Wednesday, July 29, 2020

Animal Kingdom - Notes | Class 11 | Part 14: Chordata (Tetrapoda)

4. ANIMAL KINGDOM


SUPERCLASS TETRAPODA

Class Amphibia


  • They live in aquatic & terrestrial habitats and need water for breeding.

  • Body has head & trunk. Some have tail.

  • Moist skin without scales. Most have 2 pairs of limbs.

  • Tympanum represents ear.

  • 3-chambered heart (2 auricles + 1 ventricle).

  • Poikilotherms (Cold-blooded animals): Animals that lack the capacity to regulate their body temperature.

  • Alimentary canal, urinary & reproductive tracts open into a Cloaca which opens to exterior.

  • Respiration is by gills (in larva), lungs & skin

  • Sexes are separate. External fertilisation. Oviparous.

  • Development is indirect.

Examples
  • Bufo (Toad)

  • Rana (Frog)

  • Hyla (Tree frog)

  • Salamandra (Salamander)

  • Ichthyophis (Limbless amphibia)


Class Reptilia

  • Dry & cornified skin, epidermal scales or scutes.

  • Snakes and lizards shed their scales as skin cast.

  • Limbs- 2 pairs (if present).

  • Crawling mode of locomotion.

  • Tympanum represents ear.

  • 3-chambered heart (4- chambered in crocodiles).

  • Poikilotherms.

  • Well-developed alimentary canal.

  • Respiration by lungs.

  • Internal fertilisation. Oviparous.

  • Development is direct.

Examples: 
  • Chelone (Turtle)

  • Testudo (Tortoise)

  • Chameleon (Tree lizard)

  • Calotes (Garden lizard)

  • Crocodilus (Crocodile)

  • Alligator

  • Hemidactylus (Wall lizard)

  • Poisonous snakes: Naja (Cobra), Bangarus (Krait), Vipera (Viper) etc.

  • Non-poisonous snakes: Python etc.




Class Aves (Birds)

  • Presence of feathers and beak. Forelimbs are modified into wings.

  • Dry skin without glands except the oil gland at the base of tail.

  • Hind limbs have scales and are modified for walking, swimming or clasping tree branches.

  • Hollow & pneumatic long bones.

  • Tympanum represents ear.

  • 4-chambered heart.

  • Homoiotherms (warm-blooded animals): Animals having ability to maintain a constant body temperature.

  • Digestive tract has additional chambers, the crop & gizzard.

  • Double respiration.

  • Air sacs connected to lungs.

  • Internal fertilisation.

  • Oviparous.

  • Development is direct.

Examples
  • Corvus (Crow)

  • Columba (Pigeon)

  • Psittacula (Parrot)

  • Struthio (Ostrich)

  • Pavo (Peacock)

  • Aptenodytes (Penguin)

  • Neophron (Vulture) etc.



Class Mammalia

  • Presence of mammary glands (milk producing glands).

  • Skin with hair.  

  • 2 pairs of limbs for walking, running, climbing, burrowing, swimming or flying.

  • External ear (Pinnae).

  • 4-chambered heart.

  • Homoiotherms

  • Well-developed alimentary canal.

  • Dentition is Heterodont, thecodont & diphyodont.

  • Respiration by lungs.

  • Sexes are separate.

  • Internal fertilisation.

  • Viviparous (except Echidna and Platypus).

  • Development is direct.

Examples

  • 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)

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