PHYLUM ANNELIDA

ANNELIDA=>ANNELIDA=>•“segmented worms”•often hermaphroditic•True coelom•Digestive tract

•“segmented worms”•often hermaphroditic•True coelom•Digestive tract

ANNELIDA=>ANNELIDA=>•most marine species in class:

Polychaeta•either free-swimming or

“fanworms”

•most marine species in class: Polychaeta

•either free-swimming or “fanworms”

ANNELIDA=>ANNELIDA=>• fanworms are tube-dwellers that

have tentacles for filter-feeding• fanworms are tube-dwellers that

have tentacles for filter-feeding

“Christmas Tree” worms“Christmas Tree” worms

ANNELIDA=>ANNELIDA=>•free-swimming annelids have a pair of parapodia on each segment

•usually powerful, pincherlike jaws: (sandworms & clamworms)

•free-swimming annelids have a pair of parapodia on each segment

•usually powerful, pincherlike jaws: (sandworms & clamworms)

ANNELIDA - “fireworm”ANNELIDA - “fireworm”

ANNELIDA - “clamworm”ANNELIDA - “clamworm”

The EARTHWORM:The EARTHWORM:•Class: Oligochaeta•Class: Oligochaeta

The EARTHWORM:The EARTHWORM:•MOVEMENT:

–1) posterior setae anchor–2) circular muscles contract–3) anterior setae anchor–4) circular muscles relax and longitudinal muscles contract

•MOVEMENT:–1) posterior setae anchor–2) circular muscles contract–3) anterior setae anchor–4) circular muscles relax and longitudinal muscles contract

• *muscles contract against “hydrostatic skeleton”

• *muscles contract against “hydrostatic skeleton”

The EARTHWORM:The EARTHWORM:•EXCRETION:

–NEPHRIDIA - long tubules that excrete liquid waste

•EXCRETION:–NEPHRIDIA - long tubules that excrete liquid waste

The EARTHWORM:The EARTHWORM:• DIGESTION:

– “MOUTH” (opening)– PHARYNX (acts as a soil pump)– CROP (temp. storage organ)– GIZZARD (grinds up soil)– INTESTINE (nutrients are absorbed)– ANUS (exit)

• DIGESTION:– “MOUTH” (opening)– PHARYNX (acts as a soil pump)– CROP (temp. storage organ)– GIZZARD (grinds up soil)– INTESTINE (nutrients are absorbed)– ANUS (exit)

The EARTHWORM:The EARTHWORM:

The EARTHWORM:The EARTHWORM:• RESPIRATION & CIRCULATION:

– no special resp. structures– breathe through moist skin– blood flows from anterior (ventral

blood vessel) to posterior (dorsal blood vessel)

– AORTIC ARCHES - 5 pairs of muscular vessels at ant. end “hearts”

• RESPIRATION & CIRCULATION:– no special resp. structures– breathe through moist skin– blood flows from anterior (ventral

blood vessel) to posterior (dorsal blood vessel)

– AORTIC ARCHES - 5 pairs of muscular vessels at ant. end “hearts”

The EARTHWORM:The EARTHWORM:

•RESPONSE:–small “brain” of fused GANGLIA–ventral nerve cord–poor sensory organs

•RESPONSE:–small “brain” of fused GANGLIA–ventral nerve cord–poor sensory organs

The EARTHWORM:The EARTHWORM:

•REPRODUCTION:–are hermaphrodites–cannot fertilize own eggs–young hatch in 2 - 3 weeks

•REPRODUCTION:–are hermaphrodites–cannot fertilize own eggs–young hatch in 2 - 3 weeks

LEECHES:LEECHES:•Class: Hirudinea

–have no setae nor parapodia–most are parasites–most dwell in fresh water

•Class: Hirudinea–have no setae nor parapodia–most are parasites–most dwell in fresh water

LEECHES:LEECHES:•Class: Hirudinea

– one pair suckers– muscular pharynx w/ razor-sharp

teeth– anti-coagulant & pain-numbing

saliva

•Class: Hirudinea– one pair suckers– muscular pharynx w/ razor-sharp

teeth– anti-coagulant & pain-numbing

saliva