20 polychaete Flashcards
majority of annelids once belonged to what class?
polychaeta
polychaeta is a term of
conveinence
what does the term polychaeta imply
presence of many chaetaew
where is most of the anatomical diversity on polychaetes
head and parapodia
what does prostomium contain
tentacles, palp, and sense organs like eyes
what surrounds mouth
peristomium
what is eversible in polychaete, and hwat does it have?
pharynx is eversible, has jaws
parapodia parts
notopodium- dorsal lobe
neuropodium- ventral one
-many chatae
-acicula(supporting chaetae)
what are parapodia for?
locomotion and gas exchange
how do polychaetes move?
crawling, swimming, burrowing, are sedentary
how do polychaetes move?(motion)
-longitudinal muscles alternately contract and relax in opposing sunchrony
-produces waves from posterior to anterior
-parapodia on opposite sides are exactly out of phase
what happens in recovery stroke
parapodia and chaetae retract in wave throughs.
what happens in ppower stroke
-parapodia and chaetae are extended m,aximally in power stroke as they pass along the crest of wave
in slow crawling
higher number of undulations
short wavelength
low amplitude
fast crawling
greater length and amplitude of undulation, but fewer
swimming
what type of polychaetes are efficient at this
wavelength and amplitude are greatest, however sometimes this can cause animal to go in reverse
-pelagic polychaetes are efficient
do polychaetes reproduce asexually
yes, they bud.
polychaete sexual reproduction
broadcast spawning of sperm and eggs
polychaete fertilization
external
polychaete sexes,when does sexual repro happen
seperate sexes, and gonads are temporary, only breeding seasons
what is a cool property of polychaetes
regenerationwhe
where are sperms and eggs released
nephridiopores or rupture of worms body
how do some polychaete gonads distance
epitoky
epitoky
part transforms into non beeding bag of gametes that swims away before exploding
which individuals are better equipped fir swimming
epitokous
what do individuals that reproduce during full moons have
larger eyes for light detection
what do polychaetes with external fertilizatoin have
trochophore larva
polychaete trochophore larva are
plankotrophic, meaning they feed
drooded polychaete larva exhibit
lecithotrophy
how does transformation into juveniles take place oin polychaetes
several segmented larval stages
errantia vs sedentaria polychaetes
errantia are active and often predatory
sedentaria are sedentary or sessile and particle feeders that burrow/ tube live
what clade does sedentaria include
clitellata
how do polychaetes catch prey
every pharynx armed with jaws
polychaetes whattype of feeding
suspension feeding and deposit feeding
chaetopterus
makes mucus bag that filters out particles
deposit feeding
1) general ingestrion of sediments
2) sort through via feeding appendages and seectively eat
what do selective deposit feeders normally have
palps subdevided into dozens of sticky tentacles
what is common among sedentaria with tubes
deposit and suspension feeding
tubes of sedentaria are made of
calcareous or made of mucus
siphuncula
penut worms
taxa in polychaetes
num spp of siphuncula
150
what do sipuncula lack
chaetae, circ syst, evidence of segmentation
what do sipuncula have two of?
eucoelomic cevities
what type of gut to sipuncula have
u shaped
how do sipuncula feed
deposit feeding
thalassematidae
clade within polychaetes
thalassematidae features
lack segmentation
one pair of ctenidia
thalassematidae larva features
segmented nervous system in larvae and juveniles
how do thalassematidae feed
deposit feeding
thalassematidae how many spp
220
two distinctive parts of thalassematidae body
trunk and proboscis
what do thalassematidae exibit in sexuality
sexual dimorphosm
sexual dimorphism
one sex waaaaay larger than other
siboglinidae
taxa in polychaeta
siboglinidae spp
180
siboglinidae habitat
hydrothermal vents, methane seeps, whale carcasses
body regions of siboglinidae
has 3, first w tentacles
last with segmented opisthosoma
gut in siboglinidae
lack gut, rely on symbiotic bacteria in tentacles or internal trophosome
what does the boneworm eat
bones, with the help of symbiotic bacteria
