Topics 9-11 Flashcards
unusual ribbon of teeth for feeding present in phylum mollusca
radula
what is the purpose of the mantle in phylum mollusca?
respiration and shell secretion
the ancestral traits of this phylum include:
-radula (ribbon of teeth)
-large muscular foot or tentacles for movement
-mantle for respiration and shell secretion
mollusca
in phylum mollusca, the head-foot contains which three organ types?
feeding
sensory
locomotory
which structure is unique to molluscs?
radula
in phylum mollusca, these complex muscles move radula and its supportive cartilages in and out of the mouth
odontophores
in phylum mollusca, this structure is usually ventral and used as attachment to substratum for locomotion
muscular foot
in phylum mollusca, this structure is a sheath tissue on each side of the body that protects the soft parts and forms the space called the mantle cavity
mantle
in phylum mollusca, this structure houses the gills or lungs that develop from the mantle and the exposed surface used in gas exchange; products of digestive, excretory, and reproductive systems empty into it
mantle cavity
in phylum mollusca, this class uses the head and mantle cavity to create jet propulsion
cephalopods
in phylum mollusca, this class can withdraw the head and foot into the mantle cavity and hide into a shell
gastropods
in phylum mollusca, this structure has leaf-like filaments with cilia that propel water across the surface
mollusc gill (ctenidium); usually have two
explain the circulatory system of most organisms in the phylum mollusca
open circulatory system with blood sinuses; countercurrent blood and water movement facilitates gas exchange; usually two ctenidia are on opposite sides and form an incurrent and excurrent chamber
in the phylum mollusca, this section of the shell is the outer horny layer that is composed of conchiolin; protects against acid from leaf decay
periostracum
in the phylum mollusca, this section of the shell is densely packed prisms of calcium carbonate laid on protein matrix
middle prismatic layer
in the phylum mollusca, this section of the shell is secreted continuously by the mantle surface so it increases in thickness as the animal grows
inner nacreous layer
in the phylum mollusca, this class have a closed system with a heart, vessels, and capillaries and enable them to move actively
cephalopods
in the phylum mollusca, most are dioecious or monoecious?
dioecious; some are hermaphroditic
what kind of larva do molluscs have?
trocophore
In many gastropods and bivalves, a uniquely molluscan intermediate larval stage this structure is hatched with the beginnings of a foot, shell, and mantle
veliger
in phylum mollusca, this class is about 120 species of wormlike, marine organisms ranging from 2 to 140 mm long
caudofoveata
in phylum mollusca, this class is approximately 250 species; similar to caudofoveates, but have no radula or gills
solenogasters
in phylum mollusca, this class is generally flattened dorsoventrally with a convex dorsal surface that has 7 or 8 articulating limy plates; about 1000 currently described species that range from 2 cm to 30 cm
polyplacophora
in phylum mollusca, this class previously was considered extinct; 25 extant species now known
monoplacophora
in phylum mollusca, this class
* Most diverse class with over 70,000 living and more than 15,000 fossil species
* Range in forms like marine snails, limpets, slugs, whelks, conches, periwinkles, sea
slugs, sea hares, and sea butterflies, to air-breathing terrestrial snails and slugs
* Typically sluggish, sedentary animals dueto heavy shells used as chief defense
* Some snails are specialized for climbing, swimming, or burrowing
* Marine, freshwater and terrestrial
* Intermediate hosts
* Helix pomatia
– Escargo
gastropoda
180 degree counterclockwise twisting of visceral mass, mantle, and mantle cavity during development
torsion
in the phylum mollusca, the ____ can enhance protection and prevent desiccation during torsion
operculum
in the phylum mollusca, a flattened foot, cilia propelling over mucous trails, and musclar waves are responsible for what?
locomotion
what kind of shell in molluscs?
-more compact, but unbalanced
-shell shifted over body for better weight distribution
-internal organs asymmetrical and sometimes no longer paired
conspiral shell
what kind of shell in molluscs?
-earliest fossils, one plane (flat)
planospiral shell
what phylum has these digestive traits?
-Most scrape algae and attached organisms
– Herbivores, predators, scavengers
– Digestive tract
* Extensible proboscis (with radula)
* Some are ciliated feeders
* Food incorporated into mucous mass
molluscs
what species of snails feed on fish, worms, and molluscs using a lethal sting to secure prey?
conus
in the phylum mollusc, what is the name of the venom from a modified radula forming a harpoon with poison glands
conotoxin
what structure do the phylum molluscs use for gas exchange?
ctendidia and siphon
in the mollusc phylum, which is the largest subclass with mostly marine species and some freshwater forms?
prosobranchia
in the mollusc phylum, which is all marine species, including sea slugs, sea hares, nudibranchs, and canoe shells?
opisthobranchia
in the mollusc phylum, which is terrestrial and freshwater species?
pulmonata
in the mollusc phylum, which class:
-clams oysters, mussels, scallops
-range in size from 1-2 mm in length to the giant South Pacific clams
-most are sedentary feeders and depend on currents produced by cilia
-lack a head, radula, cephalization
-most are marine, but some live in brackish water
class bivalvia
in the mollusc phylum, which class:
-has shell and associated structures (two hinged valves, umbo, mantle)
-pearls are produced when irritant is lodged between the shell and mantle
class bivalvia
in the mollusc phylum, which class:
-has a visceral mass, muscular foot, and ctenidia
-use gills and mantle for gas exchange
-are filter feeders
-three chamber heart
-nephridial tubules
-dioecious
-external fertilization
class bivalvia
in the mollusc phylum, which class:
-squids, octopuses, cuttlefish, and nautiluses
-marine predators
-foot modified into circle of tentacles or arms
-head in line with visceral mass
-muscular mantle
class cephalopoda
in the mollusc phylum, which class:
-shell of nautiloid and ammonoid shells with gas chambers (buoyant)
-use jet propulsion
-predators
-digestive tract with large digestive glands
class cephalopoda
in the mollusc phylum, which class:
-has a closed circulatory system
-large brain
-chemoreceptor cells in their arms
-chromatophores and ink glands
-observational learning and sophisticated communication
-dioecious
-males produce spermatophores
-juveniles hatch with no free-swimming larvae
class cephalopoda
this phylum has these ancestral traits:
-spiral cleavage, trocophore larvae
-body metameric, bilaterally symmetrical, and worm-like
-composed of segments (metameres)
-specialization of body regions (tagmatization) possible
phylum annelida
what is tagmatization?
specialization of body regions
what is a metamere?
serially repeated units or segments that are separated by partitions called septa
what phylum?
Body Plan
– Head is composed of two
parts: prostomium and
peristomium, followed by
segmented body
– Terminal portion bearing the
anus is the pygidium with
the head and pygidium not
considered metameres
– New metameres form in front
of the pygidium so the oldest
segment is in front and the
youngest at the rear
– Parapodia form flaps on
each segment
phylum annelida
what muscles do annelids use to move?
circular and longitudinal muscles
what is the digestive system of annelids like?
Digestive system is not segmented with the gut running through the whole body perforating the septa
which class?
many hairs
– Found mostly on parapodia
* Parapodium (setae)
– Respiration and movement
* Lack a clitellum
* Mostly marine
* Largest annelid group
– 12,000 species
* Variety of habitats
– Ocean floors (Errantia)
– Tube dwellers (Sedentaria)
class polychaetes
which class?
-Sometimes called “night crawlers” that
burrow in moist rich soil and usually
live in branched interconnected tunnels
* Range in size from 12 to 30cm long but some giant worms grow up to 4m long with more than 250 segments
* Remain on the surface during damp, rainy weather with anus or mouth protruding
* Burrow deep underground and go dormant coiled in a slime chamber during very dry weather
* Paired epidermal setae are set in a sac and project outwards from body wall
* Earthworms are vital to soil aeration and nutrient recycling due to their constant motion within the soil
Class Oligochaeta
which class?
500 species of leeches
* Most freshwater
– Others are marine or
completely terrestrial
– Prey on small invertebrates
or feed on the body fluids of
larger vertebrates
* External structure
– Lack parapodia
– Setae absent in most
– Body subdivided into annuli
– Loss of septa (Lacunae)
– Anterior and posterior
suckers “true leeches”
class hirudinea
which phylum?
Known as “peanut worms” because when disturbed, they contract to a peanut shape
– Approximately 250 species of
benthic marine worms
– Sedentary, living in burrows of
mud or sand, snail shells, coral
crevices, or among vegetation
– Most are restricted to tropical
zones
– Some are tiny, slender worms,
but most range from 3 to 10 cm
in length
phylum sipuncula
The _____ is a rasping, protrusible, tongue-like organ that is found in almost all molluscs except bivalves.
radula
In molluscs, the mantle creates a space between itself and the visceral mass which houses the ______ organs.
respiratory
The class ______ is a small group of bottom-dwelling marine organisms that usually lack radula and gills.
Solenogastres
The class ______ are mostly burrowers that orient themselves vertically, with the terminal mantle cavity and gills at the entrance of the burrow. They posses an oral shield as well as a radula and gills.
Caudofoveata
Molluscs called chitons belong to the class
Polyplacophora.
The class Solenogastres is similar to the class Caudofoveata except that they usually lack ___ and ____.
radula and gills
______ are small, have a low rounded shell, and a creeping foot, and until the 1950’s, they were thought to be extinct.
Monoplacophora
The class Polyplacophora contains molluscs called
chitons.
Serial repeated organs (such as gills and metanephridia) are characteristic of the molluscan class
Monoplacophora
Snails, slugs, and limpets are examples of molluscs in the class
Gastropoda
The ctenidium are
_____ in the primitive condition found in most prosobranchs
gills
In gastropods, during the veliger stage the relative positions of the shell, digestive tract, anus and mantle cavity all change in a process called
torsion
or spiral winding of the shell occurs in the larval stage and originated in ancestral gastropods earlier than torsion.
coiling
The valves, or Blank______, of bivalves are drawn together by adductor muscles.
shells
Respiration in most gastropods is performed by a Blank______.
osphradium
proboscis
ctenidium
radula
ctenidium
Mollusks called ______ are mostly sedentary filter feeders and have two shells, no head, and no radula.
bivalves
______ have the most elaborate nervous and sensory system of all of the molluscs.
Cephalopods
The head of an annelid is the first true segment.
t/f
false
oligochaeteta
hirudinida
polychaetes
match with the following:
leeches
marine worms
earthworms
oligocaeteta: earthworms
hirudinida: leeches
polychaetes: marine worms
select which structures can be found on a typical errant polychaete:
setae
parapodia
sensory organs
clitellum
setae
parapodia
sensory organs
What is the lip-like structure that helps an earthworm to move its food into its mouth?
prostomium
A marine polychaete that is 10 cm long, iridescent, motile, and has parapodia is called a(n)
siboglinid.
mollusc.
errant polychaete.
oligochaete.
errant polychaete.
The ______ of an errant polychaete surrounds the mouth and can bear setae, palps, or jaws.
prostomium
parapodium
peristomium
pygidium
peristomium
In terms of reproduction, polycheates usually
are hermaphroditic
are parthenogenic
have two sexes
have two sexes
The portion of the polychaete nervous system that runs the length of the body is the
single ventral nerve cord
double dorsal nerve cord
double ventral nerve cord
single dorsal nerve cord
double ventral nerve cord
The end of the excretory organ that opens into a coelomic compartment in the polychaete body is the _______.
nephrostome
nephridiopore
nephrocoel
nephrostome
Select all of the following that describe oligochaetes.
They lack setae.
Some are parasitic.
Most are terrestrial or freshwater.
Most live in marine habitats
They lack parapodia.
Some are parasitic.
Most are terrestrial or freshwater.
They lack parapodia.
In most earthworms, each segment bears pairs of ______ which anchor the body during locomotion.
radioles
setae
clitella
parapodia
setae
What is the “brain” of an oligochaete?
Pair of cerebral ganglia
Ventral nerve cord
Giant axons
Nerve ring
Pair of cerebral ganglia
Leeches differ from other annelids in that they possess
less specialization
setae
distinct coelomic compartments
a fixed number of segments
a fixed number of segments
