Annelida Flashcards
what are the three classes of annelida?
polychaeta (marine worms)
oligochaeta (earthworms)
hirundinea (leeches)
defining characteristics of annelida
- 1 or more pair of chitinoussetae/chaetae
- metamerism
- trochophore larvae (gr: wheel bearing)
biphasic lifestyle
broadcast spawner
metamerism
linear series of body segments
tagmata
a grouping of segments (arthropods)
what is the difference between metameric segmentation and tagmata?
linear vs grouping of segments
size range of annelida?
microscopic to 3m
what type of body cavity to annelida have?
coelomic
what type of circulatory system of annelida?
closed circulatory
where is the nerve cord located on annelida?
ventrally
excretion via what?
nephridia
vermiform
worm-shaped
what is the difference between setae and cilia?
setae: stiff bristles present on the body. aid in peristaltic motion.
cilia: minute hair like organelles that line the surfaces of certain cells and beat in rhythmic waves.
peristaltic movement
the movement by constricting part of its fluid filled body cavities, allowing for elongation of the body anteriorly. when relaxing the setae keeps the body from moving backwards.
describe polychaeta
marine worms: -tube worms -sand worms numerous setae well developed head -including sensory organs -antennae -able to secrete mucus in epithlium
describe the parapodia of polychaeta
paired, lateral, fleshy, paddle like.
what is different about polychaeta’s sex organs
they are not permanent. they shed gametes in breeding season via nephridia.
describe the spawning method of polychaeta
broadcast spawners.
- external fertilization
- through to a trochphore larvae
epitoky
polychaete mode of reproduction
-worms partially or entirely transform into an epitoke, a pelagic form able to reproduce. this is where gametes are produced
sedentia vs errantia
sedentia= sessile errantia = active
what two types of burrows do polychaete do?
simple vertical or U shaped
what do burrows serve as for polychaetes?
protective retreat.
- a lair for catching passing prey
- provide access to clean oxygenated water above a muddy or sandy bottom
describe the tubes of sedentia polychaetes
- made of secreted material from glands on the ventral surfaces
- permit the worm to inhabit hard, bare surfaces such as rock shell or coral
what type of sensory appendages are well developed in sendentia polychaeta?
- prostomial.
- 1st segment of a worm’s body in the anterior end
how do errant polychaeta move (using an anchor system)
eversible pharynx
-punch and anchor in the sediment, and upon retraction move themselves forwards
manners in which polychaeta burrow/move about
peristaltic burrowing
eversible pharynx
rapid lateral undulations (shimmy)
crawl with parapodia and body waves
Polynoidae is a ________ of polychaetes?
guest. lives in tubes and the burrows of other polychates and crustaceans on corals and the ambulacral grooves of sea stars. symbiotic.
Class hirudinea:
- where can you find them?
- how many segments?
- setae?
- what type of parasites?
- parapodia?
- marine, fw, terrestrial
- 32-34 segments
- generally ectoparasites
- no setae
- lack parapodia
how are hirudinea shaped?
dorsoventrally flattened, anteriorly tapered.
annulations external.
why is movement different for hirundea?
no septa between segments, reductions of coelom.
- inchworm like movement
- undulates like eels
where are the suckers located on hirudinea?
anterior and posterior
describe the reproduction type of hirudinea
- internal fertilization
- hermaphroditic
- anterior suckers grasp
- cocoon appears for egg laying
what country is big on medicinal leeches?
india
what species of leech is used for medicine?
Hirudo medicinalis
what would you use a medicinal leech for?
- anti-coagulants
- vasodilators (heart disease)
- plastic surgery
- reattachment of limbs
hirudin
anti-coagulant properties in Hirudo medicinalis.
what type of carnivore are hirudinea?
sanguivores
Oligochaeta are found in which environments?
mainly fw and terrestrial
oligochaeta
-parapodia
absent. instead simple setae
clitellum
a thickened glandular section of the body wall near the head that secretes a viscid sac in which eggs are deposited. Hirudinae + oligochaeta
oligochaeta:
- what type of reproduction?
- gonads?
- reproductive segments?
- hermaphrodites
- permanent gonads
- specific reproductive segment
how often do oligoghaetes breed?
semi continually
describe the feeding preferences of oligochaetes
- type of feeder
- what type of food do they feed on
- when do they ingest
- scavengers
- feed on vegetation and decomposing matter
- ingest while burrowing
