Animal Kingdom II

Phylum: Arthropoda

They have the following characteristics:

1. Body is segmented and divided into three parts. They are head, thorax, and abdomen.
2. They have usually three pairs of jointed legs and two pairs of wings.
3. They have compound eyes and feelers.
4. Sexes are separate and life cycle completes in four phases i.e. egg, larva, pupa, and adult.
5. Their body is covered externally with an exoskeleton.
6. Their mouthparts are well developed for chewing, piercing and sucking.
7. They are unisexual i.e. mal;e and female sex are separate

The phylum arthopoda are divided into four classes. They are crustacean, insecta, myriapoda, and arachnida.

Class: Crustacea

1. They are aquatic animals.
2. Head and thorax are fused to form a cephalothorax.
3. Respiration takes either by gills or general body surface.
4. Head bears a pair of compound eyes and five pairs of appendages.

Examples: prawn, crab, cray-fish etc.

Class: Insecta

1. They are mostly terrestrial and rarely aquatic.
2. The body is divided into three parts: head, thorax, and abdomen.
3. Head bears a pair of compound eyes and a pair of antenna.
4. Thorax bears three parts of legs and one or two pairs of wings.

Examples: grasshopper, termite, butterfly, housefly etc.

Class: Arachnida

1. The animals of this class are terrestrial.
2. The body is divided into two parts: cephalothorax and abdomen.
3. They have four pairs of walking legs.
4. They do not have compound eyes and feelers.

Examples: spider, scorpion, mite etc.

Phylum: Mollusca

1. They have a soft body which is usually covered with a calcareous shell.
2. Body is divided into head, visceral mass, and foot.
3. The head bears mouth, tentacles, and sense organ.
4. Their body is not symmetrical.
5. They are unisexual.
6. They have well- developed organ system.
7. They are haemocoelomateanimals.

Examples: snail, slug etc.

Phylum: Echinodermata

They have the following characteristics:

1. The body of these animals is soft and unsegmented.
2. The body is covered with spine, which is made up of calcareous shell except octopus.
3. Their body maybe star-like, elongated etc.
4. They do not have a distinct head.
5. They have tube feet for locomotion and peculiar system for food gathering.
6. The mouth is situated on oral side .
7. The anus is situated on aboral side.

Examples: starfish, sea-silly etc.