1.PART I

2. KINGDOM LEVEL OF ORGANIZATION SYMMETRYCOELOM PHYLUMCELLULARPorifereaLEVELCnidariaCtenophora RADIALPlatyhelminthes ANIMALIA Acoelomates Aschelminthe sTISSUE / ORGAN/ Pseudoco Annelida ORGAN SYSTEM BILATERAL LEVEL elomatesArthropodaCoelomates Mollusca Echinodde rmata Hemichordata Chordata 3. When you look around, you will observe different animals withdifferentstructures and forms. As over amillion species of animals have beendescribed till now, the need forclassification becomes all the more important. The classification also helps in assigning a systematic position to newly described species. 4. Shall we learn thebasis ofclassificat ionDidnt get me Sorry thats mylanguage!!! 5. Shall we try tounderstand thebasis ofclassification? Now you got it.!!! 6. BASIS OF CLASSIFICATION Inspite of differences in structure and form of different animals, there are fundamental features common to variousindividuals in relation to thearrangement of cells, body symmetry, nature ofcoelom, patterns of digestive, circulatory or reproductive systems. 7. Levels of OrganisationThough all members of Animalia are multicellular, all of them do notexhibit the same pattern of organisation of cells. For example, in sponges,the cells are arranged as loose cell aggregates, i.e., they exhibit cellularlevel of organisation. Some division of labour (activities) occur amongthe cells. In coelenterates, the arrangement of cells is more complex. Herethe cells performing the same function are arranged into tissues, hence iscalled tissue level of organisation. A still higher level of organisation, i.e.,organ level is exhibited by members of Platyhelminthes and other higherphyla where tissues are grouped together to form organs, each specialisedfor a particular function 8. In animals likeAnnelids, Arthropods, Molluscs,Echinodermsand Chordates, organs have associated to form functional systems, eachsystem concerned with a specific physiological function. This pattern is called organ system level of organisation 9. A complete digestive system hastwo openings, mouth and anus. Similarly, thecirculatory system may be of two types:(i) open type in which the blood is pumpedout of the heart and the cells and tissues aredirectly bathed in it or(ii) closed type in which the blood is circulatedthrough a series of vessels of varying diameters(arteries, veins and capillaries). 10. Symmetry Animals can be categorised on the basisof theirsymmetry. Sponges are mostly asymmetrical,i.e., any plane that passesthrough the centredoes not divide them into equal halves. 11. Radial symmetryWhen any plane passingthrough the central axis ofthe body divides theorganism into two identicalhalves, it is called radialsymmetry.Coelenterates, ctenophoresand echinoderms have thiskind of body plan 12. Bilateral symmetryAnimals like annelids, arthropods, et c., wherethe body can be divided into identical left andright halves in only one plane, exhibit bilateralsymmetry 13. Diploblastic and TriploblasticOrganisationAnimals in which the cells are arranged in twoembryonic layers, an external ectoderm andan internal endoderm, are called diploblasticanimals, e.g., coelenterates. An undifferentiatedlayer, mesoglea, is present in between theectoderm and the endoderm 14. Those animals in which thedeveloping embryo has athird germinallayer, mesoderm, inbetween the ectodermand endoderm, are calledtriploblastic animalsplatyhelminthes tochordates 15. CoelomPresence or absence of a cavity between the bodywall and the gut wall is very important inclassification. The body cavity, which is linedby mesoderm is called coelom. 16. Animalspossessing coelom arecalled coelomates, e.g.,annelids, molluscs, arthropods, echinoderms,hemichordates andchordates 17. In some animals, the body cavityis not lined bymesoderm, instead, themesoderm is present asscattered pouches in between theectoderm andendoderm. Such a body cavity iscalledpseudocoelom and the animalspossessing themare calledpseudocoelomates, e.g.,aschelminthes 18. The animals in which the body cavity isabsent are called acoelomates, e.g., platyhelminthes 19. Segmentation In some animals, thebody is externally andinternally divided into segments with a serialrepetition of at leastsome organs. Forexample, in earthworm, the bodyshows this pattern calledmetameric segmentation and the phenomenon isknown as metamerism. 20. NotochordNotochord is a mesodermally derived rod-like structure formed on thedorsal side during embryonic development in some animals. Animals withnotochord are called chordates and those animals which do not form thisstructure are called non- chordates, e.g., porifera to echinoderms. 21. CLASSIFICATION OF ANIMALS 22. Members of this phylum are commonly known as sponges.They are generally marine and mostly asymmetrical animals .These are primitive multicellular animals and have cellular level of organisation.Sponges have a water transport or canal system.Water enters throughminute pores (ostia) in the body wall into a centralcavity, spongocoel, from where it goes out through the osculum. 23. This pathway of water transport is helpful in foodgathering, respiratory exchange and removal of waste. Choanocytes or collar cells line the spongocoel and thecanals.Digestion is intracellular.The body is supported by a skeleton made up of spiculesor spongin fibres.Sexes are not separate (hermaphrodite), i.e., eggs andsperms are produced by the same individual. 24. Sponges reproduce asexually byfragmentation and sexually by formation ofgametes. Fertilisation is internal and developmentis indirect having a larval stage which ismorphologically distinct from the adult. Examples: Sycon (Scypha), Spongilla (Fresh water sponge) and Euspongia (Bath sponge). 25. Photo AlbumSponges 26. sponge sponge 27. sponge sponge 28. sponge sponge 29. They are aquatic, mostly marine, sessile or free-swimming, radially symmetrical animals The namecnidaria is derived from the cnidoblasts or cnidocytes(which contain the stinging capsules or nematocytes)present on the tentacles and the body.Cnidoblasts are used for anchorage, defense and for thecapture of prey Cnidarians exhibit tissue level oforganisation and are diploblastic.They have a central gastro-vascular cavity with a singleopening, hypostome. Digestion is extracellular andintracellular. Some of the cnidarians, e.g., corals havea skeleton composed of calcium carbonate. 30. Cnidarians exhibit two basic body forms calledpolyp and medusa .The former is a sessile and cylindrical form likeHydra, Adamsia, etc. whereas, the latter isumbrella-shaped and free-swimming like Aureliaor jelly fish.Those cnidarians which exist in both forms exhibitalternation ofgeneration(Metagenesis), i.e., polyps produce medusaeasexually and medusae form the polyps sexually(e.g., Obelia). 31. Diagrammatic view ofCnidoblast (a) Aurelia (b) Adamsia(Medusa)(Polyp)Examples of Coelenterata indicating outline of their body form :(a) Aurelia (Medusa) (b) Adamsia (Polyp) 32. Examples: (photo Album) Physalia (Portuguese man-of-war), Adamsia(Sea anemone), Pennatula (Sea-pen), Gorgonia (Sea-fan) andMeandrina (Brain coral).PHOTO ALBUM 33. CNIDARIANS 34. seapen2 star coral 35. star corals 01CORAL 36. 1coral 02CORAL 37. 2coral 05CORAL 38. 08coral 09CORAL 39. Amemoe Anemone 40. anemone2 brain coral 41. common anemone Coral 42. Coral1 Coral2 43. Obelia7 1aurelia strobila 44. 1hydra 1pennaria 45. 1physalia 4Physalia 46. 6Physalia 7Hydra 47. 7Physalia 10gorgonia 48. 10Physalia 11Physalia 49. 12Physalia 13Physalia 50. fungia1 fungia2 51. fungia3 Obelia1 52. Obelia2 Obelia3 53. Obelia4 Obelia5 54. Obelia6 55. Phylum Ctenophora 56. Ctenophores, commonly known as sea walnutsor comb jellies are exclusivelymarine, radially symmetrical, diploblasticorganisms with tissue level of organisation.The body bears eight external rows of ciliatedcomb plates, which help in locomotion 57. Digestion is both extracellular and intracellular.Bioluminescence (the property of a livingorganism to emit light) is well-marked inctenophores.Sexes are not separate. Reproduction takes placeonly by sexual means.Fertilisation is external with indirectdevelopment. 58. Examples:Pleurobrachia andCtenoplana. 59. PHYLUM PLATYHELMINTHES 60. They have dorso-ventrally flattened body, henceare called flatworms .These are mostly endoparasites found in animalsincluding human beings.Flatworms are bilaterallysymmetrical, triploblastic and acoelomateanimals with organ level of organisation.Hooks and suckers are present in the parasiticforms.Some of them absorb nutrients from the hostdirectly through their body surface. 61. Specialised cells calledflame cells help in osmoregulation and excretion.Sexes are notseparate. Fertilisation is internal and development isthrough many larval stages.Some members like Planaria possess high regeneration capacity. 62. PLATYHELMINTES 63. lfluke1 lfluke2 64. lfluke3 taenia 65. taenia1 tape1 66. tape2 tape3 67. tape4 TAPEWORMn1 68. TAPEWORMn2 69. Phylum AschelminthesAschelminthes Roundworm 70. The body of the aschelminthes is circular incross-section, hence, the name roundworms.They may be free living, aquaticand terrestrial or parasitic in plants and animals.Roundworms have organ-system level of bodyorganisation 71. They are bilaterally symmetrical,triploblastic and pseudocoelomate animals.Alimentary canal is complete with a welldevelopedmuscular pharynx. An excretorytube removes body wastes from the body cavitythrough the excretory pore. Sexes are separate(dioecious), i.e., males and females are distinct.Often females are longer than males. Fertilisationis internal and development may be direct (theyoung ones resemble the adult) or indirect. 72. Ascaris (Round Worm), Wuchereria(Filaria worm), Ancylostoma (Hookworm). 73. Photo AlbumRound worms 74. Phylum Annelida (a) Nereis (b) Hirudinaria 75. They may be aquatic (marine and fresh water)or terrestrial; free-living, and sometimesparasitic. They exhibit organ-system level ofbody organisation and bilateral symmetry. Theyare triploblastic, metamerically segmented andcoelomate animals. Their body surface isdistinctly marked out into segments ormetameres (Latin, annulus : little ring) and,hence, the phylum name Annelida 76. They possess longitudinal and circular muscles which help in locomotion. Aquatic annelids likeNereis possess lateral appendages, parapodia,which help in swimming. A closed circulatory system is present. Nephridia (sing. nephridium)help in osmoregulation and excretion. Neuralsystem consists of paired ganglia (sing. ganglion) connected by lateral nerves to a double ventralnerve cord. Nereis, an aquatic form, is dioecious,but earthworms and leeches are monoecious.Reproduction is sexual 77. Examples : Nereis, Pheretima (Earthworm)and Hirudinaria (Blood sucking leech) 78. ANNELIDA 79. PHYLUM ARTROPODA(a) Locust (b) Butterfly(c) Scorpion (d) Prawn 80. This is the largest phylum of Animalia whichincludes insects. Over two-thirds of all namedspecies on earth are arthropods .They have organ-system level of organisation.They are bilaterally symmetrical, triploblastic,segmented and coelomate animals. The bodyof arthropods is covered by chitinousexoskeleton. The body consists of head, thoraxand abdomen. 81. They have jointed appendages(arthros-joint, poda-appendages). Respiratory organs are gills, book gills, book lungs ortracheal system. Circulatory system is of open type. Sensory organs like antennae, eyes(compound and simple), statocysts or balance organs are present. Excretion takes place through malpighian tubules. They are mostly dioecious. Fertilisation is usually internal.They are mostly oviparous. Development maybe direct or indirect. 82. Examples: Economically important insects Apis (Honey bee), Bombyx (Silkworm), Laccifer(Lac insect)Vectors Anopheles, Culex and Aedes(Mosquitoes)Gregarious pest Locusta (Locust)Living fossil Limulus (King crab). 83. ARTHROPODAPHOTO ALBUM 84. Phylum Mollusca(a) Pila (b) Octopus 85. This is the second largest animal phylum.Molluscs are terrestrial or aquatic (marine or fresh water) having anorgan-system level of organisation. They arebilaterally symmetrical, triploblastic andcoelomate animals. Body is covered by acalcareous shell and is unsegmented with adistinct head, muscular foot and visceral hump. 86. A soft and spongy layer of skin forms amantle over the visceral hump. The spacebetween the hump and the mantle is called themantle cavity in which feather like gills arepresent. They have respiratory and excretoryfunctions. The anterior head region has sensorytentacles. The mouth contains a file-likerasping organ for feeding, called radula. 87. They are usually dioecious and oviparous withindirect development.Examples: Pila (Apple snail), Pinctada (Pearloyster), Sepia(Cuttlefish), Loligo (Squid), Octopus (Devilfish), Aplysia (Seahare),Dentalium (Tusk shell) and Chaetopleura(Chiton). 88. by ROYPHOTO ALBUM 89. loligo1 loligo2 90. lsnail03 lsnail04 91. Mytilus2 Mytilus3 92. Nautilus nautilus_nm 93. OCTOPUS1 Octopus2 94. octopus_n1 octopus_nm 95. Text Boxzebra mussel 96. (a) Asterias(b) Ophiura 97. These animals have an endoskeleton of calcareousossicles and, hence, the name Echinodermata(Spiny bodied). All are marine with organ-systemlevel of organisation.The adult echinoderms are radially symmetricalbut larvae are bilaterally symmetrical.They are triploblastic and coelomate animals.Digestive system is complete with mouth on thelower (ventral) side and anus on the upper(dorsal) side. 98. The most distinctive feature of echinoderms is thepresence of water vascular system which helps inlocomotion, capture and transport of food andrespiration.An excretory system is absent. Sexes are separate.Reproduction is sexual. Fertilisation is usuallyexternal.Development is indirect with free-swimming larva. 99. Examples: Asterias (Star fish), Echinus (Seaurchin), Antedon (Sea lily), Cucumaria (Sea cucumber) andOphiura (Brittle star). 100. ECHINODERMATA 101. 3starfish- 6starfish- 102. 13starfish- 15starfish- 103. 16starfish- 17starfish- 104. bg_star Brittlestarnn2 105. brittlestarnn3 starfish 106. STARFISH1 STARFISH3 107. STARFISH4 STARFISH6 108. Phylum HemichordataBalanoglossus 109. Hemichordata was earlier considered as asub-phylum under phylum Chordata. But nowit is placed as a separate phylum under non-chordata. 110. This phylum consists of a small group of worm-likemarine animals with organ-system level of organisation. They are bilaterally symmetrical, triploblastic and coelomate animals.The body is cylindrical and is composed of ananterior proboscis, a collar and a long trunk .Circulatory system is of open type.Respiration takes placethrough gills. Excretory organ is proboscis gland. Sexes areseparate. Fertilisation is external. Development is indirect.Examples: Balanoglossus and Saccoglossus. 111. Plz send me an sms for the part II Roy Augustine .Zoology teacher, St. MichaelsAnglo Indian School Kannur 09388200676