Nematoda (Roundworms) PDF
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This document provides information about the phylum Nematoda, commonly known as roundworms. It includes details about their characteristics, classification, general features, embryonic development, reproductive systems, life cycles of different species, and diseases caused by these organisms. The document uses diagrams and illustrations to elaborate on the topic.
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Phylum Nematoda (Roundworms) Kingdom: ANIMALIA PROTOZOA METAZOA kingdom : Prototista Eg : Ameoba PARAZOA EUMETAZO PHY : PORIFERA...
Phylum Nematoda (Roundworms) Kingdom: ANIMALIA PROTOZOA METAZOA kingdom : Prototista Eg : Ameoba PARAZOA EUMETAZO PHY : PORIFERA A Eg : Sponges DIPLOBLASTIC TRIPLOBLASTIC RADIATA BILATERIA PHY : COELENTERATA Eg : Hydra ACOELOMATA PSEUDOCOELOMATA EUCOELOMATA PHY : PLATYHELMINTHE PHY : ASCHELMINTHES(NEMATODA) Fasciola, Schistosoma Eg :) Ascaris PHY : PHY : PHY : PHY : PHY : ANNELIDA ARTHROPODA MOLLUSCA ECHINODERMATA CHORDATA 12,000 species Phylum: 500,000 possible Nematoda Only longitudinal muscles Noncellular cuticle with several layers Pseudocoelomate Found everywhere Soil Oceans Polar ice Hot springs Parasites of nearly all plant and animal species! 3 General Features of Nematodes They are triploblastic and pseudocoelomates. They may parasitic or free-living forms. Have elongated, cylindrical, smooth, unsegmented, flesh-colored bodies. Body is usually tapered to a pointed posterior end, and to a rounded anterior end. The body is covered by a noncellular, highly resistant coating “the cuticle” They have complete digestive system with mouth, oesophagus, midgut and anus. All are separate sexes; the female is usually larger than the male. There are neither respiratory nor circulatory organs. General Features of Nematodes Excretory organs are simple consisting of one or two cells or renettes. The nervous system is composed of a nerve ring around the oesophagus from which arise anterior peripheral nerves and posterior nerves cords. Embryonic Development Protostome Blastopore becomes mouth Deuterostome Blastopore becomes anus 6 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Nematode Reproductive Systems 7 Dioecious 8 Ascaris lumbricoides Roundworm of man. 1.2 billion people were infected with it. Females lay 200,000 eggs a day. Unsanitary habits contaminate ground 9 Life Cycle of Ascaris Lumbricoides Hookworms Anterior end hooks. Ancylostoma duodenale Feed on blood. Cause anemia. 13 Dracunculus medinensis (guinea worms) Guinea worm infections are now confined to sub-Saharan Africa. Adults are threadlike nematode worms that can grow to 1 meter in length. The adult lives in humans and the intermediate host is tiny crustaceans. Humans become infected when they drink water containing the crustaceans. There is no cure for Guinea worms and the only way to remove one is to slowly the worm out on a stick. If the worm breaks, a serious bacterial infection results.
