Chapter #33- Echinodermata/Chordata

Deuterostomia includes what phylum

echinodermata

what are sea stars and echinoderms characterized by

radial cleavage

What do echinoderms have

a water vascular system and tube feet

what does the water vascular system do

network a hydraulic canals branching into tube feet that function in locomotion, feeding, and gas exchange

4 classes of Echinoderms

asteroidia, ophiuroidea, echinoidea, holothuroidea

Class Asteroidea are

sea stars that have multiple arms radiating from a central disk, arms bear tube feet that can be regrown if lost

Class Ophiuroidea are

brittle stars that have a distinct central disk and long, flexible arms they use for movement

Class Echinoidea are

sea urchins and sand dollars that have no arms but have 5 rows of tube feet

Class Holothuroidea are

sea cucumbers that have a reduced endoskeleton, they have 5 rows of tube feet

Chordates

bilateral animals that belong to the superphylum Deuterostomia

4 key characters of chordates

notochord, dorsal hollow nerve cord, pharyngeal slits or clefts, muscular post-anal tail

notocord

longitudinal, flexible rod that provides skeletal support between the digestive tube and nerve cordn

nerve cord

develops into the central nervous system or brain and the spinal cord

pharyngeal clefts

develop into slits that open to the outside of the body

4 functions of the pharyngeal slits

feeding structures, gas exchange, develop into parts of the ear, head, and neck

Muscular post-anal tail

chordates have a tail posterior to the anus

3 subphyla of chordata

cephalochordata, urochordata, vertebrata

Cephalochordata and Unochordata examples

lancelets, seasquirts- filter feeders that retain basic chordate body plans

Craniates

clade within phylum chordata, synonymous to vertebrata

what characteristics do craniates share with vertebrates

skull, brain, eyes, and sensory organs

in craniates pharyngeal clefts evolved into

gill slits