BIOL 112 Phylum Annelida

Annelid

segmented worm

Annelid characteristics

Bilateral symmetry Triploblastic Cephalization Protostome Metamerism

Annelid Body Systems

Nervous system Digestive system Gas exchange Circulatory system Excretory system Reproductive system

Protostome

"Mouth First" mouth forms from blastopore

Coelomate

true body cavity tissue from mesoderm lines entire body cavity Has 2 main functions: 1.cushions internal organs

Hydrostatic Skeleton

coelom is filled with fluid

Metamerism

division of body into segments that are similar in structure

Central Nervous System

brain/ganglia and ventral nerve cord

Digestive System

complete digestive tract with separate mouth and anus multilayered intestine - includes muscle

typhlosole

infolding of intestine

Gas Exchange

Breathing in oxygen through skin and releasing carbon dioxide (terrestrial) or gills (aquatic)

Circulatory System

closed circulatory system - blood fully enclosed within blood vessels

Excretory System

body segments contain organs called nephridia (kidneys) that filter and remove nitrogen waste in liquid form

Reproduction

Hermaphroditic Male genital pore

Polychaetes

-found in shallow and deep water -common

polychaete anatomy

prostomium (1st body segment) - has a pair of antennae

Leeches

mostly freshwater feed mostly on blood of animals or whole animals

Leech anatomy

•anterior sucker (often with jaws and teeth) and posterior sucker for attachment •saliva has adaptations for predatory lifestyle •have a huge crop (food storage organ) for blood •have a reduced coelom because so muscular

Oligochaetes

earthworms and other freshwater worms

oligochaete locomotion

have two sets of muscles for movement: circular and longitudinal

Vas deferens/Male Genital Pore

release sperm

oviducts/ovipores

release eggs

Clitellum

secretes mucus to house fertilized eggs

Septa

walls that divide coelom into compartments

mouth

takes in food

Pharynx

suction

esophagus

food passes through

Crop

temporary food storage

gizzard

grinds food

ovaries

produce eggs and release them via the oviducts

seminal vesicles

produce and release sperm via the vas deferens

seminal receptacles

receive and store sperm from the other worm