Bio 2 Lab- Animal Diversity (annelids) Flashcards

Annelid
Terms Definitions
prostomium
the anterior head region of adults (not considered a metamere)
peristomium
also considered the head region. just below the prostomium (not considered a metamere)
pygidium
the terminal "tip" bearing the anus (not considered a metamere)
segments are added...
newest segments are added at the posterior end
beardworms
have been added to the Polychaeta phylum

no digestive tract
Polychaete characteristics
bilobed parapodia and setae on each sement

exhibit epitoky
atoke
non-sexual form of part of a polychaete
epitoke
sexual part or form of a polychaete
filter -feeding tube worms
Polychaeta

beating of cilia on the pinnules of the radioles produce a current up and out
clitellum
wraps eggs in a cocoon, where eggs develop directly into small worms (oligochaeta)
the gut of oligochaeta
divided into:
pharynx
crop
gizzard
intestine
Hirudinea
have a clitellum only during reproduction

lack setae

no internal sepa

no circulatory system

have a fixed number of segments

secrete aneasthetics, antibotics, and anticoagulants
posterior sucker
attaches to the host
anterior sucker
sucks host's blood/boody fluids
Phylum Echiura
"spoonworms"

no sign of segmentation

constantly extended, spoom-shaped proboscis

dioecious

poorly studied..closed circ.sys
annelida
the segmented worm
nutrient redistribution
important for marine and terrestrial ecosystems (soil drainage and aeration as well)
coelom
a fluid filled body cavity COMPLETELY enclosed by mesoderm
metameres
repeating segments
metamerism
division of the body into distinct, serially repeated segments
annuli
separate metameres EXTERNALLY
septa
separate metameres INTERNALLY
circulation
closed system
dorsal vessel
pushes blood forward (anteriorly)
ventral vessel
moves blood posteriorly
capillary bed
connect the 2 major blood vessels in the body wall (where blood gets oxygenated) and in the gut wall ( where the blood picks up nutrients)
setae
chitinous bristles

(short, stiff setae anchor a segment in an earthworm and prevent slippage backwards)

(long setae help aquatic annelids swim)
movement
coelom serves a hydrostatic skeleton

circular and longitudinal muscles
parapodia
pair of setae "paddle-like appendages"
in marine polychaetes
aciculum
a chitinous rod in a parapodium with oblique muscles attached
peristalsis
similar movement in annelids

due to circular and longitudinal muscles
nervous system
ganglia and nerve branches are repeated in each segment
metanephridia tubules
in almost all segments

collect and filter coelomic fluid, removing nitrogenous wastes (urea in terrestrial species; ammonia in aquatic species)
gas exchange
via diffusion
nephridium
excretory tubule in each segment
earthworm typhlosole
U-shaped intestine increases surface area for absorption
oligochaetes reproduction
monoecious
hirudinea (leeches) reproduction
monoecious
polychaeta reproduction
dioecious
monoecious reproduction
either direct: young adult emerges
OR
indirect: a ciliated trochophore larval stage
(segments are added over time)
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