Crustaceans

arthropoda

what phylum are crustaceans in?

80

insects and crustacea make up what percent of animal species

their hard exoskeleton

what are crustaceans names for

2 pairs of antennae

main distinguishing feature of crustaceans

having 2 branches

what does biamous mean?

marine

habitat of most crustaceans

pair of mandibles and 2 pairs maxillae

in addition to antennae what is on the crustacean head?

less

do derived crustaceans have more or less segments than ancestral forms?

crustaceans

closest arthropod relative to insects

genus Calanus

probably the most abundant animals in the world

head, thorax, abdomen

typical major body tagmata

cephalothorax

\n In most crustaceans, one or more thoracic segments are \n fused with the head. What is this segment called?

16-20

how many body segments do current crustaceans have?

carapace

dorsal cuticle found in many crustaceans that may \n cover most of body including thoracic and abdominal segments or just the cephalothorax in some species.

chitin, protein, and calcareous material

what is the cuticle made of?

flexibility

what do joints allow?

telson

end of abdomen ends that bears anus

tergum

Dorsal cuticular plates

pleurites

lateral plates

sternum

ventral plates

dioecious

are most crustacea monoecious or dioecious?

seminal receptacle

where is sperm introduced to females

ventral side of abdomen

where do female crustaceans hold eggs

Hemocoel

major space in arthropods that came from persistent blastocoel which is filled with blood

basis and coxa

two parts of protopods

biamous plan

what basic plan is seen in crayfish appendages?

serial homology

condition where biamous appendages are homologous but may have been modified to have different functions

muscular and nervous

what systems in the thorax and abdomen show segmentation

antagonistic

Most muscles arranged as _________ groups (perform opposite functions) with flexors drawing limb toward the body and extensors straightening a limb out.

open

what type of circulatory system?

1

how many chambers in crustacean heart?

arteries, no veins

do crustaceans have arteries or veins

Hemolymph

name for crustacean blood

pigments

why can hemolymph be different colors

antennal glands

green glands in excretory system

ganglia

Double ventral nerve cord has a pair of ______ for each segment to control appendages, muscles, and other parts

ommatidia

photoreceptor units that make up compound eyes

cornea

covers each eye

facets

small squares and hexagons in cornea called that focus light.

nauplius

Common larval form with uniramous first antennules. First larval form after the egg

exocuticle and endocuticle

what two layers is the procuticle divided into?

endocuticle

dissolved by enzymes during molting

exocuticle and epicuticle

layers of cuticle shed by animal during ecdysis

takes large gulp of water to crack shell at joint

how does an animal break cuticle in ecdysis?

ecdysis

the shedding of the old cuticle

molting

the physiological process of making a larger cuticle

suspension feeding, predation, scavenging

feeding habits found in crustaceans

2

how many parts to a crayfish stomach?

order isopoda

one of the few truly terrestrial crustaceans that also have \n marine and freshwater forms

do not have insect cuticle to conserve water

why must isopods live in moist environments?

photophore

light-producing organ that gives krill bioluminescence

they are external

what is unique about the gills of krill?

order decapoda

Approximately 18,000 species which includes crayfishes, lobsters, crabs, and true shrimp

broader, reduced

Crabs have a __________ cephalothorax and __________ abdomen as compared to crayfish or lobsters.

eyes and statocysts

largest sense organs in crustceans

distal retinal, proximal retinal, reflecting pigment

3 sets of eye pigment cells

ommatidium

optical units made up of the three eye pigments that form the compound eye

monoecious

Barnacles are _________ but generally cross-fertilize

sacs on abdomen

where do most crustaceans brood eggs?

epidermis

what secretes cuticle

intermolt phases or instars

growth phase of molting where animals grow with soft tissue increasing in size until there is no space within the cuticle

premolt phase

molting phase where body fills cuticle and epidermal cells enlarge prior to ecdysis

vasa deferentia

located on the median side at the base of the fifth pair of walking legs in crayfish

oviducts

located on the median side at the base of the third pair of walking legs in crayfish

seminal recepticle

located at the midventral line between fourth and fifth pair of walking legs