Download Phylum: Annelida

Phylum: Annelida
• “ringed”, commonly called segmented worms
• Examples: earthworms, marine worms,
leeches
Traits
• Segmented, round, wormlike bodies
Traits
• Bilateral symmetry
Traits
• cephalized
Traits
• Ventral nerve cord
Traits
• Tube-in-a-tube digestive system with
specialized regions
Traits
• Closed circulatory system – blood doesn’t
leave the vessels
Traits
• Paired nephridia
Traits
• Respire through their skin
Typical invertebrates
• Earthworms are about halfway between the
simplest and most complex invertebrates
Classes
Oligochaeta
Polychaeta
Hirudinea
Oligochaeta
• “few bristles”, no parapodia
• E.g. – earthworms, tubifex worms
Benefits of Earthworms
• improves aeration
• increases water and nutrient movement
through the soil
• Castings are rich in nutrients
Usually feed on decaying organic matter
– can eat ½ -1 times their weight
• Charles Darwin went so far as to say of
earthworms, “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 organized
creatures.” He believed that earthworms are
wholly responsible for the top layer of rich soil
on the Earth
Earthworms vary in
size from a centimeter
to several meters long
Giant Gippsland
Earthworm in
Australia
Up to 15 feet stretched out!
Blue luminescent
earthworms in
Australia
• Striped
earthworm in
Australia just
discovered in
2007
Worm Farming
• Used for compost
• Sold for fishing bait
Tubifex Worms
Polychaeta
• “many bristles”, have parapodia,
largest class of annelids
• E.g. – marine worms, tube worms
Parapodia
• mainly used in respiration
Blood worm
Bristle worm
Venomous Setae
If touched, the setae will detach
and lodge in the skin causing
burning, itching, and numbness
from the toxins they contain
Tube Worms – make a tube for protection
Marine worms
Oligochaeta
Polychaeta
Hirudinea
Hirudinea
• No bristles or parapodia, have suckers
• E.g. – leeches (blood suckers)
Leeches are Ectoparasites
Leach attacking a slug
Leech Removal?
• use your fingernail or something flat to
break the seal of their suckers
Irritating them can cause
them to regurgitate
their stomach contents
in the wound, risking
infection or disease
Medicinal uses
• Past – to suck out evil blood, to remove
bruises
Medicinal uses
• Present – reattachment surgery, blood
thinner
• Leech saliva contains compounds that reduce
pain, prevent clotting and dilate blood vessels.
This prevents the tissue from dying off and
allows the body to reestablish good blood flow
to the reattached part.
Summary: A 45-year-old, white male patient who suffered a complete avulsion of the
upper two-thirds of his right ear. The ear was reattached by doing a microvascular
anastomosis of a small artery anteriorly. No veins were available for anastomosis.
Soon after anastomosis, there was obvious venous congestion. Medicinal leeches
were used for treating venous congestion
48 Hours:
3 leeches have been
applied every 8
hours.
Following the initial
application, obvious
improvement was
noted
24 Hours:
Photograph shows
severe venous
congestion in the
reimplanted ear
following complete
avulsion.
6 Days:
The entire reimplanted
ear was viable and
healing well.
72 Hours:
3 leeches have been applied
every 8 hours for periods of
15 to 30 minutes. Marked
improvement in color with
decreased swelling and
congestion was noted.
Two Months:
Complete survival of reattached ear
Also testing to be able to…
• treat arthritis, blood clotting disorders, and
varicose veins.
Demi Moore Leech Therapy?
http://www.youtub
e.com/watch?v=bYe
qPvv5s_E
Giant Leeches
Earthworm
Structure
Earthworm structure
• Prostomuim – 1st segment, before mouth,
contains lots of sensory nerves
Earthworm structure
• Clitellum – thick band around the worm,
involved in reproduction
Earthworm structure
• Setae – little bristles that give the worm
traction for movement
Earthworm structure
• Mouth – entrance to the digestive system
Earthworm structure
• Pharynx – (throat) sucks in food
Earthworm structure
• Esophagus – carries food from the pharynx to
the crop
Earthworm structure
• Crop – stores food, lets worm eat a lot of food
at one time and digest it later
Earthworm structure
• Gizzard – grinds the food
Earthworm structure
• Intestines – finishes digestion, absorbs food
Earthworm structure
• Anus – exit of the digestive system
Earthworm structure
• Aortic arches – 5 pairs (hearts), pump blood
Earthworm structure
• Dorsal blood vessel – carries blood away from
the hearts
Earthworm structure
• Ventral blood vessel – carries blood back to
the hearts
Earthworm structure
• Brain – coordinates and controls the body
Earthworm structure
• Ventral nerve cord – carries messages
between the brain and the body
Earthworm structure
• Ganglia – bundles of nerves
Earthworm structure
• Seminal vesicles – store sperm
Earthworm structure
• Seminal receptacles – receive sperm from
other worm
Earthworm structure
• Muscles – both longitudinal and circular – lets
them lengthen and shorten their bodies
Earthworm structure
• Cuticle – non-cellular layer that protects the
skin from gritty soil
Earthworm structure
• Nephridia – collect, concentrate, and
eliminate wastes, don’t lose as much water
Earthworm reproduction
• hermaphrodites – exchange sperm
• Night crawlers also mate on the surface.
They are hermaphroditic but do not selffertilize. Following mating, each worm
forms a tiny, lemon-shaped cocoon out
of a liquid secreted from its clitellum.
The sperm and egg cells are deposited
inside the cocoon, and it is buried. After
a two- to four-week gestation period, the
baby worms emerge.