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115 terms

biology ch 35

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a diverse group of invertebrates such as clams,slugs,squids,and octupuses
Phylum Mollusca
mollusk are
coelomates
what does the latin term of mollusks mean
soft
most aquatic mollusk and annelids have a larvae stage called a
trochophore
wat contains the heart organs of digestion,excretion, and reproduction
visceral mass
the head foot consist of what
the head, which contains the mouth and sensory structures; the foot- a large muscular organ for locomation
a layer of epidermis that covers the visceral mass and is protective
mantle
the gills are protected within the
mantle cavity
the nervous system consist of paired clusters of nerve cells called
ganglia
the main feeding adaption of many mollusk is the
radula
what does gastro mean
stomach
what does poda mean
foot
what group consist of snails abalones conchs
gastropods
gastropods undergo the process of _______ during larvael stage
torsion
do gatropods have a open or closed circulator system
open
the heart pumps hemolymph from gills or lungs into the what
hemocoel
_____ live in moist and aquatic enviroments
snails
most _____________ have soft bodies and some hard shells
mollusks
the ________ is limited space around the mollusks heart
coelom
the disadvantage of a shell is offset by
having gills
most mollusks are
billaterally symmetrical
In most mollusk, the mantle secretes one or more hard shells containing
calcium carbonate
what is the largest and most diverse class of mollusks
Gastropoda ( called gastropods)
most gastropods, including snails, abalones, and conchs have
a single shell
during larval development gastropods undergo the process of
torsion
gastropods have an open circulatory system in which the heart pumps _____________ from gills or lungs into the hemocoel.
hemolymph
Gastropods are most active
at night
snails live
in moist and aquatic enviroments
most snails locate food using eyes at the end of
their tentacles
how do snails survive dry periods
by retreating into their shells and sealing the opening with their mucus plug
Nudibranch gastropods are
marine and lack shells
slugs are
terrestial and lack shells
Pteropods or "sea butterflies"
have a foot that is modified into a winglike flap and used for swimming rather than crawling
Bi-
means two
the class Bivalvia includes mollusks such as
clams, oysters, and scallops
Bivalves are called that because
their shell is divided into two valves connected by a hinge
each valve consist of
three layers,
most bivalves are what type of feeders
sessile filter feeders
Bivalves lack
a distinct head and have three pairs of nerve ganglia
clams are bivalves
that live buried in mud or sand
the mantle cavity of a clam is sealed except for a pair of hollow, fleshy tubes called
siphons
water enters through the
incurrent siphon
water leaves through the
excurrent siphon
when do oysters become attached to a hard surface
early in their development
How do scallops move through the water
by repeatedly opening their valves and snapping them shut
The class Cephalopoda includes;
octopuses, squids, cuttlefish, and chambered nautiluses
cephalopds means
"head-foot"
Cephalopods are specialized
as free- swimming predators
Cephalopods have
tentacles, bear like jaws on the head, a very advanced nervous sysytem, and a closed circulatory system
what do many cephalopods use to disquise and hide themselves
pigments
Cephalopods with ten tentacles
squids
squids propel themselves by
pumping jets of water with the mantle through an excurrent siphon
Cephalopods with eight tentacles and are similiar to squid
octopuses
what is the only existing cephalopod that has retained its external shell
chambered nautilus
the chambered nautilus shell is
coiled and divided into a series of chambers, the body is confined to the outer most chamber
The phylum of Annelids is
made up of bilaterally symmetrical segmented worms
Annelids phylum include
common earthworms, featherduster worms, and bloodsucking leeches.
Annelid means
little rings and refers to the many body segemnts
Annelids have a true coelom that is
divided into seperate compartments by partitions
Most annelids have external bristles called
setae( singular; seta)
Some annelids have fleshy protrusions called
parapodia(singular;parapodium)
Oligochaeta means
few bristles
Annelids of the class Oligochaeta generally live
in the soil or in fresh water and have no parapodia
the most familiar member of the Oligochaeta class is the
earthworm
An _____________ has over 100 nearly identical segments
earthworms body
_____________ and ________________ muscles line the earthworms interior body wall
circular and longitudinal
________________ is made possible by segmentation
locomation
typhosole
are in the intestines
Earthworms ingest soil as they
burrow through it
Soil moves through these structure;
mouth, pharynx,esophagus,crop,gizzard intsetine(includes the typhosole) and anus
what plays an important role in the condition of the soil
earthworms
the nervous system of an earthworm consist of
a chain og ganglia connected by a ventrl nerve cord
____________________ are found in all segments but are concentrated at the anterior end
sensory structures
cellular waste and excess water are excreted through
nephridia ( ls a simple kidney)
____________and _________ diffuse through the skin, which contains many small blood vessels and must be kept moist.
Oxygen and Carbon dioxide
Contractions of the ________________ and the dorsal blood vessels force blood through the closed circulatory system
aortic arches
dorsal
runs on the top
ventral
runs on the bottom
Earthworms are _______________________
hermaphrodites, but an individual worm cannot fertilixe its own eggs
during________________, earthworms press their ventral surfaces together
mating
during mating thay are held together by their setae and a film of mucus secreted by each worm's
clitellum
The _________________ from each worm move through the mucus to the seminal receptacle of the other.
sperm
The clitellum secretes a tube of mucus and
chitin
______________________ occurs inside the tube, which forms a protective case for the young worms
fertiliztion
Polychaeta means
many bristles
Poly means
many
Polychaetes differ from annelids in that they have
an antennae and specialized mouth parts
Polychaetes are the only annelids that have a
trochophore stage
what is the smallest class of annelids
Hirudinea
Hirudinea consist of
500 species of leeches, which have no setae or parapodia
Many leeches are ___________________ but some are parasites that suck blood from animals
carnivores
key characteristics of mollusks
sedentary filter feeders,
the body plan of mollusk include;
the viceral mass, the head- foot and the mantle
what is advantage of true coelom over pseudocoelom
with a coelom the muscles of the body wall are seperated from those of the gut, therefore the body wall muscles can contract without hindering the movement of food through the gut. A coelom also provides a space where the circulatory system can transport blood without interference of internal organs
In which phyla of animals is the larva trochophore stage found
Mollusca
For what purpose is a radula used
feeding
why are land snails more active when the air around them is moist
the thin membrane lining the mantle cavity must be kept moist to allow gases to diffuse through it
name three major classes of mollusk
Gastropoda, Bivalvia, and Cephalopoda
describe the key characteristics of mollusks
external shell, head. radula, locomaotion
Compare circulatory system of 3 major classes of mollusk
gastropods have open circulatory system meaning the circulatory fluid called hemolymph does not remain entirely within the vessels; Cephalopoda have a closed circulatory system, it transports fluid more rapidly than an open circulatory system, thus nutrients, oxygen, and carbon dioxide are carried quickly through the body;Bivalva have
identify the structure that provides the basis for dividing annelids into three classes;
the number of setae and the presence or absence of parapodia
Advantages of body segmentation
if one segment becomes disabled, the others can still function; movement is possible by segmentation; segmentation enables different parts of the body to carry out variuos functions independently;
describe structural adaptations of earthworms
look up
compare three classes of annelids
Oligochaeta- Polychaeta- Hirudinea
how are an earthworms circular and longitudinal muscles used in locomation
the worm anchors some of the middle segments by their setea & the ability to contract the circular muscles in front of the middle segments allows the worm to move
why does an earthworm require a moist environment to survive
an earthworm requires a moist environment to survive because it diffuses oxygen and carbon dioxide through the skin, which contains many small blood vessels- this exchange of gases can only take place if the skin is moist, secretions of mucus and the presence of a thin cuticle also help keep the worms skin moist
to which phylum do leeches belong
annelida
To which phylum do cuttlefish, octopus, squid & chambered nautiluses belong
molluska
what is the largest and most diverse class of mollusks
gastropoda
gastropod
from the greek gaster, meaning stomach amd "pous" meaninf foot
which class of mollusk undergo torsion during the larva development
gastropods
nudibranch means
naked gill, which refers to the fact that gas exchange occurs during the entire body surface of these animals
trochophore
is a larve that develops from the fertilized egg of most mollusk and annelids
Parapodia are a distinguishing characteristics of which class of annelids
hirudinea
Annelids are divided into three classes based partly on the number of which of the following
setae