Midterm sheet 2 Flashcards
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
how do echiurans feed?
Spoon worms; mucous net created with its proboscis, filters water through its burrow and traps planktonic organisms in this net
where might you find a sipunculan?
peanut worms; burrow in sand and mud or in rocks and empty shells in shallow waters
how are sipunculan larvae different
from other annelids?
cosmopolitan species, geographically widespread
what is wrong with the polychaetes
as a group?
they are paraphyletic
where do oligochaetes get their
name?
fewer setae
what is a clitellum? what is it used
for?
A raised band around the body that stores eggs and sperms
how do leaches feed?
have an anaesthetic and anticoagulant, has blood meals from a host
how do earthworms reproduce?
gonands appear and disappear, fertilization is external via clitellum
how do clitellata exchange gasses?
epithelial gas exchange basic life
know the basic life cycle of a cycliophoran.
complete life cycle internal and external budding, asexual and sexual, sessile and motile, feeding stage and prometheus larva
where would you find a
cycliophoran?
In water
know some of the basic differences
between entoprocts and ectoprocts
entoprocts are pseducoelomates, have anus inside tentacles
ectoprots are eucoelomate
what is a lophophore?
horseshoe shaped structure with ciliated tentacles around the mouth
in what ways are brachiopods
different from bivalve molluscs?
dorsal and ventral bivalve, feed with lophophore arms
what type of body cavity to
nematodes possess?
pseudocoelomate, hydrostatic skeleton
what is the cuticle of nematodes
made of?
non-cellular collagen cuticle secreted by hypodermis
how do nematodes move?
longitudinal muscles
how is the nervous system of
nematodes set up?
dorsal and ventral nerve cords
how does food move through the
digestive tract of nematodes?
no muscles so food moves when worm moves, enzymes that aid digestion
ascarids
poor water sanitation consume intestinal products go through wall to lungs to be coughed out.
- parasitic nematodes
trichiniella
muscle parasite, undercooked pork
- parasitic nematodes
filarial roundworms
parasitic, spread by flies, causes elephantiasis and heart worms, arthropod is their immediate host, tetrapod their definitive host
- - parasitic nematodes
pinworms
most common parasites
mermithid nematodes
free living larvae, infect arthropods, infect by drinking water or eating, kills host
how are nematomorph similar to mermithid
free living, parasitic to arthropods
what are the caudal appendages of
priapulids probably used for?
embryonic tail
what characteristic is shared by the
ecdysozoans?
grow by ecdysis, most have exoskeleton
what are the scalids of kinorhynchans
used for?
circlets and longitudinal rows of spines on the prostrusible cone shape head and neck
where might you encounter a
loriciferan?
Mediterranean sea, oxygen free environment
why is the “ladder” model for thinking
about evolution misleading and
wrong?
not a linear process
how do onychophorans feed?
fluid feeders, jaw inject digestive enzymes, oral papilla shoot protenaceus glue, branching slime glands
what characteristics do
onychophorans share with
arthropods?
chitinous culticle, pair of antennae
what are oral papillae used for?
excretion of slime glands, eating
in what ways are the tardigrades
similar to arthropods?
Chitinous cuticle, limbs, head and body segments, brain is similar
how do tardigrades feed?
fluid feeders, mouth with stylets pierce organism
where might you find a tardigrade?
moss, fern, soil, beaches, dunes, damp habitats
how does mating occur in
tardigrades?
parthenogenesis, resting eggs, anhydrobiotic eggs
what is a tun?
addition to dealing with water loss
