Lecture 4: Animal Kingdom (lec 4 animal.pdf)

http://www.ucmp.berkeley.edu/porifera/images/GM10sm.jpg Kingdom Animalia Subkingdom Metazoa Br...

http://www.ucmp.berkeley.edu/porifera/images/GM10sm.jpg Kingdom Animalia Subkingdom Metazoa Branch Parazoa Phylum Porifera (Sponges) (Pore bearers) They are stationary and rooted in their places, and so they were considered as plants for centuries, but eventually their animal nature was discovered. The Porifera (15,000 species) represent Metazoa at the cellular level of organization. Sponges are usually found in relatively shallow water, but some groups live at great depths. Few species live in freshwater. General characters of Sponges 1. They are radially symmetrical. 2. Body with many pores or ostia through which water flows. 3. The internal cavity is known as spongocoel lined with choanocytes (flagellated cells). 4. They are holozoic with no mouth, no digestive system and digestion is intracellular. 5. They respire and excrete by simple diffusion. Vedio  Kingdom Animalia Subkingdom Metazoa Branch Eumetazoa (Enterozoa) Division Radiata (Diploblastica) Phylum Cnidaria (Coelenterata) Classification of Phylum Cnidaria: - Phylum Cnidaria is classified into 4 classes which are: 1- Class Hydrozoa (Gr., hydro, water + zoon, animal) = Water animals, Examples: Hydra, Obelia. 2- Class Scyphozoa (True jelly-fish), Example: Aurelia. 3- Class Cubozoa (Cube jelly-fish), Examples: Box jellies (Sea wasps). 4- Class Anthozoa (Actinozoa) (Gr., anthos, flower + zoon, animal) = Flower animals - Class Anthozoa is subdivided into two subclasses: a- Subclass: Alcyonaria (Soft corals), Examples: Alcyonium, Xenia. b- Subclass: Zoantharia (hard corals), Examples: Sea anemones & stony corals. Alcyonium Xenia Sea anemone stony coral  General characters of Cnidarians 1) They are solitary or colonial, sedentary or free swimming. 2) They are aquatic, mostly marine, some are fresh water. 3) The body is radially symmetrical. 4) Most cnidarians are carnivorous. 5) There is a central gastro-vascular cavity (coelenteron or enteron) which is communicated with the exterior by a single opening, the mouth. 6) The mouth is surrounded by tentacles arranged in one or more whorls. The tentacles help in food capture, ingestion and for defense. 7) Body wall has peculiar stinging cells called cnidocytes which are more abundant on the tentacles than elsewhere.  Some Jellyfishes Show Luminescence Bioluminescence is the emission of visible light by biological systems, which arises from enzyme-catalyzed chemical reactions. ‫جائزة الفضل فكرة‬  Helminthology (Science of studying worms) These are triploblastic, dividing according to the presence or absence of coelom (body cavity) into: 2- Pseudocoelomate 1- Acoelomate e.g. e.g. Platyhelminthes Nematoda 3- Coelomate e.g. (Flatworms) ( round worms) Annelida & higher taxa * Has no body cavity; spaces between organs * Has a body cavity ( ring worms) are filled by (pseudocoelom) lined * Has a body cavity parenchyma externally by mesoderm (coelom) lined externally and internally by and internally by 7 endoderm. mesoderm  Kingdom Animalia Subkingdom Metazoa Branch Eumetazoa (Enterozoa) Division Bilateria (Triploblastica) Section Acoelomata Phylum Platyhelminthes (Flatworms) General characters 1- Body dorso-ventrally compressed with bilateral symmetry. 2- Triploblastic animals. 3- Epidermis is soft and ciliated as in Turbellaria or covered by tegument and with external suckers or hooks or both for attachment to host as in Monogenea, Digenea and Cestoda. 4- There is no secondary body cavity (acoelomate). 5- The muscular system is well developed. 6- Incomplete digestive system (with mouth, no anus). 7- Excretory system represented by flame cells or solenocytes. 8- It is the first phylum possesses some sense organs and central nervous system. 9- Sexes usually monoecious or hermaphrodite (except Schistosoma) with a complicated reproductive system. 10- No skeletal, circulatory or respiratory systems.  Classification of Phylum Platyhelminthes: - Five classes of Phylum Platyhelminthes are recently recognized: 1- Class: Turbellaria, mostly free living. 2- Class: Monogenea, typically ectoparasitic. 3- Class: Aspidogastrea (Aspidobothrea) 4- Class: Digenea, endoparasitic. E.g. Fasciola, Schistosoma 5- Class: Cestoda (Tape worms), endoparasitic & segmented. E.g. Taenia Class Digenea General characters 1- All endoparasitic 2- Body is flattened and unsegmented 3- Attach to their hosts by suckers 4- Alimentary canal with mouth and no anus 5- Complex muscle layers 6- Excretory organs and nervous system are present The adult worms are found in different tissues of the primary host (vertebrate). According to their location in the body of the host, digenetic trematodes are grouped as follows: 1- Hepatic or liver flukes, e.g. Fasciola 2- Blood flukes, e.g. Schistosoma 3- Intestinal flukes, e.g. Heterophyes  Liver Flukes (Fasciola spp.) - The adult worms live in the bile ducts of the liver of cattle, sheep and pigs. - It produces the disease known as Fascioliasis (liver rot). - Fasciola gigantica is the common liver fluke in Egypt, while Fasciola hepatica (human liver fluke) is more common in Europe and Australia. - Mode of infection: When man eats vegetables or animals ingest the aquatic plants which contain the encysted metacercariae (infective stage). Life cycle of Fasciola Infective stage Mode of transmission Final host Intermediate host operculum eg g  Blood Flukes (Schistosoma spp. or Bilharzia) - Schistosomes cause serious disease called Schistosomiasis or Bilharziasis. - Mode of infection: Cercariae (infective stage) penetrate the skin of man when washing, walking or bathing in infected water. Infective stage Oncomelania Biomphalaria Bulinus Final host Intermediate host Venous plexus of Mesenteric bladder vein  Class Cestoda (Tape worms or Gutless flatworms) General characters 1- Elongated ribbon like 2- Composed of head/scolex carries sucker, hooks, bothria, a rostellum for attachment 3- Neck having activity dividing cells from which proglottid are formed 4- Three types of proglottid are found which are: b [a] Immature (immature sexual organs) [b] Mature (mature sexual organs) c [c] Gravid (uterus filled with eggs) 5- Digestive system absent and they absorb their food by tegument 6- Nervous system composed of nerve bundles and nerve cords 7- Excretory system composed of flame cells. They have specials ducts, collecting tubules unite to form main longitudinal excretory canals on each side of proglottid and connected by transverse excretory canal. They open to exterior by single excretory pore. 8- Hermaphrodite 9- Reproduction takes place by cross fertilization and self fertilization  EX. Taeniarhynchus saginatus (Taenia saginata) & T. solium Taenia saginata (beef tapeworm) Taenia solium (pork tapeworm) Measures 10-12 meters and composed of Measures 3-5 meters and composed of 1000-2000 proglottid 800-1000 proglottid Intermediate host is Sheep Intermediate host is Pig Final host is Man, they are intestinal parasites Mode of infection: When man eats raw or insufficiently cooked meat of cows or camel in case of Taenia saginata or meat of pig in case of T. solium which contain the bladder worms (infective stage) in their muscles. Disease it may cause: this is a human intestinal parasite causing Taeniasis which may result in mild anaemia, digestive & nervous disorders, and loss of weight.  Life cycle of Taenia Reproductive system of Taenia Life cycle of Taenia The bladder worm (cysticercus worm) Oncosphere With 6 hooklets  Kingdom Animalia Subkingdom Metazoa Branch Eumetazoa (Enterozoa) Division Bilateria (Triploblastica) Section Acoelomata Phylum Nematoda (Thread worms) General characters 1- They are bilaterally symmetrical, unsegmented triploblastic worms. 2- Pseudocoelomate animals with slender cylindrical bodies. 3- Alimentary canal is straight and complete with mouth and anus (or cloacal opening). 4- Respiratory and circulatory systems are absent. 5- Cuticle usually present and cilia are absent. 6- Body wall with longitudinal muscles only. 7- Excretory system of glandular organs or a system of canals or both. 8- Dioecious; male is smaller than female. 9- Fertilization is internal. 10-The nervous system is composed of a nerve ring around the oesophagus from which arise 6 short anterior and 6 long posterior nerve cords. 11- Eggs are shelled covering with a chitinous shell. 12- Development is usually direct and no asexual reproduction or regeneration occurs. Classification of Phylum Nematoda Phylum Nematoda is classified into 2 main classes: 1. Class: Secernentea (Phasmidea), It includes: a. Order: Ascaridida e.g. Ascaris lumbricoides (Eel worm) b. Order: Strongylida e.g. Ancylostoma duodenale (Hook worm) Ascaris lumbricoides (Eel worm) - This is a common intestinal parasite of man (children in particular) & other animals. - It causes to the human a disease known as Ascariasis: [a] In mild infections, it causes abdominal disorders [b] In severe cases, it causes general weakness, intestinal obstruction, hepatitis obstruction of biliary passages & further of the trachea, lead to suffocation‫االختناق‬ - Mode of infection: When man eats vegetables & food or drinks water contaminated with the second rhabditiform larvae (infective stage). Morphology of Ascaris [A] Anterior end 1- Head has a terminal mouth, surrounded by three lips 2- Dorsal lip bear two double sensory papillae, and each latero-ventral lip has one double sensory papillae 3- Each latero-ventral lip has amphid which are olfactory chemoreceptors 4- Lips have fine teeth 5- Excretory pore behind lips [B] Cuticle of the body Smooth with Four longitudinal epidermal lines (one dorsal, one ventral, two lateral) [C] Posterior end 1- Male has cloacal aperture provided with number of anal papillae with two equal spicules project 2- Female has vulva on the anterior part Life cycle of Ascaris  Ancylostoma duodenale (Human hook-worm) - This is a common intestinal parasite of man (children in particular) & other animals. - It causes to severe anemia to man. - It known as hook-worms as the anterior end of both sexes is bent dorsally as hool- shape but rhe worms have no hooks. - Mode of infection: When man eats vegetables & food or drinks water contaminated with the filariform larvae (infective stage). Life cycle