Annelids Overview

phylum annelida body structure

bilateral, triploblastic, metameric

phylum annelida coelom divided by

septa

phylum annelida coelom functions as

a hydrostatic skeleton (except in leeches)

phylum annelida muscles

outer circular and inner longitudinal

phylum annelida cuticle

transparent and moist

phylum annelida cuticle is secreted by

epithelium

phylum annelida digestive system

complete, non segmented

phylum annelida nerve cord

double ventral nerve cord

phylum annelida ganglia

segmented

phylum annelida cerebral ganglia

acts as brain

phylum annelida sensory organs

tactile organs, taste buds, statocysts, photoreceptors

phylum annelida asexual reproduction

fission and fragmentation

phylum annelida sexual reproduction

hermaphroditic/separate sexes

phylum annelida excretion

paired nephridia per segment

phylum annelida respiratory

through skin, gills, or parapodia

phylum annelida circulatory system

closed

metamerism

body divided into repeated segments with similar organs

polychaeta body plan

segments with many setae and parapodia for different functions

polychaeta diversity

predatory, deposit, filter feeding

polychaeta reproduction

dioecious, no clitellum

siboglinidae life

tube dwelling

siboglinidae lack

mouth and digestive tract

siboglinidae energy source

chemoautotrophic bacteria

echiura life

burrowing

echiura feeding

deposit feeding with a proboscis

echiura lack

segmentation

oligochaeta include

earthworms and freshwater annelides

oligochaeta setae and parapodia

few, none

oligochaeta clitellum for

cocoon formation

hirudinea include

leeches

hirudinea feeding

fluid

hirudinea clitellum

cocoon formation

siphunculans are

burrowing marine worms

siphunculans feeding

retractable proboscis

siphunculans lack

segmentation