Subphylum Crustacea

Arthropoda Classification Phylum Arthropoda Subphylum Uniramia- (terrrestrial mandibulates) Class Chilopoda- centipedes Class Diplopoda- millipedes Class Insecta- insects Subphylum Crustacea- (aquatic mandibulates) lobsters, crabs, crayfish, shrimp, sow bugs (pill bugs), krill and barnacles Subphylum Chelicerata Class Arachnida- spiders, scorpions, ticks, and mites Class Merostomata- horshoe crab Class Pycnogonida- sea spiders Subphylum Trilobita- trilobites (extinct)

Ex. lobsters, crabs, crayfish, pill bugs, barnacles. Most are free-living & aquatic; however, some terrestrial & parasitic species exist.

*The representative species for Subphylum Crustacea is the crayfish.

Body Segmentation cephalathorax--covered by the carapace which is a single exoskeletal plate abdomen--composed of 6 segments, each covered by an exoskeletal plate.

Respiration/ Circulation 2 sets of feathery gills in lateral gill chambers along the thorax region. Covered by part of the carapace with openings on ventral side Maxillae- manipulate food when eating but also help push water through the gills Carbon dioxide is released from the blood and oxygen is picked up

*Crayfish can hold water in their gill chamber and extract oxygen from the water while they’re on land, much like we would hold our breath under water.

Respiration/ Circulation Oxygenated blood is moved to the pericardial sinus which surrounds the heart The blood enters the heart through tiny openings The blood is forced through a series of arteries that empty into spaces within the body cavity. Body cells pick up oxygen from the blood and release carbon dioxide to the blood. The deoxygenated blood collects in the sternal sinus The deoxygenated blood is passed through gills where it becomes oxygenated and then back to the pericardial sinus *Green glands- near the base of the antennae, filters out waste material which exits through a pore anterior to the mouth

Nervous System Ventral nervous system Compound eyes sit on top of movable stalks Antennae- appendages for taste and touch Antennules- short antennae, also aid in balance Statocyst- at the base of each antennules, sacs contain several grains of sand and lined with tiny sensory hairs, this organ helps with balance

Reproduction The crayfish cannot reproduce asexually It is capable of regeneration as a method of repair. {if it loses a limb in an attack by a predator, it can re-grow the limb, but if you cut the crayfish in 1/2 it will not produce 2 new organisms.} Sexual reproduction

After its 1st year, a crayfish will molt about twice a year After its 1st year, a crayfish will molt about twice a year. (seven x in its 1st year.)  

Other Crustaceans Sow bug (pill bug)-"roly-poly" is a terrestrial crustacean must live in moist environments to keep its gills moist Barnacle--sessile animals that live in calcium containing shell-like exoskeletons, attach to virtually any underwater object. Daphnia--the water flea--is a tiny fresh water crustacean.

Sow Bug or Pill Bug DAPHNIA

http://www.youtube.com/watch?v=49Aev-HA9R4