WFSC 335 Exam # 2 Study Guide Phylum Platyhelminthes Flatworm Acoelomate Bilaterally symmetrical and sometimes display cephalizationwhere sensory organs tend to be towards the anterior end of the organism Triploblastic Dorso-ventrally flattened 3 well developed muscle layers o Circular o Longitudinal o Oblique (transverse) Digestive System: Mouth, pharynx, gastrovasuclar cavity o No anus b/c mouth is used for ingestion and egestion Nervous System: Ganglia (basic brain), transverse nerves, nerve cord, eyespot Excretory system: Protonephiridia flame cells, ducts, and pores Excretory pore Excretory canals Reproduction: Hermaphrodites but do NOT self fertilize, reproduce sexually Testissperm duct Ovariesoviduct Yolk gland 4 classes: 3 parasitic and 1 free living Turbellia (free living) o Mostly aquatic o Body covered with cilia o Rhabdites – secretions released by glands to form mucus; aid in movement o Most have eye spots except those species that live in caves o Auricle – ear like projections o Hermaphroditic but also reproduce asexually by fission or budding o Vitellaria – female reproductive system o Planaria: . Dugesia species . Largest of freshwater triclads (4-30 mm in length) Triclad – intestine has 3 branches, which is where the name triclad comes from . Freshwater carnivores . Move by using cilia Monogenea o Have Syncytial epidermis – multinucleated cell mass from fusion of cells (one huge skin cell) o Marine and freshwater o Mostly ectoparasites of aquatic animals . 1 host during lifecycle, no intermediate host o Has suckers and clamps o Opisthaptor – posterior hook attachment o Hermaphroditic (monoecious) . Reproduce sexually inside host o Direct development . Free swimming larvae (gyrodactyloid) Trematoda (“Flukes”) o Have Syncytial epidermis – multinucleated cell mass from fusion of cells (one huge skin cell) o Parasitic most have intermediate host (usually invertebrates) . Endo and ectoparasites . Reproduce asexually and sexually Only reproduce sexually once in adult stage Reproduce asexually in intermediate host o 2 subclasses . Aspidogastrea Large ventral sucker divided by septa, forming row or suckers Alveoli – suckerlets Simple life cycle . Digeneans (2 generations) endoparasites (intestines) life cycle: alternation of generation-like system composed of an asexual aspect (Polyembryony) invertebrate intermediate host and sexual phase (Anisogamy) vertebrate definitive host incomplete digestive tract with no anus Cestoda (Tapeworms): o Have Syncytial epidermis – multinucleated cell mass from fusion of cells (one huge skin cell) o Primarily found in intestines of vertebrates as adults and in the coelom of the definitive host o Adults usually have 2 or more suckers or sucking surfaces on specialized attachment called scolex (anchor) o No digestive organs o Monoecious o Indirect development with 2 hosts o Body is made up of 4 segments . Scolex (head) . Immature proglottid . Mature proglottid . Gravid proglottid o 1 set of male and female reproductive organs in each proglottid o Subclass Cestodaria . Primitive tapeworms . Mostly body cavity parasites (not intestinal tract) . Neotenic – larva may be able to reproduce without adult stages . Unsegmented body, no scolex . Hermaphroditic no need for sexual reproduction and only 1 set of male and female organs per individual unlike “true” tapeworms o Subclass Eucestoda (True Tapeworms) . Order Pseudophyllidea Bothraited scolex – shallow sucking grooves Vitellaria and testes scattered laterally Genital pore located medially Eggs operculated and protein tanned Life cycles generally use 3 hosts2 intermediate hosts and the definitive host . Order Proteocephalata Parasites as adults in freshwater fish, amphibians, and reptiles Have acetabulate scolex – cup like with a muscular wall Testes and vitellaria scattered laterally in proglottids Genital pore is laterally situated Uterus is saccate . Order Cyclophyllidea Parasites as adults in birds and mammals Life cycles are terrestrial NOT aquatic o Generally involve intermediate host o Larvae are some form of a bladder worm Acetabulated scolex/rostellum present Genital pores are laterally situated Vitellaria compact in posterior region of proglottid.