21

Lecture 21 - Lecture 21 (Tomorrow is 41st earth day )...

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Lecture 21 (Tomorrow is 41 st earth day ) Mutualism and Symbiosis —different species can co-evolve to collaborate for mutual gain. (mutualism and cooperation (+ +)) Mutualism- association between 2 species that confers mutual fitness benefits for both species o Were long thought to be oddities but recently its been recognized that they are widespread and important o Dan Janzen argued that they are widespread and important Recognized 5 types of mutualism Harvest mutualism Pollination mutualisms Seed dispersal mutualism Protective mutualism Human agriculture /animal husbandry o Clown fish living in sea anemone = mutualism (clown fish lives in anemone without get stung and anemone gets the food scraps from the fish>>+ +) Facultative mutualism o Not an obligate relationship interacting species all benefit o may involve multiple species o may be condition dependent o coevolution not extreme Obligate mutualism o An obligate relationship o Both species benefit o Involves one pair of species o Not condition dependent o High level of coevolution Cellular endosymbiosis o Mitochondria—aerobic repistration o Chlorplast—photosynthesis o Dinoflagellate endosymbionts of the genus Symbiodinum, commonly known as zooxanthellae, are found in corals, mollusks, sponges, an foraminifera o These endosymbionts drive the amazing formation of coral reefs by capturing sunlight and providing their hosts Primary endosymbionts o Associated with their hosts for man millions of years, they form obligate associations, live in specialized organs (ex. Bacteriocytes) o <slide> Secondary endosymbionts o More recent association horizontally transferred between hosts, live in the haemolmph of the insects, are not obligate
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o Pea aphid is known to contain at least 3 secondary endosymbionts Harvesting symbiosis example! o
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This note was uploaded on 01/23/2012 for the course BIO 106 taught by Professor Jeffreyjensen during the Fall '10 term at NYU.

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Lecture 21 - Lecture 21 (Tomorrow is 41st earth day )...

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