Labs 8+9

Nov 5-6

Fossil echinoderm

Class Blastoida

-mouth on center of ridged end 

Pateria aboral surface

madreporite, papulae (finger shaped, function as gills), spines 

Oral surface of a starfish

Includes ambulacral grooves

Internal anatomy of starfish

Pyloric stomach, cardiac stomach, pyloric caeca, gonads, ampullae of tube feet, stone canal, ring canal, radial canal

How would a sea cucumber and pisaster respond to being attacked by a sun star? 

Sea cucumber - undulative motion to “swim”

Pisaster - used pedicellaria balls to attack solaster tube feed 

Response to intracoelomic injection of KCL in holothuroids?

Evisceration

Brittlestar external anatomy

Spines, central disk, segments (composed of calcareous ossicles)

bursal slits, genital plate, arm shields, mouth

Unique eye cups in sea stars 

-Ommatidia

-hundreds per eye 

How do sand dollars feed?

Food looks like it is transported into ambulacral grooves, moved by both spines and tube feet towards mouth

Chordate Taxonomy

Subphylum Urochordata

• Class Asciadicea

• Class Larvacea

• Class Thaliacea

Subphylum Cephalochordata

Urochordata general characteristics

marine filter feeders, have a tough covering called the tunic, a thin tissue layer made of water spicules, and polysaccarides that surrounds the body 

Urochordate classes

Ascidiacea (all the ones we saw) - sessile, well-developed tunic, pharyngael gill slits, lack dorsal hollow nerve cord and notochord. (althou tadpole-like larvae have them). Can be solitary or colonial. Blood and tissues store high levels of heavy metals nd ammonium.

Larcacea - pelagic and tadpole-like, encase body in gelatinous house that filters food particles out of water and directs currents to help move.

Thaliacea - pelagic filter-feeders that resemble adult ascidiaceans. Includes salps. Move via jet propulation by cilia or muscles

Cephalochordata general characteristics

lancelets. Small fish-like animals, live partly buried in sand. Have well-developed axial musculature that they use for swimming

What connects colonial sea squirts?

Stolon 

Sea squirt circulatory system

-have a heart that pumps blood

-flow reverses every few seconds/minutes

Water flow in sea squirts

-from incurrent to excurrent siphons

-digestive material can indicate anus which is next to excurrent siphon

Tunicate internal anatomy

-sensory tentacles, pharyngael basket with stigmata (slits), tunic, mantle, atrium, heart, stomach, endostyle

Cephalochordate anatomy

Oral cirri, notochord, gill slits of pharynx, hollow nerve cord, muscle myomeres