Midterm sheet 2 Flashcards
(62 cards)
What is the rynchocoel
a tubular cavity that holds the introverted proboscis of a nemertean worm and is sometimes considered homologous with the coelom
How do nemertean’s capture prey?
- They shoot off its mouth to capture prey. They have eversible proboscis at the front end of the body.
how might you distinguish a
nemertean from a platyhelminth?
- Ribbon worms have a complete gut and circulatory system
- Flatworms are acoelomate
- Flatworms have cilia
- Ribbon worms have cuticle
- Flatworms glide
- Ribbon worms have longitudinal muscles
what is a radula, how does it work?
Tongue like structure of tiny teeth used to scrap food particles off surface and bring them to the mouth.
know the shell layers, and what
comprises them.
- Periosteum (uncalcified) the outer organic layer
- Prismatic layer (calcified)
- Nacre (Calcified) inner pearly layer of nacre
What are the types of coiling in
gastropods?
Planospiral, conispiral, dextral vs. sinistral
what is torsion
rotation of the visceral mass mantle and shell 180 degrees with respect to the head and foot of gastropod
how does respiration work in
gastropods?
air is brought in through a pneumostome (opening in the right side of the mantle) in pulmonates (have pallial lung instead of a gill or gills
how does feeding work in bivalves?
Detritivore (eat organic matter), the labial palps secrete a mucous that entangles suspended food and nutrient particles within the water to produce a bolus. Cilia in palps direct bolus to mouth
what does the term “bivalve” mean?
an aquatic mollusk that has a compressed body enclosed within a hinged shell
how do pearls form?
an intruder such as a grain of sand slips in between one of the two shells of the oyster and the mantle. Oyster will quickly begin covering the intruder with layers of nacre (mother-of-pearl) and coat the intruder
how does respiration work in
bivalves?
Ctenidium is shaped like a comb or feather and hangs into the mantle cavity and increases the area available for gas exchange
what is the circulatory system like in
bivalves?
open, filled with hemolymph, no separation, 1 fluid
how does the Nautilus maintain its
buoyancy?
The shell is for buoyancy, chambers filled with gas or cameral fluid and alter amount
how do cephalopods feed?
- Arms, tentacles, suction cups
- jaws and radula
- coordinated wave moment
what is the circulatory system like in
cephalopods?
Closed, three hearts (branchial pumps to gills or systemic pump to tissues)
what is the difference in arms and
tentacles?
tentacles are used to catch prey, covered in suckers and reproduction. arms are for grasping and locomotion
how does reproduction work in
cephalopods?
intenral fertilization, intrommittent, structure in males, modified arms called hectocotylus, dioecious
what are the benefits of
metamerism?
more efficient movement, can take multiple segments and natural selection will act on them (tagmatization), redundancy
what phyla possess metamerism?
annelida
what is an atoke? epitoke?
atoke is sexually immature, epitoke is sexually mature
what are siboglinids?
beard worms
what would you see if you opened
up a siboglinid?
cephalic tube has ciliated tentacles, glandular forepart that secretes the tube, trunk bears various annuli, papillae and ciliary tracts, metamerically segmented opisthoma
what are the basic characteristics of
a trochophore?
Ring of cilia, prototroch, sensory plate, tuft of cilia, ocellus (simple eye), mouth, stomach, anus, solenocyte
