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Annulus = ring
The nearly 1200 species comprising the
phylum Annelida are vermiform.
These animals are soft bodies,
The bodies consist of a series of repeating
segments.
The serial repetition of segments is known as
metamerism.
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The Annelid outer body wall is generally
flexible and can play an active role in
locomotion.
The thin body wall can serve as a general
surface for gas excange.
The cuticle remains permeable to both water
and gases (annelids are restiricted to moist
environment).
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Annelids segments are generally separated
from each other to large degree by septa.
Although some wastes are excreted across
the general body surface, excretion generally
occurs by means os structure called nephridia
This type nephridium is called a
metanephridium.
Annelids distributed among three classes:
Oligochaeta, Polychaeta and Hirudinea.
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Approximatelly 3,500 species are described
Only 6,5% are marine, most are found in
freshwater or terrestrial habitats.
This organism become widely used as a
biomonitor pollution stress.
Have few cetae without parapodia.
The prostoium have no eyes and tentacles.
Gas exchange is accomplisged by diffusion
across a body wall.
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Earthworms bury decomposing plant material
from the surface, which builds organic
constituent of soils.
• Burrowing aerates the soil and improves
drainage.
• "It may be doubted whether there are many
other animals which have played so important
a part in the history of the world as have these
lowly organised creatures.“ Charles Darwin,
1881
• “…the intestines of the earth…” Aristotle
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Cindy Hale, forest ecologist at Natural Resources Research
Institute at the University of Minnesota-Duluth
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Cindy Hale, forest ecologist at Natural Resources Research
Institute at the University of Minnesota-Duluth
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Gippsland area of Victoria, Australia. Up to 13
feet (4 meters) in length. Rapid movement in
the burrows is accompanied by a distinct
gurgling sound. Endangered.
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Anterior ¼-1/3 contains the differentiated portions
of the digestive tract and the reproductive organs
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Closed circulatory system
Separation of coelomic fluid and blood. This
figure shows capillaries associated with
nephridia, presumably for secretory exchanges
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Chloragogue tissue
surrounds gut and major blood-vessels “liverlike” in synthesizing fat and glycogen
Pheretima
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Complex head, followed by repetitive body
segments.
Segments usually have appendages called
parapodia
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Pharynx of some polychaetes is eversible
and has mineralized jaws
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Ventral view of a polychaete head with jaws
visible within the pharynx.
 • Errantia- the errant polychaetes
are active predators, such as Nereis
 • Sedentaria- the sedentary
polychaetes are tubicolous or
burrowing forms
Fan worm
Acrocircus
Choelia
Portula
Deposit feeders tentacles and
mucociliary mechanisms to gather
small particles from the substrate
 • Suspension feeders- ciliated
tentacular fans or mucus nets in
ventilated burrows to filter food
from the water.
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Tubicolous suspension feeders
Sabellids- “feather-duster” worms with
crowns of tentacles, tubes constructed of
mucus and detritus
Serpulids- tentacles like sabellids, but hard
calcareous secreted tube, sometimes spiral
Many have sexual stage called an
epitoke that is morphologically and
behaviorally specialized for sexual
reproduction
 The epitoke may be produced by
metamorphosis, or it may be produced
by longitudinal fission (budding).
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Eunice viridis, Fiji and Samoa. “Explosive”
spawning 1-3 nights each year, usually 7th night
after the first full moon following autumnal
equinox (siang malam waktunya sama).
 Epitokes swims to surface, millions burst/pecah
in unison, forming a slurry of eggs and sperm
 Local people feast on the raw worms.
 Marks the first day of the traditional Samoan
year
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A spider crab crawling through a colony of
Lamellibrachia sp. Tubeworms.
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Carnivorous, with oral and caudal
suckers used for locomotion and feeding
Not all are bloodsuckers- freshwater leeches
that prey on invertebrates are more diverse
and common than blood-feeders
There are few marine leeches- they are
mainly ectoparasites on fishes, including
sharks
Use in medicine for bloodletting
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In one clade, the females carry the egg
cocoon and the juveniles on their ventral
body surface.
Includes common Placobdella (turtle leeches)
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Medical use in blood-letting
Source of useful proteins, esp. anticoagulants
Model system for neurobiologylarge,
identifiable neurons, simple motor patterns
Popular sport-fishing bait
1. Anesthetic
2. Vasodilator (histamine-like)
3. Antibiotic properties, useful in the treatment
of glaucoma.
 4. Anticoagulants/antiproteolytics
• hirudin, inhibits thrombin (which activates
fibrinogen), bdellin, inhibitor of trypsin,
plasmin and acrosin, eglin- potent inhibitor
of elastase, cathepsin G, chymotrypsin and
subtilisin- blocks inflammatory response
• Decorsin- inhibits platelet aggregation
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hirudine
Haemadipsa/Pacet
Haemadipsa