Phyla Study Guide Flashcards
Synapomorphies of Hemichordata
Stomochord - flexible, hollow tube (possible homologue to nerve chord)
No brain or prospects (nerve net and longitudinal nerves)
3 distinct segments - anterior prosome (proboscis)
intermediate collar (dorsal neural tube, nerve network)
posterior trunk (digestive tract, gonads, stalk, gill slits)
What is the Enteropneust larval form called? (Hemichordata)
Tornaria larva
What is the function of the Hemichordata proboscis?
it’s muscular and ciliated, making it the primary contributor of movement, but also helps in collection and transportation of food particles and burrowing
What makes nematodes pseudocoelomates?
they have a false coelom, and their endoderm is disconnected from their mesoderm
What is a stylet and how is it used in nematodes?
a hollow feeding structure inserted into prey (plant or animal) to suck nutrients out or inject digestive enzymes. used by parasitic organisms
How do nematodes acquire and digest their food?
food enters through the mouth and goes through Peristalsis, where the mesoderm (muscular layer) contracts and squeezes the endoderm, pushing food through the digestive tract
How do xenacoelomorphs move?
They have fully ciliated bodies that aid in locomotion
How do xenacoelomorphs reproduce?
They are hermaphrodites that are capable of sexual or asexual reproduction. They can brood or encapsulate their eggs. Direct development, regeneration.
How do acoels from xenacoelomorpha feed?
can use eversible pharynx, those without a pharynx form a sphincter around the mouth using muscle fibers. they have a syncitial gut. larger prey are coated in mucus and slowly moved towards the mouth via epidermal cilia
how do nemertodermatids from xenacoelomorpha feed?
they use a cone of gut tissues to function as a tongue and grab food, some even have an eversible proboscis called the “broom organ”, and they have a well-defined lumen rather than a syncitial gut
how do xenoturbellids from xenacoelomorpha feed?
they open their mouth and protrude their unciliated foregut
synapomorphies of xenacoelomorpha
bilateral symmetry, acoelomate body plan, xenacoelomorphan ciliated epidermis, midventral mouth, incomplete digestive system without an anus, direct development
What xenacoelomorphan species can fully regenerate and what class are they from?
symsagittifera roscoffensis (mint-sauce worm), acoela
What genus is parasitic in holothuroid guts?
Meara stichopi
synapomorphies of sipuncula
unsegmented coelomates, soft-bodied (separated by sac-like trunk and retractable introvert, introvert bears a mouth with an array of tentacles at distal end), pair of nephridia (maintain osmoregulation and have reproductive uses), unpaired nerve cord
how do sipuncula feed?
mostly deposit feeders, use tentacles to eat food particles from sediment, those on hard surfaces use introvert hooks to scrape off sediment
how do sipuncula reproduce?
most are dioecious (separate male and female reproductive organs), gonads release gametes into the coelom where they mature before being released into the water column by nephridium
What is the purpose of the nephridium in sipuncula?
maintains osmoregulation and releases fully developed gametes into the water column
What are the larval forms of peanut worms?
pelagosphera and trochophore
What is the nuchal organ in sipuncula and what is it used for?
a ciliated pit structure used for light and food detection as well as finding mates (found in class phascolosomatidea)
what genus of peanut worms are suspension feeders?
themiste
what are the 2 classes of sipuncula and what are the main differences?
sipunculoidea and phascolosomatidea, sipunculoidea doesn’t have a nuchal organ
synapomorphies of phoronida
3 body parts each with coelomic cavity (epistome - overhang on mouth, mesosome - lophophore and regenerative mass of specialized tentacles used for feeding and respiration, metasome - trunk), lophophore, no valves, ampulla (bulbous mass at end of trunk), nerve ring, bilateral symmetry, closed circulatory system
how do phoronids feed?
ciliated tentacles move water towards the oral ring with food particles trapped in mucus. once it reaches the mouth food is drawn in and moved to the digestive tract
how do phoronids reproduce?
sexual reproduction, mostly hermaphroditic, eggs or larva brooded in body cavity until secreted,
What are the 2 different types of reproduction in horseshoe worms?
phoronis ovalis lay only a few eggs with lots of yolk that are brooded until secreted, the larva do not feed, the larva sink to the ocean floor and then permanently attach to a substrate where they develop into an adult
phoronis australis lay a large number of small eggs that are released directly after fertilization and hatch into actinotrocha larva, they sink to the ocean floor, develop into a benthic adult, and attach to a substrate
What do horseshoe worms use the lophophore for?
the lophophore is a u-shaped organ used for feeding
What differentiates phoronopsis from phoronis?
phoronopsis has a collar fold under the lophophore
mucous house in appendicularia
series of filters, chambers, channels, funnels, and valves that protects the animal and keeps it afloat
how do appendicularians reproduce?
sexual reproduction, mostly hermaphrodites (minus oikopleuradioica), release sperm, eggs burst out of body wall
how do appendicularians move?
the tail generates undulations to pump water through the tail chamber
what is the most well-known family in class appendicularia?
oikopleuridae
what is the house used for in appendicularia?
protects the animal and keeps it afloat
what are the synapomorphies in appendiculara?
gill slits, tubular nerve cord, rod-like notochord, and a post-anal tail
What is an easy way to tell the difference between a branchiopod and a bivalve?
branchiopods have bilateral symmetry
What is the primary structure used for feeding?
lophophore, feeding filter with cilia in the filaments that draw in water currents to provide food
What is the most common subphylum of branchiopoda?
linguliformea
what are the larval forms of branchiopods?
rhynchonelliformea, craniiform, linguliform
What are the synapomorphies of chaetognatha?
bilateral symmetry, retractable chitinous jaws, multilayered epithelium on body, cephalic hoods, retrocerebral organ (organ above and behind the brain), ciliary loop, no lungs
How do arrow worms feed?
ambush feeders that sense water movement to detect prey before grabbing pray using grapsing hooks
How does chaetognatha reproduce?
hermaphroditic, direct development, internal fertilization
What technological advances are being used to re-define classification of chaetognatha?
genetic testing and examination is being done
Synapomorphies of nemerteans
proboscis, rynchocoel (tubular cavity that holds the proboscis), ganglion
What makes malacobdella grossa different from other nemerteans?
they have a commensal relationship with mollusks
How does class anopla differ from class enopla in nemerteans?
anopla has separate mouth and proboscis openings and enopla has a single opening for both
what are the larval forms in nemertea?
planuliform and pilidium
5 synapomorphies of thaliacea
notochord (flexible supporting rod with muscle attachment), dorsal hollow nerve cord (nerve chord that runs along dorsal surface), endostyle or thyroid (mucus-covered structure in the pharynx used for filter feeding), pharyngeal slits (openings into pharynx for filter feeding), post-anal tail (tail that extends beyond the atrail/anal opening)
how does thaliacea feed?
non selective and filter feeding (pump water through body, in through mouth and out through atrium opening)
how does thaliacea reproduce?
asexual reproduction, budding occurs from the endostyle stolon
what phylum does Pyrostremma Spinosum belong?
thaliacea
What is the difference between the notochord and the dorsal hollow nerve chord in thaliacea?
notochord is lost in adults while the dorsal hollow nerve chord can be seen in adults
what does non-selective feeding mean?
eat anything they can find
what are the feeding differences between the two classes of priapulids?
secticoronaria uses anterior scalids to form 2 tentacles and create a feeding trap
priapulida has no tentacles but a fully retractable proboscis
what are the synapomorphies of priapulida?
3 part body (introvert proboscis, trunk, caudal appendage), chitinous cuticle, bilateral symmetry
what is the dominant larval stage in priapulids?
loricate
what are the two parts of bryozoa structure?
cystid - outer casing
polypide - comprised of the lophophore and viscera
name 2 different means of reproduction in bryozoa
budding and fragmentation
how does the lophophore in Phylactolaemata differ from the other 2 classes in bryozoans?
they have a u-shaped lophophore
what is the function of the communication pore in bryozoans?
allows zooids to share nutrients and transmit chemical signals
synapomorphies of entoprocta
stalks, calyx, anus
how do entoprocta feed?
filter feeders, crown of ciliated tentacles creates a water current to draw food particles towards lophophore
platyhelminthes synapomorphies
acoelomates, bilateral symmetry, unsegmented and triploblastic, blind gut
how do platyhelminthes feed?
have intracellular and extracellular digestion, non parasitic organisms have an oral sucker around the mouth for feeding, those without a mouth absorb nutrients, herbivores can have a simple ciliated pore as a mouth while carnivores may have a pharynx
how do platyhelminthes reproduce?
hermaphroditic internal fertilization
