Lecture Notes: Animal Classification (Protozoa-Annelida) PDF

9/17/2024 LISC101: Introduction to living systems for your reference Unit I- 1. Concept of Animal Kingdom and...

9/17/2024 LISC101: Introduction to living systems for your reference Unit I- 1. Concept of Animal Kingdom and Protista 2. Classification of Animal Phyla (B.Sc. Ist Semester) 1 References: ♠ Kotpal R.L. Modern Text Book of Zoology: Invertebrates. Rastogi Publications. ♠ Ganguli B.B., Sinha A.K. and Adhikari S. Biology of Animals (Vol 1). ♠ Parker T. Jeffery and Haswell. William A. Parker and Haswell's Zoology. A Text-book Of Zoology. Sixth edition. Vol. 1 (Protozoa to Chordata), revised by Otto Lowenstein. ♠ Ruppert E.E. and Barnes R.D. 1994. Invertebrate Zoology, 6th edition. Saunders College Publ., Philadelphia, PA. 1056 pp. 2 Dr Puja Ray 1  9/17/2024 Unit 1. Animal Classification Classification of Protozoa up to Phylum; Classification of non-chordates up to subclass; Classification of chordates up to order. 3 What is classification? There is a lot of variation between organisms, but many organisms also share common features. Scientists use common features to put organisms into groups. Grouping organisms based on their common features is called classification. Classification is sorting out all organisms into groups according to the similarities between them. 4 Dr Puja Ray 2  9/17/2024 Importance of classification? makes the study of such a wide variety of organisms easy. It projects before us a good picture of all life forms at a glance. helps us understand the interrelationship among different groups of organisms. It serves as a base for the development of other biological sciences such as biogeography etc. Various fields of applied biology such as agriculture, public health and environmental biology depends on classification of pests, disease vectors, pathogens and components of an ecosystem. 5 History of Classification Early classification systems probably grouped organisms as to whether they were beneficial or harmful. Another ancient classification system recognized 5 animal groups - domestic animals, wild animals, creeping animals, flying animals, and sea animals. 6 Dr Puja Ray 3  9/17/2024 History of Classification ARISTOTLE - *4th century BC (384 to322 BC) *Greek philosopher *divided organisms into 2 groups - plants and animals *divided animals into blood (Enaima) and bloodless (Anaima). *also divided animals into 3 groups according to how they moved - walking, flying, or swimming (land, air, or water) *his system was used into the 1600's 7 CAROLUS LINNAEUS (1707-1778)  18th century, Swedish scientist  classified plants & animals according to similarities  wrote 180 books mainly describing plant species in extreme detail.  divided living things into one of two "kingdoms" - o plant and animal kingdoms o divided each of the kingdoms into smaller groups called "genera" (singular- genus) o divided each genera into smaller groups called "species"  In his book the Systema Naturae (1735) he designed a system of naming organisms called binomial ("two names") nomenclature ("system of naming") which gave each organism 2 names - genus (plural = genera) and species (plural = species) names. Genus is always capitalized while species is never capitalized. To be written correctly, the scientific name must be either underlined or written in italics. 8 Dr Puja Ray 4  9/17/2024 CAROLUS LINNAEUS  Father of modern taxonomy Based on Carolus Linnaeus binomial nomenclature system, each organism is given a 2-part scientific name. An organism may have more than one common name, but will only have one scientific name. For ex. - mountain lion, cougar and puma are all common names for the same animal. However, its scientific name is Felis concolor. Homo sapiens: man who is wise 9 Robert Harding Whittaker American plant ecologist In 1969: proposed 5 kingdom classification based on true nucleus (eukaryotic) / absence of true nucleus (prokaryotic) based on ecology, evolution and structure The classification system The classification system begins with very big groups that include a lot of organisms and then moves down to smaller groups made up of fewer organisms. The biggest groups are called the kingdoms. 10 Dr Puja Ray 5  9/17/2024 WOESE’S THREE-DOMAIN SYSTEM: In Woese’s three-domain system, the three branches of the phylogenetic tree includes The former archaebacteria and is called the domain Archaea. The second encompasses all the remaining true bacteria and is called the domain Bacteria. The third domain, the Eukarya, includes the four remaining kingdoms (Protista, Plantae, Fungi, and Animalia). 11 WOESE’S THREE-DOMAIN SYSTEM: This classification system divides the life based on the differences in the 16S ribosomal RNA (rRNA) structure and as well as the cell’s membrane lipid structure and its sensitivity to antibiotics. 12 Dr Puja Ray 6  9/17/2024 3 Domains Archaea – odd bacteria that live in extreme environments, high salt, heat, etc. (usually called extremophiles) Bacteria – true bacteria Eukarya – have a nucleus & organelles (humans, animals, plants) 13 Taxonomy Domain Kingdom Phylum Class Order Family Genus Species 14 Dr Puja Ray 7  9/17/2024 Domain- Eukarya plants, animals 15 Leopard Local Names : Cheeta (Bengali), Tendwa & Cheeta (Hindi), Karda & Bibalya wagh (Marati), Chirate & Siwamgi (Kannada), Chirutai (Tamil), Puli Poolee (Malayalam) 16 Dr Puja Ray 8  9/17/2024 All living things are classified into five different kingdoms. Monera Bacteria and primitive algae Prokaryotic Single celled or multicellular without Protista tissue specialization. Eukaryotic Amoeba, Plasmodium, Trypanosoma, Organisms Fungi Moulds, mushrooms and toadstools Eukaryotic Seed bearing plants and non-seed Note: eukaryotes Plants bearing plants do have "true" Eukaryotic nuclei containing their DNA, whereas the Jellyfish, worms, arthropods, molluscs, genetic material in Animals echinoderms, amphibians, fish, reptiles, prokaryotes is birds and mammals. Eukaryotic not membrane- 17 bound. 18 Dr Puja Ray 9  9/17/2024 How many species are there? This is not an easy question to answer. About 1.8 million have been given scientific names. Thousands more are added to the list every year. The Kingdom Animalia has by far, the greatest diversity of named organisms (approximately 1,000,000 kinds or species) Compared to… – The Plantae (300,000 species), – The Fungi (70,000 species), – The Protista (31,000 species) – The Monera (10,000 species). 19 Intro to Animals (EUMETAZOA) 20 Dr Puja Ray 10  9/17/2024 Body Plans- Kinds of symmetry An animal that is irregular in shape are asymmetrical. An animal has radial symmetry if it can be divided along any plane, through a central axis, into equal halves. An animal has bilateral symmetry if it can be divided down its length into similar right and left halves forming mirror images of each other. 21 Body Plans: Kinds of Coeloms Acoelomates – animals have three cell layers with a digestive tract but no body cavities. No cavity (space) around organs Include: Porifera to flat worms Pseudocoelomates – animals with a fluid-filled body cavity partly lined with mesoderm. Space around organs but only lined with mesoderm on one side (lines body wall BUT NOT around gut) Include: round worms (nemathelminthes), rotifera Coelomates – animals with a body cavity completely surrounded by mesoderm. Body cavity (space) lined on BOTH sides by mesoderm  ex. Annelids, arthropods, molluscs, echinoderms, chordates 22 Dr Puja Ray 11  9/17/2024 Body Plans- Types of Coeloms 23 Body Plans: Kinds of Coeloms 24 Dr Puja Ray 12  9/17/2024 Protection and Support Though not all animals have a skeleton, those that can be divided into two groups: – Those with an exoskeleton – a hard, waxy coating on the outside of the body that protects internal organs, provides a framework for support, and a place for muscle attachment. – Those with an endoskeleton – support framework within the body that protects some organs and a brace for muscles to pull against. 25 Broad classification of animal kingdom based on common fundamental features 26 Dr Puja Ray 13  9/17/2024 Animal Kingdom- Classification Kingdom Animalia Sub-kingdom Protozoa Metazoa Phylum Infra-kingdom Protozoa Mesozoa Parazoa Enterozoa Phylum Phylum Mesozoa Porifera Radiata Bilateria Phylum Conti….. Cnidaria Ctenophora 27 Conti….. Bilateria Acoelomata Pseudocoelomata Eucoelomata Phylum Platyhelminthes Aschelminthes Entoprocta Nemertinea Acanthocephala Ectoprocta Annelida Chaetognatha Chordata Brachiopoda Sipunculida Echinodermata Phoronida Echiuroidea Pogonophora Mollusca Arthropoda Hemichordata 28 Dr Puja Ray 14  9/17/2024 Eukaryota 29 Animal Kingdom Major Phyla of the Animal Kingdom 30 Dr Puja Ray 15  9/17/2024 Animal classification The animal kingdom is divided into two groups: animals invertebrates vertebrates Invertebrates are animals Vertebrates are animals that do not have a backbone. They have that have a backbone / internal skeleton soft inner bodies which are held in shape by made of bones. a flexible covering of outer cells or by a They have a firm body because of the hard covering called an exoskeleton. muscles that connect to their skeleton. 31 98% of animal species are invertebrates, meaning that 2% of animal species are vertebrates. Animals Invertebrates Protozoa Porifera Cnidarians Vertebrates Ctenophora Platyhelminthes Fish Nemathelminthes Amphibians Annelids Reptiles Molluscs Birds Arthropods Mammals Echinoderms 32 Dr Puja Ray 16  9/17/2024 LIFE ON EARTH Image from: http://ology.amnh.org/biodiversity/treeoflife/pages/graph.html 33 Major Phyla of the Animal Kingdom The most important features of these major animal phyla, their classification and examples are as follows: There are 10 major phyla in the animal kingdom from Protozoa to Chordata. Of these, phylum Protozoa is now placed in the Kingdom Protista. 34 Dr Puja Ray 17  9/17/2024 35 Characteristics of ALL Animals: 1. Eukaryotic 2. Heterotrophic 3. Multicellular/differentiated cells 4. Cells have NO cell walls 5. Movement 6. Reproduction (Mostly sexual) 36 Dr Puja Ray 18  9/17/2024 Phylum – Protozoa (protos= first, zoon= animal) First studied by Leeuwenhoek. Term Protozoa coined by Goldfuss Protozoology Defined as microscopic and acellular animalcules, without tissues and organs having one or more nuclei. They exist either single or in colonies which differ from a metazoan in having all the individuals alike except when engaged in reproductive activities. 37 Phylum Protozoa- General characteristics ♠ Aquatic, primitive microorganisms. ♠ Single-celled, acellular organisms – eukaryotic. ♠ Free living or parasitic; some live in colonies, others solitary. Some commensal or mutualistic ♠ Size - varies greatly = microscopic (3 to 1,000 microns). ♠ No common basic structure, size or shape. ♠ Symmetry = all types (bilateral, radial, spherical, or asymmetrical) ♠ Locomotion by pseudopodia, flagella, or cilia or none. 38 Dr Puja Ray 19  9/17/2024 Phylum Protozoa- General characteristics ♠ Body may be bound by delicate membrane/ firm pellicle (proteinaceous) (absent in amoeba) / test ♠ Mostly naked, but few have simple protective exoskeletons (CaCo3/ silica). Ex. = Arcella Radiolaria, Foraminifera- when these protozoans die they will form deposition in the seabed (foraminiferal ooze, radiolarian ooze). 39 Phylum Protozoa- General characteristics ♠ Number of nuclei varies from one to several ♠ No germ layers, tissues, or organs; However, specialized intracellular "organelles" are present. ♠ Nutrition = autotrophic (holophytic), saprozoic, saprophytic, or holozoic, some myxotropic; digestion intracellular ♠ Respiration and excretion through body surface ♠ Reproduction: asexual = longitudinal and transverse binary fission, budding, sexual = fusion of gametes or conjugation 40 Dr Puja Ray 20  9/17/2024 41 42 Dr Puja Ray 21  9/17/2024 Proterospongia: connecting link between protozoa and sponges (Porifera) rare freshwater, single celled protist, a colonial member of the Choanoflagellata. It consists of a number of cells embedded in a jelly-like matrix. Have choanocytes and amoeboid cells Interestingly, it shows a very primitive level of cell differentiation, or specialization for different roles. Question in BHU Zoology PG entrance- Proteospongia has- 1. Choanocytes 2. Amoeboid cells 3. Both A and B 4. Mastigoamoeba like cells 43 Phylum Protozoa- Classification Phylum Protozoa Sub-phylum Sarcomastigophora Sporozoa Cnidosposa Ciliophora 44 Dr Puja Ray 22  9/17/2024 Phylum Protozoa- Classification Phylum Protozoa Sub-phylum Sarcomastigophora Sporozoa Cnidosposa Ciliophora Super-class Mastigophora Sarcodina Opalinata 45 Phylum Protozoa- Classification Phylum Protozoa Sub-phylum Sarcomastigophora Sporozoa Cnidosposa Ciliophora Super-class Mastigophora Sarcodina Opalinata class Phytomastigophorea Eg. Euglena Noctiluca Zoomastigophorea Eg. Trypanosoma Leishmania 46 Dr Puja Ray 23  9/17/2024 Phylum Protozoa- Classification Phylum Protozoa Sub-phylum Sarcomastigophora Sporozoa Cnidosposa Ciliophora Super-class Mastigophora Sarcodina Opalinata class Actinopodia Rhizopodia Piroplasmea Eg. Lithocircus Eg. Amoeba Eg. Babesia Actinophrys Entamoeba 47 Phylum Protozoa- Classification Phylum Protozoa Sub-phylum Sarcomastigophora Sporozoa Cnidosposa Ciliophora Super-class Mastigophora Sarcodina Opalinata Eg. Opalina 48 Dr Puja Ray 24  9/17/2024 Phylum Protozoa- Classification Phylum Protozoa Sub-phylum Sarcomastigophora Sporozoa Cnidosposa Ciliophora class Telosporea Toxoplasmia Haplosporia Eg. Plasmodium Eg. Haplosporidium Eg. Sarcocystis Monocystis Icthyosporidium Toxoplamsa Plasmodium Sarcocystis Haplosporidium 49 Phylum Protozoa- Classification Phylum Protozoa Sub-phylum Sarcomastigophora Sporozoa Cnidosposa Ciliophora class class Ciliata Myxosporidia Microsporidea Eg. Paramecium Balantidium Eg. Myxidium Eg. Nosema Myxobolus Nosema Paramecium Myxidium 50 Dr Puja Ray 25  9/17/2024 Phylum Protozoa- Classification Sub-phylum Sarcomastigophora ♠It gets its name from the combination of "Sarcodina" (an older term used for amoeboids) and "Mastigophora" (which is an older term for flagellates). ♠ Locomotory organs- pseudopodia or flagella or both. ♠ Nucleus one or more. ♠Nutrition – autotropic or heterotropic. ♠ Asexual reproduction by multiple or binary fission. ♠ Sexual reproduction by complete fusion or gametes – syngamy. ♠ Complicated life cycle exhibits an alternation of generations. Super-class Mastigophora Sarcodina Opalinata 51 Phylum Protozoa- Classification Super-class Mastigophora ♠ Shape: oval, circle or long ♠Body with firm pellicle ♠Locomotion by flagella ♠Asexual reproduction- longitudinal binary fission class Phytomastigophorea Zoomastigophorea Eg. Euglena Eg. Trypanosoma Noctiluca Leishmania 1. Chlorophyll bearing chromatophores 1. Chlorophyll bearing chromatophores present absent 2. Nutrition- holophytic 2. Nutrition- saprozoic or holozoic 3. Free living, fresh water or marine 3. Flagella one or many 4. Reserve food paramylon or starch 4. Reserve food glycogen 5. Sexual phase present in life cycle 5. Sexual phase absent in life cycle 52 Dr Puja Ray 26  9/17/2024 Phylum Protozoa- Classification Super-class Rhizopoda or Sarcodina ♠Body without pellicle ♠ Shape: Pleomorphic ♠Exoskeleton or endoskeleton present ♠ Locomotion by pseudopodia ♠Nutrition holozoic or saprozoic ♠Asexual reproduction- binary fission class Actinopodia Rhizopodia Piroplasmea Eg. Lithocircus Eg. Amoeba Eg. Babesia Actinophrys Entamoeba 1. Body naked or covered 1. Pseudopodia present 1. Small parasites in by membrane like test 2. Axial filaments absent RBCs 2. Axopodia with axial 2. Do not produce spores filaments Actinophrys 53 Phylum Protozoa- Classification Super-class Opalinata ♠Parasitic in toads and frogs ♠Rows of cilia all over the body ♠Nucleus many and alike Eg. Opalina, Zelleriella, Cepedia Opalina 54 Dr Puja Ray 27  9/17/2024 Phylum Protozoa- Classification Sub-phylum Sporozoa ♠Exclusively endoparasitic ♠ Locomotory organs- absent ♠Pellicle present around the body ♠ Nutrition – saprozoic ♠ Asexual reproduction by multiple fission. ♠ Sexual reproduction – syngamy. class Telosporea Toxoplasmia Haplosporia 1. Body naked or 1. Spores not formed 1. Spores case present encysted 2. Only asexual reproduction but few in cyst wall 2. Sporozoites elongated 3. Nutrition saprozoic 2. Only asexual Eg. Sarcocystis reproduction Eg. Plasmodium Toxoplamsa Eg. Haplosporidium Monocystis Icthyosporidium 55 Phylum Protozoa- Classification Sub-phylum Cnidosposa ♠ Spores with 1 to 4 polar filaments ♠ Many nuclei in adult tropozoite class Myxosporidia Microsporidea 1. Spores enclosed in two or three 1. Parasitic in arthropods and valves fishes 2. Spores developed from several 2. Only one or two polar filaments nuclei present Eg. Myxidium 3. Spores small with a univalved Myxobolus membrane Eg. Nosema (causes disease in silkworm, honey bee) 56 Dr Puja Ray 28  9/17/2024 Phylum Protozoa- Classification Sub-phylum Ciliophora ♠ Locomotory organs cilia, present either through out life or in young condition. ♠ Two types of nuclei- mega and micro. ♠ Asexual reproduction by binary fission or budding. ♠ Sexual reproduction by conjugation ♠Alternation of generation absent class Ciliata 1. Locomotory organelles –numerous cilia 2. One or more contractile vacoules present Vorticella 3. Nutrition –holozoic 4. Nuclear dimorphism Eg. Vorticella, Paramecium, 5. Reproduction Balantidium, Ephelota, Didinium Asexually by binary fission Sexually by conjugation 6. Only pathogenic ciliate – Balantidium coli 57 In protozoa contractile vacuole is generally absent in the class: a. Rhizopoda, b. sporozoa, c. ciliata, d. flagellata The main basis of classification of phylum protozoa is: Size, b. locomotory organelle, c. shape, d. no of nuclei 58 Dr Puja Ray 29  9/17/2024 Phylum – Porifera The Sponges Pori= pore; Fera= to bear 59 1. Phylum Porifera - The Sponges: Porifera means "pore-bearing"; their sac-like bodies are perforated by many pores. a.) Habitat: mainly marine (salt water) b.) Sponges have a porous body wall. The pores or holes allow water to pass through this animal. Floating food particles are caught once they are inside the sponge. c.) Skeleton made of network of protein fibers called Spongin Examples: Tube Sponge, Glass Sponge, Sea Sponge 60 Dr Puja Ray 30  9/17/2024 Sponge Skeletons Silica Spicules Limestone Spicules SPONGIN 61 1. Phylum Porifera - The Sponges: Examples: Tube Sponge, Glass Sponge, Sea Sponge d.) Adult sponges are sessile feeders which means these animals are attached to shells or rocks on the ocean floor as they feed. e.) reproduce by fragmentation (pieces break off & form a new sponge) f.) Shape: asymmetrical (which means no definite shape). g.) Free-swimming larval stage - coeloblastula larvae (= blastula larvae), parenchymula (= parenchymella), amphiblastula. coeloblastula larvae 62 Dr Puja Ray 31  9/17/2024 Phylum Porifera - The Sponges: h) Inside body cavity of sponge is hollow called the Spongocoel i) Have 2 cell layers:  Outer epidermis  Inner endoderm Jelly-like material between cell layers called mesohyl or mesenchyme 63 Canal system Water Flow Through the WATER OUT Sponge: Water enters through many small pores called ostia and exits through fewer, larger oscula. (Ostium) Osculum WATER IN 64 Dr Puja Ray 32  9/17/2024 There are three types of canal systems Asconoid is the most simple body type of sponges and typically the smallest Sycanoid is the intermediate in size and complexity Leuconoid is the largest type of sponge and the most complex 65 66 Dr Puja Ray 33  9/17/2024 Phylum Porifera 67 Classification of Phylum Porifera Phylum Porifera Class Calcarea Class Hexactinellida Class Demospongiae 68 Dr Puja Ray 34  9/17/2024 Class Calcarea (Calcispongiae) L. Calarius= limy small sized calcareous sponges with spicules of calcium carbonate, below 10 cm ht., solitary or colonial. The spicules are straight or have three or four rays. Body shaped cylindrical or vase-like. Skeleton of separate one or three or four rayed calcaerous spicules. Body organization of asconoid, syconoid or leconoid type Exclusively marine Eg: Leucosolenia, Sypha (= Sycon), Grantia Leucosolenia Sycon 69 Class Hexactinellida Gr. Hex= six; actin= ray; ella =terminal + -ida the glass sponges Occurs mostly in syconoid form Moderate sized glass sponges, some reach one metre length. Body shaped cup, urn or vase-like. Skeleton of six-rayed triaxon siliceous spicules Choanocytes restricted to finger shaped chambers. Exclusively marine, mainly in deep see. Eg: Euplectella (Venus flower basket), Hyalonema (glass rope sponge). 70 Euplectella Hyalonema Dr Puja Ray 35  9/17/2024 Class Demospongiae Gr. demas= frame; spongos= sponge contains 95% of living sponge species. Small to large sized, solitary or colonial Body shaped like vase, cup or cushion. Skeleton of siliceous spicules or spongin fibres or both or absent. Spicules monoaxon, tetraxon, never triaxon All are leuconoid and all are marine except for Spongillidae, the freshwater sponges. Body organization leuconoid. Choanocytes restricted to small rounded chambers. Mostly marine. Eg: Euspongia (=Spongia bath sponge), Spongilla, Cliona (Boring sponge), Geodia. 71 Euspongia Spongilla Figure 12.15 72 Dr Puja Ray 36  9/17/2024 73 Phyla Cnidaria and Ctenophora Ctenophores and cnidarians were formerly placed together in the phylum Coelenterata. Modern authorities, however, have separated the cnidarians and ctenophores on the basis of the following ctenophore characteristics: (1) the lack of the stinging cells (nematocysts) that are characteristic of cnidarians (2) the existence of a definite mesoderm in the ctenophores (3) fundamental differences in embryological development between the two groups (4) the biradial symmetry of ctenophores. (5) however, ctenophores and cnidarians possibly share a common evolutionary ancestor 74 Dr Puja Ray 37  9/17/2024 Cnidaria Ctenophora 75 Characteristics Cnidarians Ctenophores symmetry exhibit radial exhibit biradial symmetry symmetry stinging cells present absent (nematocysts) diversity highly diversified animals less diversity habitat live in both freshwater exclusively in marine and marine habitats alteration of show; does not show; generations possess both polyp and only possess the medusa stage medusa stages. sessile/swimming sessile or free-swimming swim by the comb plates digestive system incomplete complete sex either unisexual or hermaphrodites hermaphrodites 76 Dr Puja Ray 38  9/17/2024 77 Phylum Coelenterata (Cnidaria) Hydra, jellyfish, coral, & sea anemones 78 Dr Puja Ray 39  9/17/2024 2. Phylum Coelenterata (Cnidarians): a.) Habitat: mostly marine b.) Body wall: Diploblastic- body wall is made of 2 cell layers called the ectoderm and endoderm. A jelly like material, mesohyl (mesoglea) is found between these 2 layers. c.) Digestive System: The digestive system is incomplete - have just one opening to the digestive cavity. Mouth is the only body opening and is surrounded by tentacles. d.) Body cavity known as coelenteron present. e.) Symmetry: radial f.) acoelomate Jellyfish 79 Portuguese Man-O-War (Physalia) Hydra Phylum Coelenterata (Cnidarians): g.) Specialized Cells: 1. Most coelenterates have tentacles that contain stinging cells that are used for protection and capturing food. 2. Their bodies contain a nerve network that allows movement of the tentacles and body. 80 Dr Puja Ray 40  9/17/2024 Tentacles Have nematocysts (stinging cells) Coiled thread discharges like a harpoon Contains neurotoxin Paralyzes prey Discharged nematocyst 81 82 Dr Puja Ray 41  9/17/2024 I. Body Structure h.) Present in two forms: polyp (sessile) and medusae (free- swimming). Several are polymorphic. Polymorphism = more than one body form 83 1. Polyp Tube with tentacles around the mouth Sessile Coral polyp 84 Dr Puja Ray 42  9/17/2024 Polyp forms Polyp (sea anemone) 85 Mythical Hydra Perseus slays the Gorgon Medusa 86 Dr Puja Ray 43  9/17/2024 2. Medusa Umbrella shape Tentacles around mouth Motile, Free-swimming 87 88 Dr Puja Ray 44  9/17/2024 Phylum- Cnidaria 3 Major classes Class Hydrozoa: Hydra, Obelia, Physalia Class Scyphozoa: Jellyfish (Aurelia) Class Anthozoa: Anemones and corals 89 Class Hydrozoa (hydra= water; zoon= animal) Fresh water or marine, solitary or colonial Alternation of generation between asexual polyp (as the dominant body plan) and sexual medusae present. Often only polyp present Incomplete digestive with an unbranched gut. Mesoglea thin and non-cellular Medusa with a true velum 90 Hydra Dr Puja Ray 45  9/17/2024 Alternation of generation in Obelia 91 Class Scyphozoa (Gk: Skyphos= drinking cup, Latin: zoon= animal) Exclusively marine, solitary Alternation of generation with medusa the dominant body plan. Polyp stage reduced or absent Incomplete digestive with four branches Mesoglea thick with some cells Medusa without velum Eg. Tubipora, Aurelia Lion’s Mane Jelly (Cyanea capillata) Aurelia aurita (Moon jelly) 92 Dr Puja Ray 46  9/17/2024 Class Anthozoa (Actinozoa) (Flower-like animals) Exclusively marine, solitary or colonial No alternation of generation - polyps only Incomplete digestive with 6 to 8 branches (septia) Nematocyst in the gut (acontia) Mesoglea thick and with muscle tissue eg: Coral Reefs, Metridium (sea anemone) Rosy Sea Anemone Brain coral Tubipora 93 Class Anthozoa Genus — Gorgonia Sea fan 94 Dr Puja Ray 47  9/17/2024 Phylum Ctenophora Gr. cten = comb, phoros = to bear) Most species live in the open ocean and are not well studied Beroe 95 Phylum: Ctenophora commonly known as sea walnuts or comb jellies. marine, solitary, free-swimming or pelagic. body transparent and delicate. Stringing predators. symmetry : biradial along with oral-aboral surface. three germ layers (epidermis, gastrodermis, mesoglea if included). Digestive system consists of mouth, pharynx, stomach with a canal system and aboral anal pores. Nematocysts absent. Instead have special adhesive and sensory cells called colloblasts present on tentacles, help in food capture. Have no CNS or brain, but a nerve net. Use an aboral sense organ with a statocyst to maintain balance. Most ctenophores are capable of bioluminescence, which is quite faint and only visible in darkened conditions All Ctenophores have a distinct larval form before adulthood – cydippid larva. 96 Monoecious (hermaphrodite). Dr Puja Ray 48  9/17/2024 Phylum Ctenophora class Tentaculata Microsporidea Body rounded or oval Ctenophora without tentacles Tentacles branched, retractile into pouches Eg. Beroe Eg. Pleurobrachia Hormiphora Pleurobrachia Beroe 97 The sea gooseberry (Pleurobrachia bachei) is a plankton-eating predator that uses its tentacles to catch prey 98 Dr Puja Ray 49  9/17/2024 Phylum – PLATYHELMINTHES The flat worms 99 Phylum Platyhelminthes – The Flatworms: planaria, tapeworms (Platy = flat; Helmins= worm) Flat thin bodies Bilateral symmetry Triploblastic, aceolomate Digestive system has only one opening Hermaphrodites or asexual Mostly parasites 100 Dr Puja Ray 50  9/17/2024 3. Phylum Platyhelminthes – a.) Habitat: fresh and salt water; terrestrial (land) b.) Body Plan: These animals are given their name because of their flattened bodies. Flatworms have 3 distinct tissue layers called the ectoderm, endoderm, and mesoderm. Each layer gives rise to the various organs and systems of this animal. c.) Digestive System: In free-living species of flatworms the digestive system is incomplete which means that the digestive cavity has only a single opening. The parasitic tapeworm has no need for a digestive system because it absorbs nutrients that are already digested by the host in which it lives. d.) Symmetry: Flatworms have bilateral symmetry and they have a definite head and tail region. e.) Specialized Structures: 1. The planaria has a pair of eyespots at its anterior or front end. These eyespots detect light which the planaria avoids so they are less visible to their predators. 2. The tapeworm like other parasitic worms has a thick protective cuticle on the outside of its body. The cuticle protects the worm from being digested by the strong digestive enzymes of its host. 101 Flatworms: Platyhelminthes f. The flatworms are the first organisms to possess some form of organ. These organs are simple kidneys called nephridia and are mesodermal in tissue origin as all organs are. g. The flatworms are capable of directed movement and thus have nerves and the concentration of nervous tissue in the head region, which is called cephalization. h. Cephalization and bilateral symmetry facilitate movement towards and away from stimuli. i. The size of an individual flatworm is limited by the fact that it has no respiratory or circulatory system and all exchange of gases occurs through the skin through the process of diffusion. j. The body is paper thin to bathe all of the cells in oxygen. k. Because of these limitations most flatworms have taken on a parasitic existence where they exist off the nutrients produced by other organisms. 102 Dr Puja Ray 51  9/17/2024 Regeneration Many species posses remarkable powers of regeneration and repair wounds 103 Dugesia sp Fasciola hepatica 104 Dr Puja Ray 52  9/17/2024 Platyhelminthes Taxonomy Class Turbellaria – Free living, marine planarians & marine flatworms Class Trematoda – Internal Flukes- Fasciola Class Monogenea All Parasitic – External Flukes- fish gills – eg. Diclidophora Class Cestoda – Tapeworms – intestinal parasites- eg. Taenia 105 Class Turbellaria Free-living flatworms; mostly marine organisms Range in size from microscopic (interstitial species between sand grains) to extremely large (two feet) Locomotion Most move by means of cilia and mucous Muscle contractions also permit turning, twisting and folding of the body Eg Planaria 106 Dr Puja Ray 53  9/17/2024 Class Turbellaria con’t…. Nutrition Turbellarians are carnivores and prey on other animals or eat dead animal remains. Planarians have a muscular pharynx that they can insert into their prey and then pump to bring in food fragments These animals have a highly divided gut to greatly increase the surface area for digestion and absorption Senses They have well developed sensory structures, including eyespots, mechanoreceptors, and chemoreceptors 107 Class Turbellaria con’t…. Reproduction Planarians are capable of asexual reproduction via fission Also capable of regeneration; exhibit both anterior- posterior and lateral polarity They are hermaphrodites but usually exhibit cross-fertilization The penis of some turbellarians is modified as a hollow stylet; sperm tranfer is by hypodermic impregnation, in which the copulating partners stab each other and inject sperm 108 Dr Puja Ray 54  9/17/2024 Class Trematoda Flukesthat live as parasites either on or in other organisms. Outer body lacks cilia; tegument has a layer of glycoproteins that are important in protection and absorption Possess 2 suckers: 1. Oral sucker which attaches to organs of the host 2. Ventral sucker or acetabulum; used to attach to host tissues 109 Types of Hosts Often have complex life cycles that alternate between sexual and asexual stages. Most require at least 2 different kinds of hosts to complete their life cycle: 1. Definitive host (primary host) The host in which the parasite matures and reproduces (sexually) The host in which eggs are released 2. Intermediate host Hosts in which larval stages develop and undergo asexual reproduction Results in an increase in the number of the individuals 110 Dr Puja Ray 55  9/17/2024 General Life Cycle - Chinese liver fluke, Clonorchis sinensis Adults live in the bile ducts of humans, dogs, and cats (Definitive host) There are 2 intermediate hosts: a snail and a fish Eggs are passed out of the definitive host and hatch as ciliated larvae called miracidia The miracidia penetrates a snail molluscan host and becomes a sporocyst They undergo asexual reproduction producing larvae called rediae Rediae often asexually produce more rediae, but will eventually give rise to larvae called cercariae They leave the molluscan host and penetrate fish They encyst in the fish tissues as the metacercaria Consumption of infected fish results in the metacercaria excysting in the gut and migrating to the bile duct 111 112 Dr Puja Ray 56  9/17/2024 Schistosoma Schistosoma spp. is a common blood fluke of Southeast Asia that causes shistosomiasis Humans are the definitive host; snails are the intermediate host In humans its eggs ultimately penetrates and damages intestinal tissue and tissue of the bladder A source of constant inflammation and eventually leads to deterioration of liver, spleen and other organs 113 Class Cestoda General Morphology Non-ciliated tegument composed of glycoprotein The anterior region is called a scolex; often armed with suckers and hooks Extending from the neck is a series of proglottids; contain the sex organs and eggs; no digestive system Mature eggs released through an opening in the proglottid or leave the host when the proglottids are separated from the main body of the worm. 114 Dr Puja Ray 57  9/17/2024 Beef Tapeworm, Taeniarhynchus saginatus Definitive host humans; intermediate host cattle Eggs are shed with human feces; infected persons defecate in a pasture and the eggs are ingested by cattle Eggs hatch giving rise to oncosphere larvae that bore into the intestinal wall and get into the circulatory system to be transported to muscle Here the larvae develop into the cysticercus stage (=the bladder worm) with the inverted scolex If uncooked beef is consumed the cysticercus is freed and the scolex everts, forming the adult Symptoms include loss of weight, chronic indigestion, diarrhea 115 116 Dr Puja Ray 58  9/17/2024 Phylum – Aschelminthes (Gk askos = sac + helminth = 'worm' ) 117 Phylum Aschehelminthes HABIT AND HABITAT wide distribution and exists in almost every habitat. Free living nematodes are found in the sea, fresh water or in the soil in all kinds of environment. There are also many parasitic nematodes found in all groups of plants and animals. The Saprophagous species live in decomposing plant and animal bodies and in rotting fruits. 118 Dr Puja Ray 59  9/17/2024 Phylum Aschelminthes Mostly parasitic (in animals and plants), a few free living called as flukes. Body is long, cylindrical, fusiform (pointed at both the ends). Body wall is composed of cuticle, epidermis and musculature. Presence of a false body pseudocoelom not Ascaris lined by epithelium. Digestive system is complete. Respiration by simple diffusion. Nervous system consists of a nerve ring and many longitudinal nerve cords. Only sexual reproduction. Sexes are separate with sexual dimorphism. Males are usually shorter Woucheria than females 119 Phylum – Annelida (Latin: annulus = a ring; Greek: edios=form) 120 Dr Puja Ray 60  9/17/2024 Phylum Annelida Bilaterally symmetrical and vermiform. Body has more than two cell layers, tissues and organs. Body cavity is a true coelom, often divided by internal septa. Body possesses a through gut with mouth and anus. Body possesses 3 separate sections, a prosomium, a trunk and a pygidium. The body is triploblastic with a well developed coelom. The body covered with a flexible non-chitinous cuticle. Digestive tract complete, usually with regional specialization. Has a nervous system with an anterior nerve ring, ganglia and a ventral. nerve chord. Has a true closed circulatory system. Has no true respiratory organs. Reproduction normally sexual and gonochoristic or hermaphoditic. Feed on wide range of material. Live in most environments. 121 Annelids occur worldwide, found in the sea, freshwater, and in the soil. They feed on organic matter in the mud or soil, by filtering suspended particles from the water, act as predators, or suck blood. 122 Dr Puja Ray 61  9/17/2024 Annelid Characteristics Defining Characteristics – One or more pairs of chitinous setae – exhibits true segmentation (metamerism) The phylum includes polychaetes, earthworms, leeches, and vestimentiferans 123 Segmentation Their body exhibits true segmentation (metamerism). Within each segment are components of most organ systems such as the circulatory, nervous and excretory systems. Thus, there is a degree of redundancy in annelids so that if a segment is damaged it need not be fatal. 124 Dr Puja Ray 62  9/17/2024 Locomotion On each side its segments there is a parapod (parapodia) consisting of fleshly lobes, which are supported by chitinous rods. Each parapod have setae, which can be sharp (protection), and aid in locomotion. usually powerful, pincher like jaws: (sandworms and clamworms). 125 Feeding Annelids range from carnivores, herbivores, scavengers, deposit feeders, filter feeders and parasites. With very few defenses, many remain in a burrow or secreted tube. Carnivores can capture prey with strong jaws and quickly drag it back to its burrow. – Can use a muscular pharynx = eversible proboscis 126 Dr Puja Ray 63  9/17/2024 127 Digestive System 128 Dr Puja Ray 64  9/17/2024 Circulatory System Blood flows entirely in closed vessels Some spp. have hearts Blood contains hemoglobin, which increases oxygen carrying ability 129 Excretory & Nervous System Nervous system 130 Dr Puja Ray 65  9/17/2024 Reproductive System Most annelids are hermaphroditic, but they are usually cross fertilizers. Earthworms and leeches form pairs and reciprocally fertilize one another Some annelids (e.g. marine sandworms) are dioecious and they release eggs and sperm into the marine environment, where gametes unite to form trochophore larvae Fertilization can be internal or external Trochophore larvae develop, which are remarkably similar to the Molluscs. 131 Classes of Annelida Class Polychaeta (fanworms, clam worms) Class Oligochaeta (earthworms) Class Hirudinea (Leeches) 132 Dr Puja Ray 66  9/17/2024 Annelid Phylogeny 133 Class - Polychaeta (Gr., poly=many + chaite= bristles) Feather Duster worms, Clam worms, Christmas Tree worms Dr Puja Ray Nereis 134 67  9/17/2024 Class - Polychaeta General Characteristics Mostly marine and free-living Many setae, on fleshy lateral outgrowths of the body wall known as parapodia Clitellum absent Well developed head bearing appendages Sexes separate, with a free-swimming trochophore larva 135 136 Dr Puja Ray 68  9/17/2024 Class - Polychaeta Parapodia 137 Polychaeta Lugworm (Arenicola sp) 138 Dr Puja Ray 69  9/17/2024 sea mouse, Aphrodita 139 Class Oligochaeta (Gr., Oligos=few, Chaite= bristles) Earthworms and Freshwater Worms 140 Dr Puja Ray 70  9/17/2024 Class Oligochaeta General Characteristics Mostly terrestrial, few freshwater species Have few setae No parapodia No distinct head appendages Clitellum present Hermaphrodites, with copulation required Eggs are deposited in a cocoon and development is direct 141 Figure 17.17 142 Dr Puja Ray 71  9/17/2024 143 Class Hirudinea (L., Herudo= leach) 144 Dr Puja Ray 72  9/17/2024 Class Hirudinea General Characteristics Ectoparasites, not all - many feed on organic debris Usually dorso-ventrally flattened with fixed number of body segments (32) Segmentation external, but no internal septa No setae or parapodia Two suckers – anterior and posterior Anterior segments are modified as a small sucker which surrounds the mouth; posterior segments form a larger sucker Clitellum present only during reproduction Hermaphrodite 145 Figure 17.20 146 Dr Puja Ray 73  9/17/2024 147 Dr Puja Ray 74