What are the Characteristics of the Kingdom Animalia

What are the Characteristics of the Kingdom Animalia

Kingdom : Animalia or Animal Kingdom 

  •  These organisms are multicellular, eukaryotic and without chlorophyll.
  • The cells possess no cell walls and plastids.
  • Central vacuoles are absent but small vacuoles may occur.
  • Most of them are free moving (except sponges and some coelentrates)
  • Nutrition is primarily ingestive.
  • Reproduction is generally sexual and the haploid stage is represented only by gametes.
  • Growth of organisms stops when the adult stage is reached.

What are the Characteristics of the Kingdom Animalia 1Phylum – Porifera :

  • Sessile (stalk-less) and marine except one group that lives in fresh water.
  • Simplest multicellular, diploblastic animals.
  • Have organisation at cellular colony level. Thus, cells are loosely held together and do not form tissues.
  • Asymmetrical or radially symmetrical. Sponges may be vase-like, rounded, sac-like branched.
  • Body is perforated by numerous pores, the ostia that open into a canal system having canals and chambers lined with collared flagellated cells or choanocytes.
  • Examples – Sycon, Euplectella, (Venus flower basket) Spongilla (Fresh water sponge).

What are the Characteristics of the Kingdom Animalia 2Phylum – Cnidaria (Coelenterata) :

What are the Characteristics of the Kingdom Animalia 3

  • Aquatic, mostly marine, a few such as Hydra are fresh water solitary or colonial forms.
  • Body shows radial symmetry.
  • Possese specialized cells (cnidoblasts) bearing stinging organoids called nematocysts. Nematocysts serve the functions of paralysing the prey by injecting poison or to hold the prey.
  • Exhibit the phenomenon of polymorphism
    (Ex- Physalia).
  • Body shows two main forms, the polyps and the medusae.
  • Examples – Hydra, Obelia (sea fur) , Aurelia(jelly fish), Metridium (sea anemone).

What are the Characteristics of the Kingdom Animalia 4Phylum – Platyhelminthes :

  • Bilaterally symmetrical and dorsoventrally flattended animals.
  • Body thin, soft, leaf-like or ribbon-like.
  • Digestive cavity (when present) with a single opening, the mouth (anus is absent).
  • Suckers and hooks are usually present.
  • Circulatory and respiratory system and skeleton are absent.
  • Excretory system consists of blind tubules called protonephridia.
  • Examples : Dugesia (Planaria), Fasciola (liver fluke), Schistosoma (Blood fluke), Taenia solium (Pork Tape worm).

What are the Characteristics of the Kingdom Animalia 5Phylum – Aschelminthes or nematoda

  • They are parasitic or free-living.
  • They are triploblastic, unsegmented and show bilateral symmetry.
  • Body cavity is not a true coelom.
  • Alimentary canal is complete.
  • Sexes are separate.
  • Examples : Ascaris (Round worm), Enterobius (Pin worm), Wuchereria (filaria worm)

What are the Characteristics of the Kingdom Animalia 6Phylum – Annelida :

  • They occur in moist soil, fresh water and sea.
  • They are elongated, with segmented body and bilateral symmetry.
  • First animals with true body cavity (coelom).
  • Body bears lateral appendages for locomotion in the form of chitinous setae or parapodia.
  • Examples : Nereis (sand worm) Aphrodite (sea mouse), Pheretima (earthworm), Hirudinaria (Cattle leech)

What are the Characteristics of the Kingdom Animalia 7Phylum – Arthropoda :

  • Body is covered with a thick chitinous covering.
  • Respiration through general body surface, by gills, air tubes (tracheae) or book-lungs.
  • Body segments are grouped into two regions-cephalothorax (head and thorax together and abdomen, or three regions-head, thorax and abdomen.
  • Triploblastic, bilaterally symmetrical and metamerically segmented animals.
  • Each body segment usually bears paired lateral and jointed legs or appendages.
  • Example : Palemon (Prawn), Daphnia (water flea), Limulus (King crab), Palamnaeus (Scorpion)

What are the Characteristics of the Kingdom Animalia 7Phylum – Mollusca :

  • They have soft, unsegmented body.
  • Body is divided into three regions  (head  visceral mass and ventral foot).
  • Outer surface is covered by a hard calcareous shell.
  • Respiration is by gills called ctenidia.
  • The sexes are usually separate.
  • Examples : Chiton, Pila (Snail), Unio (Fresh water mussel), Octopus (Devil fish).

What are the Characteristics of the Kingdom Animalia 9Phylum – Echinodermata :

  • They are marine, gregarious (live in groups) and free-living animals.
  • Shape may be star-like, spherical or elongate.
  • Body surface is covered all over by calcareous spines.
  • Aristotle’s lantern for mastication.
  • Their symmetry is radial in adults but bilateral in larvae.
  • Tube feet for locomotion.
  • These are unsegmented.
  • Body cavity is modified into a water-vascular system or ambulacral system with tube like outward extension for locomotion, called tube feet.
  • Examples : Asterias (Star fish), Echinus (Sea urchin), Holothuria (Sea cucumber), Antedon (Feather star)

What are the Characteristics of the Kingdom Animalia 10Phylum – Chordata

  • Chordata are characterized by following basic features :
  • A dorsal, hollow, tubular nerve cord.
  • Notochord present.
  • Gill slits in the pharynx.
  • Tail behind the anal opening.
  • Ventral heart.

What are the Characteristics of the Kingdom Animalia 11Sub-phylum : Protochordata

  • The sub-phylum protochordata includes animals which are bilaterally symmetrical, unsegmented, tripolblastic and have a body cavity or coelom.
  • The animals belonging to protochordata possess a notochord at some stage in the life history. This is flexible rod that lies between the dorsal nerve tube and the gut.
  • The notochord provides a place for muscles to attach. It increases internal support and locomotory power.
  • Protochordates are usually marine, soft, have worm-like or vase-like forms.
  • Examples : Balanoglossus (a corn worm or tongue worm), Herdmania and Amphioxus, etc.

What are the Characteristics of the Kingdom Animalia 12Sub-phylum : Vertebrata

  • The sub-phylum vertebrata includes animals which are bilaterally symmetrical, triploblastic, coelomic and segmented.
  • The animal body typically consists of four regions : head, neck , trunk and tail.
  • The notochord is replaced partly or fully by a jointed vertebral column (back bone) in the adult. The body of vertebrates is characterized by the presence of a well developed skeletal system that allows a special distribution of muscle attachment points to be used for movement.
  • Besides vertebral column and internal skeleton the vertebrates have a well developed nervous system (brain) and sense organs (eyes, ears and nose).
  • The vertebrates have a complex differentiation of body tissues or organs.
  • There are two pairs of appendages (fins or limbs)
  • Respiration is by gills in lower aquatic vertebrates. Higher land forms have lungs for gaseous exchange.
  • Sexes are separate.

Subphylum Vertebrata is divided into seven classes :

  • Class : Pisces
  • Class : Amphibia
  • Class : Reptilia
  • Class : Aves
  • Class : Mammalia

Pisces

  • The animals belonging to class-Pisces are commonly called fishes. They exclusively live in water
  • The skin of fishes is covered with scales/plates, which helps these animals to live in water
  • The body may be long, laterally compressed and spindle shaped or dorsiventrally flattened and disc shped. It usually consists of head, trunk and a musclular tail.
  • The muscular tail and fins help them to swim in water and move from one places to another.
  • Fishes are cold-blooded animals and their hearts have only two chambers – one auricle and one ventricle.
  • Fishes obtain oxygen dissolved in water and breathe through gills.
  • They are egg laying animals. Fertilization is external.

There are many kinds of fishes. They have been broadly grouped under three categories.

  • Cyclostoma : The round mouthed fishes. Examples, The hag fish, the lamprey.
  • Chondrichthyes : The cartilaginous fishes. Examples Scoliodon (dog fish or the Indian Shark), sting ray, electric ray (Torpedo) (figure).
  • Osteichthyes : The bony fishes. Examples, Labio rohita (Rohu), Hippocampus (Sea horse), Tuna, etc.

What are the Characteristics of the Kingdom Animalia 13What are the Characteristics of the Kingdom Animalia 14 Class – Amphibia :

  • In evolutionary terms, amphibians form the first group among the chordates to live out of water and to comprise first four-legged (tetrapod) land vertebrates. They live on land but lay their eggs in water. Amphibians are vertebrates leading two lives.
  • These cold blooded animals live partly in fresh water and partly on land (moist places).
  • Skin is smooth or rough, moist, slimy, glandular and mostly without scales.
  • Heart 3 chambered.
  • Body with distinct head and trunk, no neck.
  • Two pairs of pentadactyl (five digit) limbs are present. Digits or toes without claws. Limbs may be absent in some cases.
  • Example : Ichthyophis, Amphiuma (congo ell), Salamandra, Ambystoma, Necturus, Rana (bull frog), Bufo (toad), Hyla (tree-frog).

What are the Characteristics of the Kingdom Animalia 15Class – Reptilia :

  • Cold-blooded, terrestrial or aquatic vertebrates with body covered with dry water-proof skin having horny scales or scute plates.
  • Heart 3½ chambered. Crocodyles have 4 chambered heart.
  • Body varies in form and is usually divided into head, neck, trunk and tail.
  • Limbs tetrapodous pentadacytle (five-toed) type with clawed digits (limbs are absent snakes and some lizards).
  • Tympanum small and depressed.
  • Teeth are present in all reptiles except in tortoises and turtles.
  • Example : Kachuga (roofed-terrapin), Testudo (land-tortoise), Uromastix (sand-lizard), Hemidactylus (wall lizard), Calotes (garden-lizard), Draco (flying-lizard) Chamaeleon, Cobra etc.

What are the Characteristics of the Kingdom Animalia 16Class – Aves :

  • Warm-blooded, tetrapodous vertebrates (birds) with various flight adaptations.
  • Size ranges from smallest humming bird to largest ostrich.
  • Heart 4 chambered.
  • Horny scales persist on the feet but feathers cover most of the body. Cutaneous glands are absent.
  • Boat-shaped body is divisible into head, neck, trunk and tail.
  • Fore-limbs modified into wings for flight. Kiwis have vestigial wings.
  • Example : Gallus (chicken), Passer (house sparrow), Corvus (crow), Columba (pigeon), Psittacula (parrot), Pavo (peafowl peacock), Eudynamys (koel), Bubo (owl)

What are the Characteristics of the Kingdom Animalia 17Class – Mammalia  :

  • Mammals are primarily terrestrial vertebrates. They occur in all sorts of habitats from the polar regions to the tropics.
  • The body is variously shaped and generally divisble into head, neck, trunk and tail.
  • The skin is glandular and mostly covered by a horny epidermal exoskeleton of hair.
  • There are two pairs of pentadactyl limbs. These are variously adapted for various purposes.
  • Respiration occurs only by lungs.
  • The heart is four chambered, having two auricles and two ventricles.
  • Sexs are usually distinguishable externally.
  • Mammals are mostly viviparous (alive-bearing). However, some are oviparous and lay eggs (e.g., platypus and echidna. Kangaroos give brith to very poorly developed young ones). They are characterized by having milk-secreting mammary glands in the females for sucking the young for some time after birth.
  • Examples : Macropus (Kangaroo), Bat, Ratuus (rat), Oryctolagus (rabit), Felis (cat), Panthera (lion, tiger, leopard), Canis (dog) Elephas (elephant), Balaena (whale), Macaca (monkey), Hamo (man), Pan (chimpanzee)

What are the Characteristics of the Kingdom Animalia 18