1. Three most common worm phyla~ 1.Platyhelminthes (flat worms) 2.Nematoda (round worms) 3.Annelida (segmented worms)

2. All worms: *Are soft-bodied *long *legless (a few have appendages) *have bilateral symmetry *Cephalization ~ an anterior, or head region where most of the sensory organs and nerve cells are concentrated. *Bodies develop from 3 cell layers a. Ectoderm - Epidermis b. Mesoderm c. Endoderm - Gastrodermis

3. Embryology

4. Germ Layers Wikipedia Triploblasty is a condition of the blastula in which there are three primary germ layers: the ectoderm, mesoderm, and endoderm. The germ layers form during gastrulation of the blastula. Additionally, the term may refer to any ovum in which the blastoderm splits into three layers. All higher and intermediate animals (from flat worms to humans), arise from a triploblastic ovum. Triploblastic organisms are organisms which develop from such an ovum. Generally speaking, triploblastic organisms belong to the Bilateria subregnum. Triploblastic organisms generally possess bilateral symmetry, which is where the clade Bilateria takes its name. Simpler animals qualified as diploblastic, such as cnidaria (which include jellyfish, corals and hydra), possess two germ layers. Even simpler animals such as sponges within the formally termed Porifera phylum contain no true tissues.

5. Germ Layers Earthlife.net Diploblastic animals have two cell layers to their bodies, an outer Ectoderm and an inner Endoderm, between these two layers may be an amount of noncellular material. Triplobastic animals have 3 cell layers in their bodies, Ectoderm (Outer layer) Mesoderm (middle layer) and Endoderm (inner layer), simpler animals have only 2 cell layers in their bodies and are called diploblastic. Body cavities of any sort only exist in triploblastic animals. These layers form in the embryo during a process called gastrulation and later give rise to different parts of the body. Thus the Ectoderm will eventually become, the epidermis of the skin, sweat and sebaceous glands, epidermal coverings (hair, feathers, scales, horns etc.) and the nervous system including those parts of the sense organs that are sensory, rather than supportive. The mesoderm gives rise to the skeleton, the muscles, the dermis of the skin, blood and blood vessels, mesenteries and the lining of the coelomic cavity. From the endoderm arise the lining of the guts, lungs and urethra as well as the urinary bladder, the thyroid, parathyroid and thymus and the secretory parts of the liver and pancreas.

6. Body Cavity Earthlife.net Acoelomate animals are called acoelomates and they have no true body cavity. The acoelomate phyla are Placozoa, Porifera, Cnidaria, Ctenophora, Platyhelminthes, Mesozoa, Nemertina, Gnathostomulida. Pseudocoelomate animals have a pseudocoelom. They have a body cavity but it is not lined with mesodermal cells. It exists between the mesoderm and the endoderm that makes up the walls of the gut. It does not have supportive mesodermal mesenteries. The pseudocoelomate phyla are Gastrotricha, Rotifera, Nematoda, Nematomorpha, Kinorhyncha, Loricifera, Acanthocephala. Coelomate animals have a coelom, this is a body cavity that has a mesodermal lining. Coeloms arise in two different ways. Through splitting of the mesoderm cell mass which arises from the walls of the archenteron in which case it is called a schizocoelom. Or from the invagination of parts of the endodermal aspect of the archenteron, when it is called an enterocoelom. The coelomate phyla are Entoprocta, Ectoprocta, Phoronida, Brachiopoda, Mollusca, Priapulida, Sipuncula, Echiura, Annelida, Tardigrada, Pentastoma, Onychophora, Arthropoda, Pogonophora, Echinodermata, Chaetognatha, Hemichordata, Chordata.

7. Body Cavity

10. Phylum Platyhelminthes Have a thin, flat body, so are commonly called flatworms 1.Class Turbellaria- Free living flatworms ~ *illustrated by planarians, basically s strip of flat tissue that ends in a triangular point. *Have eye spots that can detect the presence and direction of light. *Have an elaborate nervous system, having a mass of nerve tissue in the head, two longitudinal nerves and several transverse nerves *Has cilia on its ventral surface to propel it over the layer of slime it secretes. *Epidermis, or outermost covering, is very thin. *Also contains gastroderm and mesoderm. *Has flame cells ~ hollow bulbs containing a tuft of cilia that beat vigorously, used to aid in excretion of wastes and excess water. *Asexual regeneration and sexual reproduction. All are hermaphrodites

11. Digestion Pharynx- muscular tubelike structure that extends out of the mouth and sucks up food particles Branched intestines- enzymes partially digest food in the intestines Cells lining intestine engulf and complete digestion Indigestible food is egested back through the pharynx

12. Respiration and Circulation The thin body and extensive digestive tract of the planarian keep most of the animal’s cells near food and the environment. Diffusion on the cellular level can thus accomplish respiration and circulation efficiently. http://www.youtube.com/watch?v=Fq_aSR5FK0Y&feature=fvwrel http://www.youtube.com/watch?v=osuABmTutZM

15. 2.Parasitic flatworms ~ depends on the host for nourishment Scientists divide parasitic flatworms into two groups: flukes and tapeworms Phylum Platyhelminthes Class Trematoda: The Flukes Class Cestoda: The Tapeworms *Few sensory organs as adults *No external cilia as adults *Tegument ~ thick protective body covering * Suckers and/or hooks for attachment to hosts

16. Tapeworm Proglottids - segments of body of tapeworm for reproduction. Scolex - bulb-shaped head

17. http://www.denniskunkel.com/DK/Misc._ Invertebrates/23995C.html

18. Phylum Platyhelminthes Class Trematoda Sheep Liver Fluke – Fasciola hepatica cdc.gov Fascioliasis- People usually become infected by eating raw watercress or other water plants contaminated with immature parasite larvae. The immature larval flukes migrate through the intestinal wall, the abdominal cavity, and the liver tissue, into the bile ducts, where they develop into mature adult flukes, which produce eggs. The pathology typically is most pronounced in the bile ducts and liver. 1.Adult fluke in liver of sheep or human 2.Adult fluke releases fertilized eggs which are egested with feces 3.Eggs hatch releasing ciliated larva in a body of water 4.Ciliated larva enter a snail= intermediate host- temporarily harbors immature parasite 5.Immature fluke develops and reproduces asexually in snail 6.Young flukes leave snails and attach to vegetation as cysts 7.Sheep or human eats the plant with the cyst http://www.cdc.gov/parasites/fasciola/

20. Phylum Platyhelminthes Class Cestoda Pork Tapeworm – Taenia solium cdc.gov Taeniasis- in humans is a parasitic infection caused by the tapeworm species Taenia saginata (beef tapeworm), Taenia solium (pork tapeworm), and Taenia asiatica (Asian tapeworm). Humans can become infected with these tapeworms by eating raw or undercooked beef (T. saginata) or pork (T. solium and T. asiatica). People with taeniasis may not know they have a tapeworm infection because symptoms are usually mild or nonexistent. Cysticercosis- A parasitic tissue infection caused by larval cysts of the tapeworm Taenia solium. These larval cysts infect brain, muscle, or other tissue, and are a major cause of adult onset seizures in most low-income countries. A person gets cysticercosis by swallowing eggs found in the feces of a person who has an intestinal tapeworm. http://www.cdc.gov/parasites/taeniasis/http://www.cdc.gov/parasites/cysticercosis/

21. Life Cycle Resulting in Taeniasis 1.Each proglottid produces, fertilizes, and stores eggs as it lives inside human 2.Mature proglottid breaks off and is egested with feces 3.Pig (intermediate host) eats proglottid 4.Eggs are released and hatch in pig intestine 5.Larvae enter blood stream and are transported to muscle tissue throughout pigs body 6.Larvae form cysts or bladdar worms on muscle tissue 7.Human eats poorly cooked pork

22. Branch off The Life Cycle Resulting in Cysticercosis 1.Each proglottid produces, fertilizes, and stores eggs as it lives inside human 2.Mature proglottid breaks off and is egested with feces 3.Human (intermediate host) eats proglottid 4.Eggs are released and hatch in human intestine 5.Larvae enter blood stream and are transported to muscle tissue throughout the humans body 6.Larvae form cysts or bladdar worms on muscle tissue in human