Animal Kingdom and Classification, Summaries of Biology

Download Animal Kingdom and Classification and more Summaries Biology in PDF only on Docsity! Animals are multicellular and heterotrophic. Animal kingdom is most diverse than the plant kingdom. Based on the organization of the cells, there are 3 levels of organization Cellular level of organization: Cells are arranged as loose cell aggregates. E.g. sponges Tissue level of organization: Cells are arranged into tissues. E.g. coelenterates, ctenophores Organ level of organization: Tissues are arranged into organs and the organs are associated to form organ systems. Each system performs a specific physiological function. E.g. All higher animals (from platyhelminthes to chordates). Organ systems of different animals show complexities. For example, The digestive system of cnidarians and platyhelminthes is incomplete (only a single opening functioning as mouth and anus). Complete digestive system has 2 openings (mouth and anus). Circulatory system is 2 types (open and closed). It is the arrangement of similar body parts on 2 sides of main axis of body. Based on symmetry, animals are 2 types: Symmetry is 2 types: Radial symmetry Bilateral symmetry Radial symmetry: Body can be divided into 2 similar parts by any plane along oral- aboral axis of body. E.g. some Sponges, Coelenterates, Echinoderms. Bilateral symmetry: Body can be divided into 2 right and left halves by a section passing through the longitudinal axis. E.g. All vertebrates and many invertebrates. Such animal has An upper or vertebral dorsal side A lower ventral side Left and right lateral sides Anterior (cephalic) side and Posterior (anal) side. Levels of organisation Germ layers Symmetry Coelom Phylum Cellular level Diploblastic Asymmetrical / radial Acoelomate Porifera Tissue Diploblastic Radial Acoelomate Cnidaria Ctenophora Organ/ Organ system Triploblastic Bilateral Acoelomate Platyhelminthes Pseudocoelomate Aschelminthes Coelomates Annelida Arthropoda Mollusca Echinodermata Hemichordata Chordata Habit: Aquatic. Sedentary. Solitary or colonial. Digestive system: Absent. Digestion is intracellular. Water transport (canal system) to gather food. Respiratory system: Absent. Respiration by canal system. Circulatory system: Absent. Circulation by canal system. Excretory system: Absent. Excretion by canal system. Nervous system: Absent Reproductive system: Hermaphrodite. ARP by fragmentation. SRP by the formation of sperms and ova. Fertilization internal. Development is indirect. Other features: Millions of minute pores (ostia). Body wall with outer layer of flat cells (pinacocytes) and inner layer of flagellated cells (choanocytes or collar cells). Body is supported by spicules & spongin fibres. Highest degree of regenerating capacity. Habit: Aquatic. Solitary or colonial. Sessile or free swimming. Digestive system: Incomplete. Intracellular and extracellular digestion. Respiratory system: Absent Circulatory system: Absent Excretory system: Body surface Nervous system: Only a network of neurons. Reproductive system: Polyp reproduces asexually (budding) and medusa sexually. Fertilization external. Development is indirect. Other features: Tentacles for food collection and defence. Tentacles possess cnidoblasts (stinging cells) with poison filled capsule (nematocyst). Cnidoblast is used to kill or paralyse the enemies & prey. CNIDOBLAST Polyp and Medusa are 2 kinds of body forms. Show polymorphism and alternation of generation. Habit: Free living or parasitic Digestive system: Tubular alimentary canal with mouth, pharynx, intestine and anus. Mouth may possess teeth Respiratory system: Absent Circulatory system: Absent Excretory system: H-shaped Renett cells. Ammonotelic Nervous system: Consists of circumpharyngeal ring with dorsal and ventral nerves. Reproductive system: SRP. Internal fertilization. Development is direct. Other features: Syncitial epidermis. Thick cuticle. Sexual dimorphism. Examples: Ascaris, Ancylostoma, Wuchereria, Enterobius Habit: Terrestrial, fresh water or marine or parasitic. Digestive system: Pharynx, oesophagus, stomach, intestine. Respiratory system: Cutaneus respiration. Some have branchial (gill) respiration Circulatory system: Closed type Excretory system: Nephridia. Aq. forms are ammonotelic and terr. forms ureotelic. Nervous system: A pair of cerebral ganglia (brain) and a double ventral nerve cord. Reproductive system: Earth worms and leeches are hermaphrodites. Free swimming trochophore larva. Other features: True segmentation. Covered by thick cuticle. Locomotory organs are setae or parapodia. Examples: Earthworm, Leech, Neries, Aphrodite, Chaetopterus Habit: Cosmopolitan Digestive system: Well developed. Mouth parts are different types. Respiratory system: Gills, trachea, book gills or book lungs. Circulatory system: Open type Excretory system: Either Antennary glands or Malpighian tubules or coxal glands. Aq. forms are ammonotelic. Ter. forms are uricotelic. Nervous system: A nerve ring followed by a double ventral nerve cord, which is ganglionated. Reproductive system: Sexes are separate. External fertilization in aq.forms. Internal fertilization in land forms. Oviparous. Some are viviparous. Other features: Jointed appendages. 3 regions: head, thorax and abdomen. Body is covered by cuticle. Ecdysis (moulting) present. Metamorphosis present. Examples: Spider, Scorpion, Crab, Prawn, Lepisma, insects etc. Other Features: Body is covered with spines for protection. Head absent. Endoskeleton (ossicles) present. Water vascular system for locomotion and food capture. Great power of autotomy and regeneration. Examples: Star fish, Echinus, Echinocardium, Antedon, Cucumaria Habit: Marine Digestive system: Complete Respiratory system: Gills Circulatory system: Open type Excretory system: Proboscis gland Nervous system: Reproductive system: infra-epidermal type Sexes are separate. Fertilization external. Development is indirect. Other features: Cylindrical body composed of an anterior proboscis, a collar and a long trunk. Examples: Balanoglossus, Saccoglossus These are animals with notochord, dorsal tubular nerve cord and pharyngeal gill slits. Notochord is a flexible rod located in the mid dorsal line between the alimentary canal and the nerve cord in the embryo. Chordata Non-chordata Notochord is found in the embryonic stage Absent Central nervous system is dorsal, hollow and single Ventral, solid and double Pharyngeal gill slits present Absent Ventral heart Dorsal heart (if present) A post-anal tail is present Absent Endoskeleton and exoskeleton present Only exoskeleton Hepatic portal system present Absent VERTEBRATA (Loss Cyclestemat J “4 : “ Claws Agnatha Chencrid tyes Super (Cass L “pisces Clas Gnothoestomota Onichthyes Tettogocta \" Reptilia Class Manunalia Vartebrato B Mine, ( Hag i i tbh ) == PISCES { FISHES} BEARS FINS == (Lass (Lass Chendbrich tues Catecdhth yes Dry & cornified skin, epidermal scales or scutes Snakes and lizards shed their scales as skin cast. Tympanum represents ear. Limbs- 2 pairs (if present) 3-chambered heart (but a septum partially separates ventricle). Heart is 4-chambered in crocodiles. Poikilotherms Fertilisation internal Oviparous Development is direct Examples: Chelone (Turtle), Testudo (Tortoise) Chameleon (Tree lizard), Calotes (Garden lizard) Crocodilus (Crocodile), Alligator, Gavialis (gharial) Hemidactylus (Wall lizard), Sphenodon (Tautara), Draco (flying dragon or flying lizard), Phrynosoma (horned lizard), Varanus (monitor), Poisonous snakes: Naja (Cobra), Bangarus (Krait), Vipera (Viper), Crotalus (rattle snake), Enhydrina (sea snake) etc. Non-poisonous snakes: Python, Typhlos (blind snake), Dryophis (tree snake) Presence of feathers Possess beak Forelimbs are modified into wings Hind limbs have scales and are modified for walking, swimming, or clasping tree branches Skin is dry without glands except the oil gland at the base of tail Long bones are hollow and pneumatic Digestive tract with additional chambers, the crop and gizzard Heart is 4-chambered Homoiotherms (warm-blooded). Double respiration. Air sacs connected to lungs. No urinary bladder. Fertilisation is internal. Oviparous. Development is direct. E.g. Corvus (Crow), Columba (Pigeon), Psittacula (Parrot), Struthio (Ostrich), Pavo (Peacock), Gullus (Fowl), Bubo, Aptenodytes (Penguin), Neophron (Vulture) etc. Presence of mammary glands (milk producing glands). 2 pairs of limbs for walking, running, climbing, burrowing, swimming or flying. Skin with hair. External ear (Pinnae) Heterodont, thecodont, diphyodont. 4-chambered heart. Homoiotherms. Respiration by lungs. Sexes are separate. Fertilisation internal. Viviparous (except Echidna and Platypus). Development is direct. E.g. Ornithorhynchus (Platypus), Macropus (Kangaroo), Pteropus (flying fox), Camelus (Camel), Macaca (Monkey), Rattus (Rat), Canis (dog), Felis (Cat), Elephas (Elephant), Equus (Horse), Delphinus (Common Dolphin), Balaenoptera (blue whale), Panthera tigris (Tiger), Panthera leo (lion) Protochordata (Acraniata) Vertebrata (Craniata) Urochordata (Tunicata) Cephalochordata Notochord present only in larval tail Body is covered by test made up of tunicin Exclusively marine Retrogressive metamorphosis Hermaphrodite E.g. Ascidia, Salpa, Doliolum. Notochord extends from head to tail region and is persistent throughout the life Exclusively marine Fish-like No definite coelom Sexes are separate E.g. Branchiostoma (Amphioxus or Lancelet) Possess notochord during the embryonic period Notochord is replaced by a cartilaginous or bony vertebral column in the adult Ventral muscular heart Kidneys for excretion and osmoregulation Paired appendages which may be fins or limbs Ascidia