Kingdom Animalia

Phylum Chordata

They include fishes,amphibians, reptiles, birds and mammals.

General characteristics

  • They have notochord in their developmentanl stages at their dorsal aside
  • They are bilaterally symmetrical
  • They have visceral clefts
  • The heart is ventrally located
  • They have closed circulatory system
  • They have internal skeleton.
  • They posses post anal tail although rudimentary in some.
  • They have segmented muscle blocks known as myotomes on either side if the body.

The main classes of phylum chordate are Pusces, Amphibia, Aves and Mammalia

Class Pisces

These are fishes. A number of fishes have Skelton mad u cartilage and others made up of bone. They include catfish, Nile perch, lungfish, rayfish and dogfish.

General characteristics

  • They have gills for gaseous exchange.
  • Movement is by means of gills
  • Their bodies are covered with scales.
  • Have streamlined body.
  • They don’t posses middle or external ear.
  • Their heart consists of two main chambers , the auricle and ventricle with single circulatory system.
  • Body temperature changes according to the temperature of the environment.
  • Eyes covered with nictating membrane.
  • They poses a lateral line system for sensitivity.
Class Amphibia

These include newts, salamanders, frogs and toads. They are partly aquatic and partly terrestrial.

toad.jpg frog.jpg


newt.jpg salamander.jpg

General characteristics

  • They have fur well developed limbs.
  • They have double circulatory system; their blood passes through the heart twice in a complete circuit through the body.
  • They have a three-chambered heart with two atria and only one ventricle.
  • They breed in water and fertilization is external.
  • Gaseous exchange is through the skin, lungs and gills.
  • They have two eyes and eardrum behind the eyes.
  • They are ectothermic

Class Reptilia

Reptiles are more adapted to terrestrial life then amphibians. They include turtles and tortoises, crocodiles, lizards and chameleons.
tortoise.jpg chameleon.jpg


crocodile.jpg lizard.jpg

turtle.jpg

General characteristics

  • The body is covered with dry scaly skin which reduces desicaton.
  • Some have no limbs like snakes, others have four limbs eg crocodiles
  • Fertilization is internal.
  • They lay eggs.
  • They have double circulatory system.
  • They have well developed lungs for gaseous exchange, eliminating the need to use skin or the mouth for gaseous exchange.
  • They are ectothermic

Class Aves

They comprise of birds.

Common birds include chicken, weavebird, hawks, eagles and turkeys. They are terrestrial and arboreal while some are adapted to aquatic life.

General characteristics

  • Their bodies are covered with feathers.
  • They have beaks
  • They have hollow bones
  • The sternum is enlarged to form a keel for attachment of flight muscles.
  • The hind legs are for walking or swimming.
  • The hind legs have scaly skin
  • They have double circulation with four-chambered heart.
  • They have lungs for gaseous exchange and air sacks which store air.
  • They are endothermic
  • Fertilization is internal.
  • They have internal auditory meatus

Class Mammalia

These animals inhabit various habitats.

General characteristics

  • They have mammary glands.
  • Their body is usually covered with fur or skin.
  • Their teeth are differentiated into four different types
  • They have two pinnae (external ear)
  • They usually have sweat glands.
  • They have lungs for gaseous exchange.
  • They have double circulatory exchange
  • They have four limbs
  • Have diaphragm that separate the body cavity into thoracic and abdominal cavity.
  • Their brain is highly developed
  • Have seven cervical bones at their neck.
  • They are endothermic