Tunicata

Adult Tunicate are

fairly simple filter feeders

The Larval phase of the Tunicates

are simlar to other Chordates

The Larval phase characteristics are

Dorsal Hollow Nerve chord, gill slits, notochord, and Post anal tail

4 basic Variations on the Tunicate Bauplan:

Single Benthic Filter feeders, Colonial Benthic Filter feeders, Single Pelagic filter feeders, and colonial pelagic filter feeders

The Benthic forms have a tough outer layer called

Tunic

Tunic is composed of

Cellulose-the same material wood is made of

Tunicates

concentrate heavy metals in their tissues as a defense. The metals are kept in highly acidic state and are unpalatable to fish

The metals are:

Vanadium, Lithium, Nobium, Iron, and Tantalum

Urochorodata

“tailed cord”

Larvae=

ascidian larave

Central Nervous system with 3 components:

Hollow Anterior Sensory Vesicle, Visceral Motor Ganglio, Tubular Caudal Nerve

Anterior Sensory Vesicle

genetically homologous to the right cerebrum

Eutely is

(True end) when fully developed have a set number of cells

simple eye

ocellus (gene Pax6)

Statlith-statocyst and they express

all major NT’s, cholinergic muscle, but no myelin

Have coronet cells which are

glial cells

Ganglion

a group of neuron bodies

The Larvae are

Photophobic (can be trained to avoid certain places and have a minute memory) it also have 4 characteristic of chordates

The Adult

may be Pelagic(swimming), Sessile, Pelagic colony or aggregation, and may be sessile colony of aggregation

Sessile filter feeding nervous system has a

reduced nervous system

Colonial types has

an integrated nervous system

Pelagic individuals

nervous system similar to larvae

The nervous systems of Benthic forms are

simplified and reflect their simplified lifestyle

Tunicates have

hair cells