PHYLUM ANNELIDA

1
PHYLUM ANNELIDA

• SEGMENTED WORMS
• LITTLE RINGS

2
ANNELIDS

• PROTOSTOME
• COELOMATE
• BODY SEGMENTED WITH INTERNAL SEPTA
• HYDROSTATIC SKELETON
• LONGITUDINAL AND CIRCULAR MUSCLES

3
ANNELIDS

• SETAE / PARAPODIA
• BILATERAL SYMMETRY
• HIGHLY SPECIALIZED DIGESTIVE TUBE
• RESPIRATION-DIFFUSION THROUGH SKIN
• BRAIN W/ VENTRAL NERVE CORD

4
coelomic chambers
pharynx
mouth
esophagus
crop (storage)
gizzard (mashing)
5
brain
nerve cord
6
ANNELIDS

• CLOSED CIRCULATION
• AORTIC ARCHES FUNCTION AS HEARTS
• DORSAL AND VENTRAL BLOOD VESSELS
• NEPHRIDIA - 1 PR / SEGMENT
• HERMAPHRODITES W/ CROSS FERTILIZATION

7
hearts
blood vessels
8
ANNELIDS

• POLYCHAETA - MARINE
• SANDWORM OR CLAMWORM
• OBVIOUS CEPHALIZATION
• SETAE ON PARAPODIA

9
ANNELIDS

• HIRUDINEA - FRESHWATER
• LEECH
• ECTOPARASITE
• ANTERIOR AND POSTERIOR SUCKERS
• PARAPODIA AND SETAE ABSENT
• MEDICINAL USES

10
ANNELIDS

• OLIGOCHAETA - TERRESTRIAL
• EARTHWORM
• SETAE PRESENT, PARAPODIA ABSENT
• HEAD LESS DISTINCT
• BURROW THROUGH SOIL
• DETRIVORE FEEDING HABITS
• PROSTOMIUM OVER MOUTH
• CLITELLUM

11
EVOLUTIONARY MILESTONE

• SEGMENTATION

12
Arthropods
segmented body
Annelids
mouth
coelom
Mollusks
Roundworms
anus
head
false coelom
complete digestive system
bilateral symmetry, cephalization
unsegmented body
Flatworms
no coelom
mouth
radial symmetry, no cephalization
saclike gut
Cnidarians