phylum: annelida
DESCRIPTION
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. - PowerPoint PPT PresentationTRANSCRIPT
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
Bristle worm
If touched, the setae will detach and lodge in the skin causing burning, itching, and numbness from the toxins they contain
Venomous Setae
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
24 Hours:Photograph shows severe venous congestion in the reimplanted ear following complete avulsion.
48 Hours:3 leeches have been applied every 8 hours. Following the initial application, obvious improvement was noted
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 re-attached ear
Also testing to be able to…
• treat arthritis, blood clotting disorders, and varicose veins.
Demi Moore Leech Therapy?
http://www.youtube.com/watch?v=bYeqPvv5s_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 self-fertilize. 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.