lecture 17 cephalopod Flashcards
What is class scapholopoda
tusk shells
calss scapholopoda how many spp
500
what is scapholopoda shell like
tubular, tapering shell open at both ends
what does class scaphopoda lack
lack ctenidia and eyes and heart
habitat of scaphopoda
buried in soft sediment
what are captacula
very thin tentacles around scaphopod foot
how is water moved in and out of mantle in scaphopods
via vilia
what do captacula have?
sticky bulbous tips
what do captacula do?
put organic shit in mouth
how is food ground up scaphopoda?
internal radula
fertilization in scaphopoda
external
class cephalopoda
squids and shit
how many spp cephalopoda
750
characteristics of class cephalopoda
largest, fastest and most intellegent invertebrates
cephalopoda shell
absent or reduced
what is formed by the head and foot
arms, tentacles, cirri, and funnel
what is the difference from arms and tentacles
arms have suckers along all their length
tentacles lack suckers only at the tips
what are the appendages of nautiluses called?
cirri
what is different about cirri
they are retractible into sheaths and they are non elastic, lack pads and suckers
what is clade nautilida
excint mfs in cephalopoda
what is Ammonoidea
extinct mfs in cephalopoda
What is Coleoidea
contains octopodiforms and decapodiforms
nautilus how many ctenidia
two pairs
how many ctenidia extant groups excluding nautilus
one pair
how is water moved in ctenidia in cephalopods
not cilliated, so water moved by muscular action of mantle
decapodiforms circ system
closed circ system
also have accessory pumps associated w ctenidia(branchial hearts)
nautiluses shell
only cephalopod w external shell
has septa and siphuncle
siphuncle function
control buoyency
shells in other cephalopods
reduced inside body
internal shell cuttlefish vs squid
cuttlefish have calcareous cuttlebone
squid have chitenous pen
what extinct taxa had large external shell
ammonoids
extinct squids that had hard internal shells
belemnoids
what is funnel called and used for
siphon used for jet propulsion
how do octopuses move
they crawl
how do squids and cuddlefish move slowly
undulate fins
what are the color changing cells in cephalopoda
chromatophores
what are colour patterns used for
camouflage and social displays
how do chromatophores worlk
the pigment in an expanded chromatophore is displayed
what is ink used for
defense
eyes in cephalopods
are image forming
how do eyes work in cephalopods
retinal axons pass directly out of the back of the retina
nautilus eyes
pinhole cameras
cephalopoda diet
they are carnivores
how do cephalopods eat shit they catch
it is bitten with beak and injected with venom
what is beak made of
chitin
what is the exception to carnivore cephalopods
vampire squid
it eats detritus
what type of development in cephalopoda
direct development
how does copulation happen in cephalopods
spermatophores transfered via modified arm w groove
how is the cephalopod embryo fed?
internal yolk supply
what are some useful things about mullusca
shells used for decorations or currency
pearls and pearl buttons
dyes from snails
aquarium trade
most eaten out of invertebrates
what are byssal threads used by us
sea silk
how are molluscs important for parasites
intermediate hosts
