Classification of the Animal Kingdom
Phyla. Each large group of animals, for instance, the Protozoa, Worms, Molluscs and Arthropoda, is called a phylum.
The Worms have a more complex anatomy. They are also multicelled, but have no legs. They are subdivided into three phyla Earthworms, Roundworms, Flatworms.
The phylum. Mollusca is composed of animals having a shell, mantle and foot.
The phylum Arthropoda encompasses animals having segmented legs and chitin-covered bodies.
The majority of the arthropods are not large. True, some of the beetles may grow as a big as a hens egg, and some butterflies may have a wingspread as wide as two pages of your textbook, whereas some sea crustaceans may have a body as big as a rabbit. But these species are much smaller than the vertebrates, whose growth is not hampered by their skeletons.
Arthropodas play a very important part in the life of nature and man. They belong to the largest phylum which includes, among others, over a million species of insects.
Class. The phyla are subdivided into classes.
The beetles, moths, butterflies, bugs, mosquitoes, flies, and bees belong to the Class Insecta, coming under the Phylum Arthropoda.
There are many classes the class Fishes, the class Amphibia the class Reptilia, the class Birds, the class Mammalia.
An insect is an animal whose body is made up of three parts - a head, a thorax, and an abdomen. It has three pairs of jointed limbs; breathes through a trachea; has a pair of antennae (feelers) to act as an organ of sense; and sees by means of compound eyes.
The ticks and spiders belong to the class Arachnida. They are characterized by a definite number of jointed limbs (four pairs). The compound eyes and antennae are absent. Some are totally blind, others carry simple eyes, which are very small. The body is commonly divided into a cephalothorax and an abdomen. Sometimes they are combined into one whole. Many species are very harmful to man.
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