Kingdom Animalia

Kingdom Animalia

General charcteristicss

  • Eukaryotic and multicellualar
  • They have no cell walls
  • All are heterotrophic
  • Most reproduce sexually and few asexually.
  • Most show locomotion

It comprises nine phyla but only two will be discussed here; Arthropoda and Chordata

Phylum Arthropoda

  • They have jointed appendages hence the name anthropoda
  • The body is coverd with hardened exoskeleton made of chitin
  • It undergoes moulting that means shedding to allow growth in size
  • They are segmented
  • Body divided into Head, thorax and abdomen and others celaphalothorax.
  • Bilaterally symmetrical.
  • They have open circulatory system where blood flows in open cavities, the haemocoel.
  • Gaseous exchange is through tracheal system which opens through the spiracles to outside.
  • Reproduction is mainly sexual with internal fertilization. The sexes are separate.

This phylum is divided into five classes

Class Crustacea

Examples are Daphnia, crayfish, crab and prawn

Daphnia Crayfish
daphnia.jpg crayfish.jpg

Crab prawn

crab.jpg prawn.jpg

General characteristics

  • The head and thorax are fused to from cephalothorax
  • They have two pairs of antennae
  • They have between five and twenty pairs of limbs which are modified for different functions
  • Have a pair of compound eyes
  • Three pairs of mouths parts
  • Gaseous exchange is through pills
Class Chilopoda

Comprises of centipedes
centipede.jpg centipede 1.jpg

General characteristics

  • Their body is dorsa-ventrally flattened
  • The body is divided into two body parts: the head and the trunk
  • Has 15 or more segments
  • Each segment has a pair of walking legs
  • The head has a pair of simple eyes.
  • Head has a pair of antennae
  • Have poison claws on the head with secrete poison substance
  • Gaseous exchange occurs through tracheal system.
  • The sexes are separate.

Class Diplopoda

This class comprises the millipedes

millipede 2.jpg millipede 1.jpg

General characteristics

  • They have cylindrical body
  • Have three body parts
  • The body has between 9-100 segments
  • Each segment has apair of walking legs
  • The head has a pair of short antennae and mandibles.
  • They have two clumps of many simple eyes.
  • Each body segment has a pair of spiracles for breathing.
  • They have no poision claws

Class Diplopoda

This class comprise of Millipedes

General characteristics

  • They have cylindrical body
  • They have three body parts
  • Body has between 9-100 segments.
  • Each segment has two pairs of walking legs
  • The head has short pairs of antennae and mandibles
  • They have two clumps of many simple eyes.
  • Each body segment has a pair of spiracles for breathing
  • They have no poison claws.
Class Arachnida

This class includes spiders, scorpions, ticks and mites.
Spider Scorpion Tick
spider 1.jpg scopion.jpgtick.jpg


General characteristics

  • The body part has two parts; Cephalothorax and abdomen.
  • The cephalothorax consist iof fused head and thorax.
  • Theventral side of cephalothorax has two chelicerae each having a claw-like structure, which produces poison that paralyses pray.
  • The cephalothorax has four pairs of walking legs each having seven joints.
  • Each legs end in two toothed claws.
  • They do not have antennae
  • Archnids have ling books mostly for gaseous exchange.
  • Fused head has eight simple eyes.

Class Insecta

Insects form half of the population of the animals on earth. They occupy all habitats that include air, water and land in all climatic regions of the earth.

General characteristics

  • Body is divided into three body parts
  • The thorax is made up of three segments with three pairs of legs. Some insects have one or two pairs of wings.
  • The head has one pair of antennae
  • They have two compound eyes and several simple eyes
  • The mouth parts consist of mandibles, maxillae and labium that are modified according to their feeding habits.
  • The abdomen is made up of eleven of fewer segments with terminal parts modified for reproduction.
  • They breathe through spiracles; gaseous exchange is through tracheal system.
  • They undergo complete or incomplete metamorphosis.
  • Excreation is through malphigian tubules, which remove uric acid.

NB: Entomology is the study dealing with insects.

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


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