Chapter 32

Chapter 32 - Ingrid Shih BIO 1306-08 24 January 2011...

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BIO 1306-08 24 January 2011 Chapter 32: Protostome Animals 32.1 What is Protostome? 2 Triplolastic clades: o Protosomes o Deuterostomes Protostomes have far more species and individuals Protostomes are defined by o Blastopore forms the mouth o Bilaterally symmetrical o An anterior brain around entrance to the digestive tract o Ventral nervous system Paired/fused longitudinal nerve cords Coelom is ancestral, but some lineages have modifications: o Flatworms are acoelomate (coelom has been lost) o Some lineages of a pseudocoelom Lophotrochozoans o Lophophore, a circular or U-shaped ridge around the mouth with two rows of hollow, ciliated tentacles used for: Food collection Gas exchange o Trochopohre larval stage, moves via beating a band of cilia found lin: Bryozoans Ribbon worms Mollusks Annelids o Ecdysozoans Cuticle, secreted by the epidermis Molt New cuticle is already forming when they are preparing to mold Old cuticle is shed New expands and hardens Vulnerable during hardening Thin and flexible cuticle allows o Gas and water exchanged o Lives is moist habitats Hard and rigid o
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This note was uploaded on 03/23/2011 for the course BIO 1306 taught by Professor Adair,tamarah during the Spring '08 term at Baylor.

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Chapter 32 - Ingrid Shih BIO 1306-08 24 January 2011...

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