Annelida

Question 1

Generalized Body Plan (innovations)

7

Answer 1

Gut with 2 openings
Metamerism
Eucoelomic compartments & gut musculature
Blood vascular system
Metanephridia
Nervous system (dorsal brain & ganglionated ventral nerve cord)
Chaetae/setae

Question 2

Functions of Coelomic Compartments (4)

Answer 2

Circulation of nutrients & gases (ciliated mesothelium & epitheliomuscle in dorsal blood vessel)
Hydrostatic skeleton (metameres facilitate pressure differentials)
Role in excretion & osmoregulation (ultra-filtration via mesothelium of the dorsal blood vessel, selective reabsorption via metanephridium)
Storage of gametes (mesothelium generates gametes and eucoelom stores gametes)

Question 3

Nervous System

Answer 3

Dorsal prostomium with cerebral ganglia and paired ventral nerve cords
Subesophageal ganglia in each metamere

Question 4

Errantia Characteristics

Answer 4

Active lifestyle (active burrowing, surface crawling, swimming)
Marine
Well developed, similar parapodia on most metameres
Eversible, armed pharynx
Head appendages for sensory reception

Question 5

Glyceridae (blood-worms)

Answer 5

active burrowers

Eversible well-armed pharynx with 4 jaws each with venom gland

Question 6

Sedentaria Characteristics (6)

Answer 6

Sedentary or sessile lifestyle
Live in permanent burrows or secreted tubes
Parapodia often reduced
Parapodia often show regional specialization
Pharynx may be reversible but never armed
Elaborate head appendages, if present used for feeding

Question 7

Arenicolidae (lug worms)

Answer 7

Sedentary
Use a sticky eversible pharynx to deposit feed
Dig anterior end into the hole and draw water into it via posterior end

Question 8

Sabellidae (feather duster worms)

Answer 8

Sessile
Secrete, proteinaceous tubes
Suspension feeders with radioles
Anterior parapodia for crawling up and down tube

Question 9

Terebellidae (spaghetti worms)

Answer 9

Surface deposit-feeding
Form tubes of sand glued together
Ciliated feeding tentacles and reduced parapodia

Question 10

Siboglinidae (hot-vent worms)

Answer 10

Symbiotic sulphide-oxidizing bacteria

The first discovery of ecosystem with geothermal energy as the basis

Question 11

Echiuridae

Answer 11

Adults show no evidence of metamerism
Pair of setae, prostomium and trunk
Show some metamerism in larval stages

Question 12

Reproduction Marine Annelids

Answer 12

Dioecious
Gametes from mesothelium and stored in coelomic compartments
Broadcast spawn – gametes escape via coelomoducts or metanephridia
External fertilization in seawater
Trocophore larva

Question 13

Epitoky

Answer 13

Morphological transformation into sexual individual

Large eyes, enlarged parapodia as swimming paddles, ripe gametes in coelomic compartments, regression of gut

Question 14

Clitellata Characteristics

Answer 14

No parapodia
Hermaphroditic – complex reproductive system
Clitellum

Question 15

Oligochaeta

Answer 15

No parapodia, but do have chaetae
Regional differentiation along the length of oligochaete digestive tract
Chlorogogen tissue
Hermaphroditic, pseudicopulation, important role of clitellum

Question 16

Chlorogogen Tissue

Answer 16

Specialized mesothelial cells

Intermediary metabolism: glycogen & fat synthesis & storage, hemoglobin synthesis, protein catabolism & urea synthesis

Question 17

Hirudinea

Answer 17

No chaetae
Anterior & posterior suckers 
Dorso-ventrally flattened 
Specialized features for ectoparasitism 
Dorso-ventral undulation
Bladelike thickening of the cuticle 
Hirudin and anesthetic