L11: Phylum Echinodermata Flashcards
What features differentiate echinoderms from animals previously discussed What anatomical features are unique to echinoderms Describe the water vascular system and its functions Describe skeletal elements present in echinoderms Indicate why some echinoderms are considered keystone species
What animals are in the phylum Echinodermata
Sea stars, urchins, sand dollars, sea cucumbers, etc
Where do echinoderms inhabit?
Marine environments
T/F: Echinoderms are protostomes
False - deuterostomes
radial, indeterminate cleavage, anus from blastophore
What kind of symmetry do adult forms have
Pentaradial symmetry
What symmetry do echinoderm larvae have?
Bilateral
What feature do echinoderms have that make em extra special
Water vascular system
Describe briefly the nervous system of echinoderms
Nerve ring, radial nerves, nerve net
What are the functions of the water vascular system
Feeding
Locomotion
Gas exchange
Overall, describe the location of the water vascular system
Located within coelomic cavity, consisting of canals and tubules that span throughout animal
Pertaining to the water vascular system..
Describe the ring canal
Encircles digestive tract and connects outside to inside via the stone canal and madreporite
Pertaining to the water vascular system..
What is the function of the aboral/oral hemal rings
Projects branches into arms, like a circulatory system
Pertaining to the water vascular system..
Describe the radial canals
Canals projected into each arm of the animal
Pertaining to the water vascular system..
Describe the ampulla
When squeezed, pushes water into the tube foot when squeezed foot to create suction and allow for movement
Pertaining to the water vascular system..
Describe the tube foot
On underside of animal
Acts as suction cup that can contact substrate
Used for gas exchange with surrounding water
The dermal branchiae on echinoderms are used for what?
Gills, extensions of coelomic cavity to surface, for gas exchange
What is the structure Pedicellaria used for in Echinoderms?
To clear debris off its surface
T/F Seastars undergo metamorphosis
True! Brachiolaria to juvenile sea star
What are the 5 major classes of Echinodermata?
Asteroidea
Ophiuroidea
Echinoidea
Holothuroidea
Crinoidea
Describe the class Asteroidea
Standard sea stars
Benthic animals
Predatory
Pertaining to the water vascular system..
What is the madreporite
Plate-like structure where seawater enters the water vascular system
Describe class Ophiuroidea
Brittle stars, basket stars
More simple than Asteroidea
Branched/unbranched ars
Water vascular system not used for movement
No extension of gut into arms
Tube feet lack suction discs and ampullae
Madreporite on oral side
How do Ophiuroidea move?
Muscular arms allow for grabbing onto things and pulling themselves along
Describe Class Echinoidea
Urchins, sand-dollars
Have outer plates that encompass it
10 Interambulacral plate (spines)
5 ambulacral plate (tube feet)
Describe how class Holothuroidea (sea cucumbers) respire?
They bring up water from the rectum into the respiratory tubules. The respiratory tree can then contract to push water out of the rectum
