What Is The Phylum Arthropoda And What Are Its Characteristics?

Arthropoda is a Greek word meaning JOINT FEET. It is the largest phylum with more than 80% of living animals falling into this category.

This phylum includes insects, crustaceans, arachnids etc.

The characteristics of the Phylum Arthropoda are:

1) Exoskeleton - All members of this phylum have an external skeleton made of chitin. It provides protection.

2) Metamerism - This means that the body of the Arthropods is composed of numerous segments called Somites.

3) Joint Appendages - Arthropods have joint appendages, which are modified into specialized organs for walking, eating, and grasping purposes.

4) They have a dorsal heart.

5) Ventral Nervous System - They have a ventral nerve cord with ganglia(swellings) in each segment.

6) Open Circulatory System - In Arthropods the brain is located at the the front end (most anterior). A dorsal vessel directs the blood towards the brain. Their open circulatory system allows this blood to circulate back towards the rest of the body.

7) Sexual Reproduction - Sexual reproduction or the uniting of female and male gametes is the most common mode of reproduction in Arthropods. But, there are some parthenogenic insects. Parthenogenesis means that the females produce female offspring without mating.

Phylum Athropoda:
The Phylum is called invertebrate because they are living organisms having no backbone. There are more than 1.2 million types of invertebrates on earth. Each phylum has its own characteristics.

Phylum Arthropoda's body consists of multiple joints, but only on external side. Their body is covered by strong shell made of Chitin. Their legs consist of multiple joints; that's why it has so been named. Arthro means joint and Poda means foot. These organisms are found in water, land and in air. This phylum has multiple kinds. Prawn, crab, spider, scorpion, centipede, millipede and insects are all examples of this type of phylum.

Insects form most of this type. They are three-fourth of this type. Insects consist of these joints: Head, thorax and abdomen. Their legs consist of three joints whereas feathers consist of two joints which help them in flying. In addition to these their head consists of couple of prominent antennas like housefly, butterfly and grass hopper etc.

Some arthropods' legs consist of four joints like spider, scorpion etc.
Some arthropods are long body insects and their body consists of multiple joints. One or two legs are joint with each of the joint. For example, Centipede, millipede etc.

Arthropoda means jointed legs. Phylum Arthropoda is the most populated phylum of division invertebrate. It is comprise of a vast group of animals. Most of them are insects with joined legs. They have partitions in their legs. They all have three proper pairs of legs. Their body is divided into three region; head, thorax and abdomen. Head is the upper part of body which has mandibles and other organs. Thorax is the mid body region. It is of small size than head and abdomen. Third region is that of abdomen which is flattened and spread. It is covering most part of the body.
They are covering 75% of the whole animal kingdom. They have salient features. Body is multi-cellular; it is composed of more than one cell. They are quite visible with naked eye. Some of them are poisonous. Some of them are non-poisonous. Some of them have developed respiratory system as compared to the members of other phyla. Some of them have book lungs, trachea, etc. their blood is of while colour. Respiration occurs through blood as well. They have triploblastic body wall. Hope this much information would be helpful to you. You may search in books.

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