Chapter 14- Echinoderms Flashcards
What is a pedicellariae?
they surround the spine. They keep the body surface free of debris, protect the papulae and sometimes capture food.
What is an ambulacrum?
Extends from the mouth to the tip of each arms where the tube feet project from
Madreporite
Mother pore
Leads to water-vascular system
How many stomachs does a star fish have?
Two! CARDIAC: larger which can be everted through the mouth during feeding PYLORIC: smaller & upper connects with pyloric ceca
How do sea stars feed?
The sea star inverts the cardiac stomach through its mouth and secrets digestive enzymes to begin digestion.
What does echinoderm mean?
Prickly skin
Where do the descend from?
Bilateral ancestors b/c their larvae are bilateral but become radially symmetrical
What causes the sea star make various postures?
Catch collagen:
Change from liquid to solid
Ability to have different postures w/o muscular effort
What is the largest group of echinoderms?
Brittle stars
Who does not have pedicellariae, papulae or anus?
Brittle Stars
Where is the Madreporite located on the brittle star?
Oral side, on one of the oral shield of ossicles.
What is bursae?
In brittle stars they have 5 pairs of invaginations opened towards the oral surface.
Water circulates through for exchange of gases.
What is the periproct?
The anus
What is the Aristotle’s lantern?
Where teeth are attached
What is the free-swimming larva of sea cucumbers called?
Auricularia
