Lab 9 Flashcards
To what phylum, class, and subclass does this organism belong?
Phylum Echinodermata, Class Stelleroidea, Subclass Asteroidea
Adult echinoderms show _____ symmetry
Pentamerous radial
How are body surfaces designated in the Echinoderms?
“Oral” and “aboral” (anus)
What are the primary features of the echinoderms?
Posses water-vascular system consisting of coelomic canals and extensions known as tube feet
Have internal skeleton of calcareous ossicles
No cephalozation (instead divided into oral and aboral)
Show secondary penatmerous radial symmetry
What is the phylum, class, subclass, and genus of this organism? What fundamental trait does it have that members of class Ophiuroidea do not?
Phylum - Echinodermata
Class - Stelleroidea
Subclass - Asteroidea
Genus - Asterias sp.
Ambulacral groove, seen in the middle of each arm in the photo. Tube feet emerge from this structure in this subclass
Is the calcified surface of this organism part of the endo or ecto skeleton? What about the spines?
What is the name of region A?
What is structure B? What is it’s function?
Endo. Spines come from the calcified ossicles, so are also endodermic.
Region A is called the central disc.
Madreporite - Structure used to filter water into the water-vascular system of the seastar
What structures are located at A? What is their function?
What is located at B?
What surface of the sea star is this?
A - Tube feet. Extensions of the water-vascular system helping with movement
B - MOUTH
Oral surface
Identify the structures in the photo.
What is the function of structure B?
Smaller bumps may be present, folding out of the body wall and just barely poking out. What would these be?
A - spines
B - Pedicellariae
Function in pinching surface encrusting organisms as well as predators.
Would be papulae. Which are used in respiration
What is this a cross section of?
Identify all the structures indicated. Why do B and F differ?
What is the functional significance of the location of A?
Astarias arm.
A - ossicle
B - Papula
C - Coelom
D - Ampulla
E - Tube foot
F - spine
F does not to connect to the coelom. This is because B functions in respiration.
A is located in the endodermis, meaning it can grow with the body and Astarias has no need to molt
What is THISSS???
Juvenile seastar!
List the phylum, class, subclass of this organism. Name the indicated structures.
What does the oral surface of this echinoderm notably lack? What structures do they have instead
Echinodermata, Stelleroidea, Ophiuroidea.
A - Central disc
B - Mouth
Lack ambulacral grooves. Instead have platelike ossicles called shields through which the small feet emerge
List the phylum, class, subclass, and genus of this organism
Echinodermata, Stelleroidea, Ophiuroidea, genus: Gorgonocephalus
Name the phylum, class, and genus of this organism. What is the outer shell referred to? What is it derived from? How is it divided? Can one find the divisions externally?
Phylum: Echinodermata
Class: Echinoidea
Genus: Echinus
Outer shell referred to as “test”. It is made of fused ossicles. IT is divided into amblacral zones and inter-ambulacral zones, but these are not visible unless spines are removed
List the phylum, class, and genus of this species. What are the names of the zones indicated by A and B? How can you tell?
Phylum - Echinodermata
Class - Echinoidea
Species - Echinus
A - Ambulacral zone
B - Inter-ambulacral zone
Can tell because A contains tiny holes for bearing tube feet
Does Echinus have pedicellariae?
Yes, but they are so much shorter than spines that it is hard tosee them
What is the name of structure A? What purpose does it serve?
Called Aristotle’s Lantern. It covers mouth and pharynx, is heavily muscularized, and may have teeth. IT can be protruded from the mouth to scoop or scrape food (ex. algae)
What are the Sand dollars?
Dorso-ventrally flattened Echiniodes.
Describe the test of Sea urchins and sand dollars
Radial pattern, but may not have radial symmetry. Usually made of calcium carbonate. Homologous to the ossicles found in sea stars
Name the Phylum, Class, and genus of this organism. Describe its external anatomy. What is the purpose of the spines?Where do the tube feet emerge? Where is the anus located?
Phylum - Echinodermata
Class - Echinoidea
Genus - Dendraster
Sand dollars have a test much like sea urchins, but it is covered in velvety spines that are in turn covered in cilia.
Spines + cilia allow the sand dollar to move across and burrow into sand.
Tube feet emerge from the petal-like areas as well as lines along oral surface.
Anus located on the bottom (on oral surface), near the back of the body.
Name the phylum, class of this organism. Name the structures indicated.
Phylum - Echinodermata
Class - Echnoidea
A - Madreporite
B - Ambulacral zone
C - Mouth
Name the phylum, class, and genus of this organism. Describe the external anatomy. What kind of skeletal elements does it possess?
Phylum - Echinodermata
Class - Holothuroidea
Genus - Cucumaria
Some tube feet modified to be tentacles on anterior end, other run up side of the body. Elongated body. Ossicles highly reduced (microscopic), spines small and contained within skin.
Name the phylum, class, and genus of this organism. Name the structures indicated. Why is this organism considered related to Sea Stars or Sea Urchins?
Phylum - Echinodermata
Class - Holothuroidea
Genus - Cucumaria
A - TUBE FEET
Still has tube feet (used for respiration) and awater vascular system
