Phylum Chordata - Subphylum Tunicata: Class Ascidiacea

Common names for members of Class Ascidiacea: (3)

Sea squirts, tunicates, and ascidians

In Larval Ascidians: the ___ is confined to the ___

Notochord; tail

Uro

Tail

Urochordate

Tail chordate

In Larval Ascidians: the ___ has ___ called the ___

Pharynx; slits; protostigmata

The ___ in Larval Ascidians: ___

Pharyngeal gill slits; protostigmata

In Larval Ascidians: the ___ contains ___

Nerve cord; visceral ganglion

In Larval Ascidians: the ___ is an ___ of the ___ that functions as a ___

Visceral ganglion; anterior swelling; nerve cord; brain

In Larval Ascidians: the ___ is not ___

Mouth; functional

In Larval Ascidians: the ___ is blocked by a ___

Mouth; tunic

Larval Ascidians have a ___: an outer covering made of ___

Tunic; cellulose

The ___ of Ascidians: persists into ___

Tunic; adulthood

The Larval Ascidians survives on ___ because the ___ and they ___

Reserves; mouth is blocked; cannot feed

The structures a larval ascidian uses to attach itself to substrate

Adhesive papillae

2 factors of the metamorphosis:

Resorbs tail and major reorganization of internal structures

2 Main Arrangements/Body Types in Ascidians

Solitary and colonial

Solitary ascidians aka:

Simple ascidians

Colonial ascidians aka:

Compound ascidians

___ ascidians: tend to be the largest species

Solitary

___ ascidians: individuals are usually small

Colonial

Colonial ascidians colonies can grow to ___ in diameter

12 to 15 cm

Colonial ascidians can reproduce by ___ so ___ can be ___

Budding; many individuals; connected

Individual ascidians in a colony

Zooids

The simplest ascidian colony: ___ that are ___ (____) but connected by a ___

Zooids; physically separated; not touching; stolon

Most complex colonial ascidians: numerous ‘___’ within the same ___

Subcolonies; translucent tunic

Each subcolony in a colonial ascidian has 1 ___ and multiple ___

Atrial siphon; buccal siphons

Atrial siphon: water ___

Exit

Buccal siphons: water ___

Intake

Atrial siphon: the ___ of ___

Collective outflow; many zooids

Buccal siphon: the ___ for ___

Intake; one individual zooid

___ reproduction occurs in ___ forms by ___

Asexual; colonial; budding

___ reproduction occurs and most are ___

Sexual; hermaphroditic

Sexual reproduction: ___ typical ___ from the ___

Gamete; shed; atrial siphon

Sexual reproduction: ___ occurs in the ___ and ___ develop from there

Fertilization; external environment; tadpole larvae