lecture 15 Flashcards
what classes make up clade aplacophora
caudofoveata
solenogastres
Aplacophora habitat
they all marine
does aplacophora have shells?
no, lack shell plates, they have pointy calcareous sclerites
are are mfs in clade aplacophora
whatdo they lack
marine worm like burrowers lacking eyes and metanephridia
class caudofoveata characteristics
do not have foot
have radula
class solenogastres
do not hav ctenidia and some lack radula
have small foot
where is foot in solenogastres
in ventral groove
solenogastres how many species
260
caudofoveata # spp
130
what is class polyplacophora
the chitons
how many species polyplacophora
930 spp
where does polyplacophora dwell
they are marine
what type of shell does polyplacophora have
7-8 flat dorsal shell plates
what does polyplacophora mantle bear
spicules
what is the extension of mantle called
girdle
how many pairs of ctenidia in polyplacophores
6-90
where are eyes in polyplacophora
not on head–> poorly developed
on the surface of shell plates there is hundreds of tiny light sensing eyes
how do polyplacophora eat
rasping algae off solid substrate
how are radula teeth strengthened in some polyplacophora species
magnetite
conchifera
where the rest of the molluscs fall
conchifera shells
univalved shell
what clade is class monoplacophora inn
class chonchifera
how many spp monoplacophora
35
monoplacophora shell
single cap like shell
how are monoplacophoras known
fossils from cambrian until 1952 when they found live mfs
what habitat monoplacophora
marine
do monoplacophora have metanephridia
ifso how many pairs
3-7 pairs of metanephtridia
do monoplacophora howmany pairs ctenidia
3-6 pairs
how many pairs pedal retractor muscles in monoplacophora
8 pairs
monoplacophora phylogeny debate
thought to be missing link b/w mollusca and annelida( seg worms)
-but analysis proves wrong
-because of haphazard association of organs
how do monoplacophora feed
scrape material off hard substrate
what clade is class gastropoda
conchifera
wow crazy about gastropoda
largest class of molluscs
how many spp of molluscs
32000
symmetry of gastropods
asymmetrical adults
shell of gastropods
single spiral shell where body is withdrawn
what us opening of shell where body emerges
aperture
what is the main axis of shell
columella
what is each turn of shell called
whorm
what is a body whorl
where body currently retracts into
spire
rest of shell
what is the larval shell caleld
protoconch
what is lost independently in many gastropods
shell
aperature on left
sinistral
aperture on right
dextral
how does body attach to inside of shell
columellar muscle
where are tentacles gastropod and how many
head, they are sensory
1-2 pairs
foot gastropod
well developed, secretes mucus for movement
prosobranch condition
gills located anterior to heart
opisthobranch
gills located posterioor to heart
pulm
lung
gastropods that lack gills are
terrestrial or secondarily freshwater
pulmonates
movement in gastropods
-some swim with fin extentions
-movement via crawling
how is crawling achieved
muscular waves
aids muscular waves
pedal mucus
direct waves
forward direction waves
retrograde waves
reverse direction
what properties of pedal mucus change
cause it to be sticky when foot moving slow and slippery when moving fast
gastropoda feeding
rasping grazers of algae
-presumably ancestral
cone snails
predatory snails w harpoon radula
how does harpoon stylets work in cone snails
injects venom that paralyzes victim
nudibranchs what do they eat?
feed on cnidarians
what helps nudibranchs eat
kleptocnidism
what is kleptocnidism
prevents cnidae from firing
why are some nudibranches brightly coloured
they store toxic chemicals from poniferan prey
aposematism
Aposematism meaning
tell visual predators to stay away
gastropoda reproduction
internal fertilization and copulate w very long penis
gastropoda development
classic protosome development
- trochophore larva stage
what stage do many marine gastropods share?
the veliger
the trochophore
what does the veliger have?
operculum and velum
velum
two cilliated lobes
what velier uses to swim and feed
veliger
larval stage following trochophore
terrestrial larval stages
reduced and inside egg
what stage does tortion take place
veliger
what is tortion
visceral mass and mantle rotate 90 to 180 degrees, moving hind end towards head
what does tortion result in
-mantle cavity, openings to anus and excretory systems become anterior
-body asymmetries
-twisted nervous system
what happens to gastropods that lost their shell
they detort
detortion
animal symmetrical on outside and asymmetrical on inside
