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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