Phylum Chordata

What are the four major traits of cephalochordata

Wheel organ, serial gonads, notochord extends into the head and is built of discoidal lamellae

Why was cephalachordata thought to be sister taxa to vertebrata?

fish like from the get-go. Long, laterally compressed, with myomeres (longitudinal muscles), bilateral symmetry

Where do cephalochordata live?

lives in the sandy habitat with most of the body in the sand and the cirral fan sticking out to breath and/or collect food

How do they bring water into the stomach?

The wheel organ is in the buccal cavity, which is made of ciliated folds that create the feeding current

What makes the nerve system special

No cephalization, there is a small concentration of nerves but no brain

Explain how neurolation happens

The ectoderm, a layer of cells on the embryo's surface, transforms into the neural plate, which then folds inward from posterior to anterior to form the neural tube.

How do cephalochordates move?

They are able to change the shape of the notochordal cells to modify the amount of bending along the body

What makes up the circulatory system of cephalochordata?

contractile vessels and veins

How does the nephridial system work?

Blood is pumped from vessels across podocytes and flame-like cells to the atrium for reabsorption or secretion

What makes the cephalochordata nervous system special?

There are a lot of specialized nerves that come off the spinal cord, but there is no cephalization of the head

Is the larval stage of cephalochordata bilaterally symmetric why?

Initially the mouth is on the left and gill slits are open to outside on right

What are the two classes of hemichordata, and what is their lifestyle?

Enteropneusta are all solitary and pterobranchia are all colonial

What are the three main segments of enteropneusta?

proboscis, collar, trunk

How do enteropneusta move?

They move using their muscular proboscis as a foot to drag or peristaltic waves to dig

How do you orient enteropneusta?

gill pores are dorsal and proboscis is anterior

What are the coelomic spaces in enteropneusta?

proboscis has the protocoel, the trunk and collar and trunk have the mesocoel

How do you differentiate gill slit and gill pore

Gill slit moves water from digestive system to branchial sac then moves from the branchial sac out the branchial pore to outside the body

What is the only feature that hemichordata shares with the phylum chordata

The only feature that hemichordata clearly share with the chordata are the gill slits

What gives hemichordata gills the U shape

tounge bars have blood vessels that perform gas exchange

Why are proboscis of enteropneusta more sturdy than the end of the trunk

the proboscis skeleton

What are the 2 main features of hemichordata larvae

ciliated band and a 3-part gut

What grows faster a feeding or non feeding hemichordata?

non feeding

How are features in enteropneusta modified in pterobranches

Proboscis is a modified foot, the collar is a modified lophophore, the trunk is shortened with a U-shaped gut

How are pterobranchia colonies connected?

stolons through tubes

What are the three subphyla under Chordata?

cephalochordata, urochordata, and vertebrata

What are the three classes of urochordata and what is their living style

ascidiacea (solitary and colonial), thaliacea (solitary), and appendicularia (colonial)

What are the four characteristics that define urochordates

notochord, hollow dorsal nerve tube, post anal tail and gill slits

How does water move through urochordates, and how do they eat?

by pharyngeal cilia and feed with mucus net produced by the endostyle, moved by pharyngeal cilia, collected by the dorsal lamina, and moved to the esophagus

What are the three ascidian orders and what kind of gill structures do they have

Aplousobranchia (“simple gill”, planar basket wall, transverse blood vessels), Phlebobranchia (“blood-vessel gill“ planar with transverse and longitudinal vessels), Stolidobranchia (“folded gill“, pleated basket walls, transverse and longitudinal vessels)

What are the three living styles of ascidians

colonial (w individual in/out OR w seperate in shared out), social, and solitary

What are the names of the pelagic tunicates in the class Thaliacea

Salps, Pyrosomes, and Doliolids

How do pelagic Thaliacea move?

beating of cilia through pharyngeal basket cases, causing them to move in the direction of the anterior end