Exam Questions and CORRECT Answers
A giant earthworm - CORRECT ANSWER - The picture of Roelke in a Rwandan cloud
forest shows him holding?
Phylum Annelida, Echiura, and Sipuncula - CORRECT ANSWER - -Coelomate
protostomes; coelom through schizocoely
-Spiral mosaic cleavage
Phylum Annelida - CORRECT ANSWER - -Latin "anneulus= little ring"
-Earthworms, leeches, polychaete worms
-Divided into segments called *metameres*
-Rings called *annuli*
-Some have chitinous bristles called *setae*
-Worldwide, nearly all habitats
Annelid Characteristics - CORRECT ANSWER - -Unique head, parapodia ancestral
-Bilateral symmetry, triploblastic
-Epithelium secretes moist cuticle
,-Digestive system complete and not segmented
-Asexual reproduction by fission & fragmentation
-Typically a pair of kidney like organs per segment for waste removal
-Closed circulatory system
Annelid Basic Body Plan - CORRECT ANSWER - -Usually a 2 part head: *prostomium
& peristomium*
-Terminal portion called a *pygidium*
-New segments just in front of the pygidium (older segments at the front)
-Each segment usually with its own circulatory, respiratory, nervous, and excretory structures
-Except for leeches, coelom filled with fluid to make a hydrostatic skeleton
Class Polychaeta (Phylum Annelida) - CORRECT ANSWER - -Greek "polys= many and
chaite= long hair"
-"Bristle worms"
-Most marine, up to 3m (10ft) long
-live under rocks in crevices, shells, in sediment, a few planktonic
-Significant component of marine food chains
,Photo: Christmas Tree/ Feather Duster worm
Polychaete Form & Function pt.1 - CORRECT ANSWER - -Well differentiated head w/
good sense organs, paired parapodia on most segments
-Many setae
-Usually divided into sedentary and mobile forms
-*Prostomium sometimes retractile, holds eyes, tentacles, sensory palps*
-*Peristomium surrounds mouth, has setae, palps, and chitinous jaws in predatory forms*
Photos: Nereis, Fire worm w/ setae (venomous), and anatomy; jaws & mouth, EM of annelid,
and up close face (all look like monsters)
Video:sand worms caught with a stink bag of fish
can hide in live rock for aquariums and eat the fish but hard to remove since they bite you
Polychaete Form and Function pt.2 - CORRECT ANSWER - -Foregut, midgut, and
hindgut
-Mobile species scavengers or predators, sedentary species usually filter feeders
-*Parapodia and gills for gas exchange*, some small species just use diffusion across body wall
-*3 types of kidney depending on species: protonephridia, metanephridia, or mix*
-*nephrostome* opens into coelom
, -Double ventral nerve cord
-Posses eyes, statocysts, nuchal organs; everything from simple eyespots to eyes with good
visual acuity & complicated structures (lens & cornea); *nuchal pits chemoreceptive*
-Usually no permanent sex organs, usually separate sexes; *gonads temporary swelling, gametes
shed into coelom, fertilization external, trochophore larvae*
Nereis (Representative Polychaete) - CORRECT ANSWER - -Clam or sand worms
-Predators
-Live in mucus lined burrows in sediment; come out at night to hunt: feed on small animals,
seize food w/ jaws, food swallowed as worms withdraws pharynx
-Creeps along, but can swim quickly by *undulation*
Our specimen in lab come from Atlantic tide pools
Scale Worms (Rep. Polychaete) - CORRECT ANSWER - -Very diverse & abundant
-Flattened bodies
-Carnivorous; predatory
-Most *commensal*, live in burrows of other polychaete or with cnidarians, molluscs, or
echinoderms