Class Notes (836,370)
Canada (509,757)
York University (35,328)
Biology (2,253)
BIOL 2030 (120)
Lecture

Mollusca

5 Pages
108 Views
Unlock Document

Department
Biology
Course
BIOL 2030
Professor
Scott Kelly
Semester
Fall

Description
Mollusca Mollusca Large and diverse phylum of soft-bodied, usually unsegmented, coelomate animals, many of which live enclosed in a ahrd shell. They include the classes Gastropoda (e.g. winkles, whelks, slugs, nails, se slugs), Bivalvia (e.g. clams, cockles), and other smaller classes of shells, and the the Cephalopoda (nautilus, squids, and octopuses). The coelom is small and the main body cavity is a blood-filled haemocoel. Molluscs have a heart and blood system, and well-developed sense organs and nervous system, esp. in the Cephalopoda Matle Fold of soft tissue underlying shell in molluscs, barnacles and brachiopods, and which usually encloses a space, the matle cavity, between it and the body proper Radula Short, broad organ with rows of chitonous teeth in mouth of most gastropod molluscs Visceral mass Ctenidia A comblike structure, such as the respiratory apparatus of a mollusc Pallial groove Pallial = “having a mantle” Nephridiopore External opening of excretory organs (nephridia) in invertebrates Siphon Of aquatic molluscs, funnel-shaped structure from mantle cavity to exterior, through wich water is drawn in and out, and which in some molluscs can be used as a means of jet propulsion Odontophore The tooth-bearing organ in molluscs Gonochoristic Species having sex chromosomally determined as either female or male Ovotestis The reproductive organ of naturally hermaphrodite animals, which produces both eggs and sperm Trochophore Free-swimming top-shaped pelagic larval stage of annelids, bryozoans, and some molluscs, forming part of the zooplankton. It has a ring of cilia around the rim and a terminal ring or tuft of cilia in front of the mouth Planktotrophic Feeding trochophores on plankton (catch small plankton in prototroch) Lecithotrophic Non-feeding trochophores which use large yolk reserves, short planktonic lives Veliger larva Second larval stage in some molluscs, developing from the trochophore Velum Membrane or structure similar to a veil Glochidium larva The parasitic larva of freshwater mussels such as Unio and Anodon Ovisac Egg case or receptable Prototroch Preoral circlet of cilia of a trochosphere larva Haemocoel Blood-filled cavity constiting of spaces between organs, which is the main body cavity in molluscs Mollusca - most aquatic, very diverse, coelomate (triploblastic) >93K spp Characteristically diverse, 1mm – 18m in size, various speed (mmt), herbivores/detrivores/filter- feeders/predators; 7km above sea level to anywhere deep  Gastopoda[most], Bivalvia [21.5%], Cephalopoda [1], Polyplacophora [1], Scaphopoda [1], Aplacophora [0.4], Monoplacophora [0.03] **Life Tree** SQUID: on dorsal side, an internalized shell which facilitates open-water mmt; Octopus – shell completely lost (hence ‘reduced’ on chart)  Mantle specialized tissue formed by dorsal epithelium; secretes shell (s)  Radula tongue-like organ with teeth used for feeding (not in bivalvia)  “Foot” ventral body wall muscles developed for locomotion/clinging [head-foot] HAM – Hypothetical Ancestral Mollusc Typical mollusc 1. Foot/head-foot 2. Visceral Mass includes gonads, etc. (digestive/circulatory/excretory) 3. Shell 4. Mantle Overhangs “mantle cavity”  protective gills area Ctenidia respiratory organ: ciliated molluscan gills housed in mantle cavity
More Less

Related notes for BIOL 2030

Log In


OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit