Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Representative Pseudocoelmate Phyla Nematomorpha Rotifera Acanthocephala Jenna Hellack F 2000 Nematoda Pseudocoelomates • The phyla are eumetatzoans, have bilateral symmetry (grade Bilateria) and are in division Protostomia. • The blastocoel of the embryo is the body cavity. The body cavity is not lined with a mesoderm. Jenna Hellack F 2000 Taxonomy • Phylum Nematomorpha • Phylum Acanthocephala • Phylum Rotifera – Philodina • Phylum Nematoda – Ascaris, Enterobius, Necator, Ancylostoma, Wuchereria, Dracunculus, Turbatrix, Dirofilaria, Trichinella Jenna Hellack F 2000 Taxonomy Phylum Nematomorpha • Larva parasites arthropods • Adults free-living in freshwater (do not feed) • Works are striking because of the extremely long and threadlike body. Jenna Hellack F 2000 Taxonomy Phylum Acanthocephala • Have a short anterior proboscis covered with recurved spines • Has ability to secrete chemicals that modify the behavior of host species. Jenna Hellack F 2000 Taxonomy Phylum Rotifera • Genus - Philodina • Some unique characteristics – – – – Jenna Hellack F 2000 Mastax Ciliated corona Toes Parthenogenesis Systems Taxonomy Phylum Nematoda • Some characteristics – – – – Amoeboid sperm Longitudinal muscle only Muscle attach to nerves 6-layered cuticle Carrot root nematodes Heart worms (Dirofilaria) Jenna Hellack F 2000 Pepper nematodes Systems of Nematoda • System I – Integumentary, skeletal, muscle and digestive • System II – Excretory, respiratory, circulatory and nervous • System III – Endocrine and reproductive Jenna Hellack F 2000 Taxonomy Systems I • Integumentary - syncytial, one cell layer; secretes 6-layered cuticle. • Skeletal - hydrostatic • Muscle - longitudinal muscle only, muscles send fibers to nerves • Digestive - complete but not complex; mouth pharynx, intestine, anus; no digestive glands System II Jenna Hellack F 2000 System III Taxonomy Systems II • Excretory - excretory tubes and renette glands probably remnants of flame cells like system. • Respiratory - none; many are anaerobic • Circulatory - none; use pseudocoelom • Nervous - nerve ring around pharynx; dorsal and ventral cords with lateral lines System III Jenna Hellack F 2000 Taxonomy Systems III • Endocrine - chemicals secreted by nervous system • Reproductive - Mostly dioecious – Sexual dimorphism - male usually smaller and has copulatory structure – Amoeboid sperm – Many with complex life cycles - particularly the parasites Jenna Hellack F 2000 Representative Genera of Nematoda • • • • • Ascaris Enterobius Necator Ancylostoma Wuchereria Jenna Hellack F 2000 • • • • Taxonomy Dracunculus Turbatrix Dirofilaria Trichinella Taxonomy Genus Ascaris Dissection Male • Intestinal roundworm – Ingested as eggs in contaminated food or dirt Jenna Hellack F 2000 Dissection Ascaris female Jenna Hellack F 2000 Taxonomy Taxonomy Ascaris male copulatory spicule Jenna Hellack F 2000 Taxonomy Genus Ancylostoma Hookworm infected by juveniles in soil burrowing into skin. Dog Hookworms Mouth Jenna Hellack F 2000 Copulatory structure of male Taxonomy Genus Dirofilaria (dog heart worms) Adult worms live in heart while the juveniles circulate in blood. They are transmitted by mosquitoes. Jenna Hellack F 2000 Taxonomy Trichinella Encysted stage In pork Jenna Hellack F 2000