Lecture14

Lecture14 - 14/02/2008 09:07:00 Echinodermata Means spiny...

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Unformatted text preview: 14/02/2008 09:07:00 Echinodermata Means spiny skin Only major invertebrate deuterostome phylum 7000 species Exclusively marine, benthic o Didnt make it in freshwater or on land Radial symmetry o Penta-radial o Secondarily derived-their larvae are bilateral Endoskeleton: calcareous plates covered by skin Class Asteroidea Sea stars or sea fish 5 or more radial arms all marine habitats (intertidal or deep sea) Mostly carnivorous They have tube feet o Water comes in through madreporite, passes through stone canal then the ring canal (only central structure) o Ampullae are like little squeeze bulbs, when contracted they cause the two feet to extend and stick onto things with suckers They exude their stomachs out of their mouths and onto their prey, stomach excretes digestive enzymes and suck up the nutrients, they pull the stomach...
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This note was uploaded on 04/26/2008 for the course BIOL 305 taught by Professor Green during the Spring '08 term at McGill.

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Lecture14 - 14/02/2008 09:07:00 Echinodermata Means spiny...

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