Transcript Lecture 9
MARE 171 Marine Biology: Diversity Dr. Turner Fall 2014 Higher Invertebrates Higher Invertebrates Molluscs: animals that belong to the phylum Mollusca; one of the largest most successful groups of animals (chitons, snails, clams, octopods, squid) Higher Invertebrates Head-Foot: the part of the molluscan body that contains the animal’s head and a muscular foot Visceral Mass: the part of the molluscan body that contains all of the organs, with the exception of the animal’s head and foot Higher Invertebrates Mantle: a tissue found in molluscs that is responsible for forming the shell in animals that have one and that in cephalopods functions in locomotion Mantle Cavity: the space between the mantle and the mollusc’s body Higher Invertebrates Radula: a ribbon of tissue that contains teeth; present in all molluscs except bivalves Higher Invertebrates Periostracum: the outermost layer of a molluscan shell Conchiolin: a protein that makes up the periostracum Prismatic Layer: the middle layer of the molluscan shell and is composed of CaCO3 and protein Higher Invertebrates Chitons: are members of the molluscan class Polyplacophora and they have flattened bodies that are most often covered by eight shell plates - herbivores; feed with radula Higher Invertebrates Scaphopods: are members of the molluscan class Scaphopoda commonly called tusk shells - buried in sediment; feed with tentacles Higher Invertebrates Gastropods: are members of the molluscan class Gastropoda - most shelled; single piece called Univalve - (a) Coiled or (b) Uncoiled Higher Invertebrates Whorl: a turn of a gastropod shell around a central axis Aperture: the opening to a gastropod shell Operculum: a structure that some gastropods have for closing their aperture Higher Invertebrates Gastropod Feeding Strategies Herbivorous Grazer Filter Feeders Carnivorous Predator Higher Invertebrates Gastropod Feeding Strategies Bulb Gland: gland located near the mouth of cone snails that produces the venom that coats the snail’s radula Carnivorous Predator Higher Invertebrates Naked Gastropods Nudibranchs: are marine gastopods that lack a shell; Cerata: projections found on the body of nudibranchs that increase the surface area available for gas exchange Higher Invertebrates Gastropod Reproduction Internal fertilization in most species; eggs laid in projective jelly-like substance - some external fertilization Primitive gastropods Trochophore larvae: a free swimming larval stage associated with primitive gastropods that shed their eggs into the water Higher Invertebrates Trochophore Larvae: a free swimming larval stage associated with primitive gastropods that shed their eggs into the water Veliger Larvae: a freeswimming larva stage characteristic of many marine gastropods Higher Invertebrates Hermaphroditic Limpets – Credipula Congregate in stacked groups; male on top fertilizing eggs of female below All start at males; change to female depending upon sex ratios – determined by Phermones: a hormone released into the environment by an animal, FIG 9-11 that controls the development and behavior of other animals of the same species Higher Invertebrates Bivalves: are molluscs in the class Bivalvia that have two hinged shells (Valves) covering their body - Have no head or radula; bodies are laterally compressed; shell hinged by ligaments FIG 9-12 Higher Invertebrates Bivalve Anatomy Umbo: the area around the hinge and the oldest part of a bivalve shell; grows outward Adductor muscles: close the two valves of a bivalve shell Higher Invertebrates Bivalve Anatomy Inhalant opening: an opening formed by the mantle that allows water to enter the mantle cavity Exhalant opening: an opening formed by the mantle that allows water to exit the mantle cavity Higher Invertebrates Bivalve Anatomy Inhalant opening: an opening formed by the mantle that allows water to enter the mantle cavity Exhalant opening: an opening formed by the mantle that allows water to exit the mantle cavity Palps: are a pair of structures, located near a bivalve’s mouth, that form a food mass from the food filtered by the bivalve and move it to the animal’s mouth Higher Invertebrates Bivalve Adaptations Soft-Bottom Burrowers, Attached surface dwellers, Figs of each organism Higher Invertebrates Bivalve Adaptations Unattached surface dwellers, Boring Bivalves Figs of each organism Higher Invertebrates Cephalopods: are members of the molluscan class Cephalopoda, which includes octopods and squid Two major types: Nautiloids: cephalopods whose body is covered by a shell Coleoids: cephalopods that do not have an external shell Higher Invertebrates Nautiloids – produce large coiled shells composed of chambers Septa: partitions that separate the chambers of a nautilus shell Higher Invertebrates Siphuncle: a cord of tissue that runs through the chambers of a nautilus shell and removes seawater from new chambers as they form Crop: a sac-like structure that stores food Higher Invertebrates Coleoids – have 10 appendages; 8 arms and 2 tentacles; have small internal shells Squid have a Pen: a strip of hard protein that helps support the mantle Higher Invertebrates Sepia: a dark fluid produced by the ink gland of coleids; contains Melanin: a brown-black pigment; Deep-sea squid have white or bioluminescent Sepia Chromatophores: are pigment containing cells that function in color changes Higher Invertebrates Spermatophore: a package of sperm Oviduct: a tube that carries eggs to the outside of the body Higher Invertebrates Annelids: worms belonging to Phylum Annelida; bodies are divided internally and eternally into segments Many have a Hydrostatic Skeleton: a means of supporting an animal’s body using fluid contained in a body compartment Setae: small bristles on the skin of some annelids Higher Invertebrates Polychaetes: annelid worms belonging to the class polychaeta