PL_LESSON 4: PHYLUM ANNELIDA

PHYLUM ANNELIDA

“Segmented worms”

PHYLUM ANNELIDA

Marine, freshwater, and terrestrial

PHYLUM ANNELIDA

Free-living, symbiotic, or ecto-parasitic

PHYLUM ANNELIDA

Vermiform

Metamerism

segmentation

PHYLUM ANNELIDA

The coelom is well-developed

PHYLUM ANNELIDA

Muscular body walls (circular and longitudinal muscles)

circular muscle 

Surrounded by a muscular body wall. The outer wall

longitudinal muscles

inside

Setae

used for locomotion

parapodia

Hair structures on their ___(appendages found in each of their body segment, which they can also use for respiration)

PHYLUM ANNELIDA

• Respiration through the skin, gill, and the parapodia

PHYLUM ANNELIDA

Closed circulatory system

They have blood vessels and a heart

PHYLUM ANNELIDA

Hydrostatic skeleton

Hydrostatic skeleton

Allows to change shape but not its volume, which allows them to successfully crawl, swim, or burrow on the ground

PHYLUM ANNELIDA

Digestive system complete

PHYLUM ANNELIDA

They have a mouth and a pharynx

nephridia

The excretory system typically consists of a pair of ___(organs of excretion) per segment

asexual reproduction

Separate sexes or hermaphroditic individuals can also perform ____(fission or fragmentation)

Nereis sp.

Rag worms or clam worms

Nereis sp.

Lumbricus terrestris

Earthworm

Hirudo medicinalis

Leech

Lumbricus terrestris

Hirudo medicinalis

CLASS ERRANTIA

Known as Errant polychaetes/clamworms

CLASS ERRANTIA

Aquatic and can tolerate a wide range of environmental salinity

CLASS ERRANTIA

Well-differentiated head

CLASS ERRANTIA

Parapodia on most segments, with setae

CLASS ERRANTIA

Bears cirri (tentacles)

CLASS ERRANTIA

Found in the head or tail

Most are nocturnal

Have about 200 body segments and are capable of growing up to 30-40 cm in length

Notopodium

Dorsal lobe

Neuropodium

Ventral lobe

CLASS SEDENTARIA

Earthworms and leeches

CLASS SEDENTARIA

Order Clitellata

Family Lumbricidae

Genus Lumbricus

Species Lumbricus terrestris

CLASS SEDENTARIA

Order Gnathobdellida

Family Hirudinidae

Genus Hirudo

Speces Hirudo medicinalis

CLASS SEDENTARIA

Includes many species that live in tubes or burrow, or as ecto parasites

CLASS SEDENTARIA

Very slow movers or a sedentary lifestyle

CLASS SEDENTARIA

Unlike Class Errantia

But they have developed more cirri or tentacles or food capture

Parapodia

are often very small or they have lost them completely

ORDER CLITELLATA

Earthworms

ORDER CLITELLATA

Found in moist, rich soil

Mostly emerge at night to scavenge for food. On rainy days, they stay near the surface and expose parts of the body. When it is hot, they often burrow down deep and coiled themselves to remain normal

clitellum

ORDER CLITELLATA Bears' reproductive structure, called the

ORDER CLITELLATA

Well-developed layers of circular and longitudinal muscles for crawling - peristaltic waves of contraction

ORDER CLITELLATA

Divided internally into segments by septa

ORDER CLITELLATA

Lacks parapodia, but setae are present

ORDER CLITELLATA

Hermaphrodites

Monoecious

bears both male and female reproductive organs

Prostomium

contains the mouth

Clitellum

cocoon formation for reproduction

ORDER GNATHOBDELLIDA

Leeches

ORDER GNATHOBDELLIDA

Occur in freshwater habitats, a few are marine, and some have been found in warm, moist terrestrial habitats

ORDER GNATHOBDELLIDA

Carnivores or temporary/permanent parasites

ORDER GNATHOBDELLIDA

Lack setae completely

ORDER GNATHOBDELLIDA

Possess anterior and posterior suckers

ORDER GNATHOBDELLIDA

Dorsoventrally flattened

ORDER GNATHOBDELLIDA

Clitellum appears only during the breeding season