Lecture 10

Lecture 10 - Lecture 10 2/5/2008 9:06:00 AM Used to be...

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Lecture 10 05/02/2008 09:06:00 Used to be believed that annelids and arthropods were closely related-sister  classes because of the segmentation Now, annelids are more similar to mollusks (based on DNA and larvae stage) It is believed then that segmentation arised later Lophotrochozoas  Ecdysozoa 9000 species of annelids, they are terrestrial, marine, freshwater to limited  degree They can be predators, filter feeders, parasites, deposit feeders (sediments) Phylum Annelida Segmented worms Length ranges from 1mm to 3 m (giant earthworms) Major classes: polychaeta Metamerism: linear repetition of similar body segments (metameres) Unspecialized segmentation: observed externally and internally (nerves,  blood vessels, excretory organs) Value of metamerism is controlled body movement o Muscles in separate segments can act upon separate compartments of 
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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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Lecture 10 - Lecture 10 2/5/2008 9:06:00 AM Used to be...

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