13. Crustacea Flashcards
what is unique about crustaceans?
two pairs of antannae and biramous limbs
name four species of crustaceans
shrimps, crayfish, crabs and barnacles
what is special about the first pair of antannae and the second pair?
first pair is throught to be homologus to those in insects
second pair is only found in crustaceans. may be homologous to the fangs in archids (scorpians)
what is special about the mouths of crustaceans?
have one pair of mandibles (lower jaw)
two pairs of maxilla (upper jaw)
what is a carapace?
a part of the exoskeleton that is a hard shell which extends ventrally from the back of the head
what is a biramous limb? what is the terminology
two branches of limbs - the branch on the ouside is an exopodite and the inside is an endopodite
what is the exoskeleton made of in crustaceans and arthopods and what is one difference of the crustaceans exoskeleton compared to arthopods?
the exoskeleton is made of chitin. in crustaceans, both the epidcuticle and procuticle contain calcium carbonate which makes the exoskeleton stronger and less brittle than calcium carbonate on its own.
the exoskeleton epicuticle isnt waxy and waterproof like insects or arachnids
define haemolymph
fluid equivilent to blood in most vertibrates
define haemolglobin
the transporter - its a protein molecule (globin) in red blood cells. carries oxygen to the bod tissue in invertibrates
define haemocyanin
the trasnporter of oxygen in the blood plasma in arthopods and molluscs. its a protein. haemocyanin is not bound to blood cells
define what the haemocoel is
the body cavity of most invertibrates containing circuatory fluid. the haemocoel acts as a hydrostatic skeleton
how do crustaceans breath? two points
they breath through their gills and the gas exchange system is closed (opposed to insects which is open)
what happens during respiration (what happens to the oxygen - 2 points)
oxygen is diffused through the gills and is transported in simple solution in the haemolymph.
or
its is bount to blood pigments such as haemoglobin or haemocyanin
what class is a crab in?
malaostaca
what is the tagamata sequence of malaostraca? how many biramous limbs does each segement have?
5 segements in the head
8 segments in the thorax (each with a pair of limbs - maxillipeds)
6 segments in the abdomen (each with a pair of birmaous pleopods)
what are the two orders that come from class malacostraca?
order decapoda (crayfish)
order euphausiacea (krill)
what are the thorac limbs, pincers and pleopods used (in females) in the order decapoda?
thorac limbs used for walking
pincers used for offence and defence
pleopods in females used to carry eggs
how to euphausiacea feed and swim?
filter feeding through the first 6 appendages of the thorax. the endopodites allow them to swim
what type of clade are crustaceans? is there anythign that can be added to change this?
they are a paraphylectic clade (common ancestors but not including decendents). must include hexapods to make monophylectic (all decendents)
give 5 facts about the class remipedia
no tagamataion behind head
two pars of antannae
live in deep oceans
blind
hermphroditc (male and female sex organs)
what class are daphnia in?
branchiopoda
what are three orders of malacostraca?
order stomatopoda (mantis shrimp)
order isopoda (parisitic)
cirripedia (stalk and stalkless)
