what are the roles of parapodia?
- gas exchange (gills)
- movement (when supported with acicula)
- protection
- creating currents
describe an annelid’s nervous + sensory system
- each segment has 2 ganglia bundles
- has 2 ventral nerve cordc
- brain with eyes (cerebral ganglia)
what two phylogenic groups are within Clitellata (terrestrial and freshwater)?
Oligochaeta (earthworms) and Hirudenea (leeches)
how does Chaetopteridae feed?
- uses fin parapodia to create current inside tube
- current pulls water into tube from anterior end and organic matter into mucus bag
how does a metanephridium work?
1) ciliated funnel pulls coelomic fluid into coelom as primary urine
3) muscle contractions push primary urine through metanephridia
4) final urine exits through nephridiopores
what is inside an annelid segment?
- 2 metanephridia and a nephridiopore
- coelom
- blood vessels
- nerve cord
- peritoneum that compartmentalizes each segment
what are the differences between a protonephridium and a metanephridium?
proto:
- unicellular
- one opening (exterior)
- waste enters via flame cells
- fluid moved via cilia-generated currents
- contains a flame cell and flagella/cilia
- uses extracellular fluid as medium
meta:
- multicellular
- two openings (one to coelom one to exterior)
- waste enters via blood vessels
- fluid moved via muscular contractions
- uses coelomic fluid as medium
how do Echiurans feed?
- suspension and deposit feeding via mucus nets and proboscis that scoops and collects food
- adult burrows
what is the peristomium?
first segment behind prostomium
How does Siboglinidae feed?
- uses bacteria to collect material from hydrothermic vents
- chemoautotrophic
- no gut or mouth due to this
what families are under the class Sedentaria?
- Sabellidae (feathery mucus suspension)
- Echiura (no parapodia, chaetae, has single coelom)
- Capitellidae (surface deposit)
- Arenicolidea (subsurface deposit)
- Terebellidae (surface deposit)
- Siboglinidae (tubeworm, chemoautotroph, no mouth)
- Serpulidae (hard tubed suspension)
- Cirratulidae (organic tubed suspension)
- Spionidae (deposit + suspension)
how does Tomopteridae feed?
- uses elongated cirri and parapodia to swim and catch large prey in water column
what are acicula made of?
chitin
what are some features from Oligochaetes?
- no parapodia
- peristaltic movement
- gas exchange via skin
- pair of metanephridia at each segment
- no eyes
- simultaneous gamete exchange
- hermaphrodite
what similarities and differences do Cirratellidae and Serpulidae have?
- both suspension feeders using mucus net
- Cirratellidae = organic tubes, Serpulidae = calcified tubes
what are the body layers of annelids?
cuticle, epidermis, muscle, peritoneum (lines the coelom)
or
ectoderm, mesoderm, endoderm
how do Annelids move?
- sinusoidal motion (alternation of constricting and relaxing of R+L longitudinal muscles)
- peristaltic motion (alternation of constricting and relaxing circular muscles)
what feature defines Clitellata?
clitellum (banded reproductive organ)
how does Terebellidae feed?
- spaghetti worms
- bury trunk into sediment and uses tentacles/palps to reach out and grab food items
what is the pygidium?
terminal segment with anus
what are the three sections of annelids?
prostomium (head), trunk (body), pygidium (rear segment)
how would you describe the metameristic body plan annelids have?
repeating similarly shaped segments separated internally by septa (mesoderm)
how does Sipunculida feed?
- typically burrows
- anterior cilia plumage funnels food from surface
what characteristics do Clitellata have?
- reduction/loss of segments
- reduction of chaetae and parapodia
- specialization of segments
