Test 3 Study Guide

Test 3 Study Guide - Test 3 Study Guide I. Phylum Mollusca...

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I. Phylum Mollusca General characteristics: Head, tentacles, eyes Foot – ventral muscles Mantle Shell (absent in aplacophora) Dorsal visceral mass Mantle cavity Mouth, jaws, radula; complete digestive system Nervous system - ventral Circulatory system: o 3 chambered heart o Blood sinuses o Some have open or closed system o Blue blood – hemocyan Excretory system Reproductive system Ancestral group: Aplacophora Group that developed from aplacophora to have shell: monoplacophora Genus name of living monoplacophirid: Neooilina Life style - bottom crawlers No siphuncle – except cephlopoda Class name of chitins (8 plates) – polyplacophora Characteristics of Rostroconchia that make it different from monoplacophora Most have 1 shell, 1 piece mantle Lost their head and sealed off shell along part of margin Mantle and shell extended ventrally Laterally compress body Reorientation to detritus feeding life style o Anterior foot o Incurrent and excurrent posterior siphons, some forms filter feed Growth requires breaking, resorption and resealing Which classes did Rostros give rise to - bivalvia and scaphopoda Tusk shells – scaphopods Geological range of scaphopods – ordovician to recent Geological range of aplacophora – precambrian All other – cambrian Gastropods major mode of life – crawling Cephalopods – swim using water jet propulsion Bivalves and rostroconchs – burrowing lifestyle Evolutionary trends to develop gastropods Coiling to lower center of gravity Helps crawling Twisted digestive system
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This note was uploaded on 04/29/2008 for the course BIO 3435 taught by Professor Bonem during the Spring '08 term at Baylor.

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Test 3 Study Guide - Test 3 Study Guide I. Phylum Mollusca...

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