Phylum Platyhelminthes and Nertea Acoelmate Body Plan General Zoology BIO 120 Lecture NOVA Loudoun Campus Fall 2013 BIO 120 Objectives 8 Chapter 8 Objectives Please respond to the following questions in preparation for the lecture evaluation on this material 1 To which phylum do flatworms belong What does Platyhelminthes mean How many species of flatworms are there 2 What are the four classes of Platyhelminthes and what sorts of organisms are included in each 3 What are six general characteristics of Platyhelminthes NOTE students should refer to the information box on p 164 Where do flatworms live What type of symmetry do they possess How many germ or tissue layers do they possess and what are they called What type of gut do they possess Do they possess a coelem Do they possess a nervous system respiratory system and urinary system What is the cerebral ganglion 4 Are turbellarians free living or parasitic Where do turbellarians live How do turbellarians move How are rhabdoids and cilia involved in locomotion Do turbellarians possess a mouth pharynx and intestine Do turbellarians possess a brain How do they reproduce NOTE students should be able to recreate Figure 8 7 and label the occeli auricles mouth pharynx and intestines 5 Are trematodes free living or parasitic What are two adaptations do trematodes possess for parasitism What are microtiches What are the oral sucker and acetabulum Do they have cilia or advanced sense organs What is the general digenean life cycle NOTE students should understand the life cycle of the fluke Schistosoma mansoni from Figure 8 13 and be able to recreate Figure 8 2a and label the oral sucker pharynx and intestines 6 Are monogeneans free living or parasitic What are the prohaptor buccal sucker and opishthaptor Where are monogenetic flukes found How is their life cycle different than those of many trematodes NOTE students should be able to recreate Figure 8 2c and label the prohaptor mouth intestines and opisthaptor 7 Are cestodes free living or parasitic What are the scolex strobili proglottids and genital pores Do cestodes possess a digestive system or advanced sense organs What are microthriches NOTE students should understand the life cycle of the beef tapeworm Taenia saginata from Figure 8 15 8 To which phylum do nemerteans or ribbon worms belong What are three important differences between nemerteans and turbellarians Phylum Platyhelminthes and Nertea Acoelmate Body Plan BIO 120 Objectives 8 1 Platyhelminthes a Phylum Platyhelminthes b Platyhelminthes flat worm c 25 000 species of flatworms 2 Classes of Platyhelminthes a Turbellaria b Trematoda c Monogenea d Cestoda 3 Characteristics of Platyhelminthes a Unsegmented b Are either free living or parasitic c Triploblastic i Ectoderm ii Mesoderm iii Endoderm d Acoelomate e Bilaterally symmetrical f Flattened dorsoventrally g Cephalized h Have excretory system i One way digestive system j Most are monoecious k l Cerebral ganglion turbellarian head brain like feature Inhabit marine freshwater land and hosts 4 Turbellaria a Almost completely free living b c Movement Inhabit freshwater marine and terrestrial habitats i Ciliary action ii Rhabdoids secrete mucous d Posses mouth pharynx and intestine e Posses brain or ganglia of nerves f Almost all are monoecious Phylum Platyhelminthes and Nertea Acoelmate Body Plan 5 Trematodes BIO 120 Objectives 8 a Parasitic endoparasites i Suckers and hooks for attachment ii Increased reproduction capability iii Lack mouth or digestive tract absorb nutrients across tegument b Digenetic flukes almost always have 2 hosts c Microtiches folds of tegument to increase surface area for absorption of nutrients d Oral sucker hookless sucker surrounding mouth for attachment to host e Acetabulum hookless sucker on ventral surface for attachment to host f Lack cilia and advanced sense organs Phylum Platyhelminthes and Nertea Acoelmate Body Plan 6 Monogeneans BIO 120 Objectives 8 a Parasitic mainly of fish ectoparasites and endoparasites b Prohaptor anterior and opishaptor posterior for host attachment c Habitat in or on gills of fish d One host Phylum Platyhelminthes and Nertea Acoelmate Body Plan 7 Cestodes BIO 120 Objectives 8 a Parasitic b Scolex head with hooks and suckers c Strobili whole body region d Proglottid repeated individual sections e Genital pores release fertilized eggs in females f Lack digestive system and advanced sense organs g Microthriches 8 Nemerteans ribbon worms a Phylum nemertea b Nemerteans vs turbellarians i Have proboscis to capture food and bring to mouth ii Have true anus iii Have complete digestive system iv Closed circulatory system v Body filled with partially gelatinous parenchyma vi Rhyncocoel vii Have four lobed brain