Classification

There are about one million different kinds of animals, ranging from the gaint Blue whale to to the microscopic protozans. The insects form the largest group. Scientists have so far indentified about seven hundred thousand diffent kinds. Mammals, the group that includes dogs, horses, cats-and Man- total around four thousand species. Other species’ totals include eleven thousand birds, five thousand reptiles, thirteen thousand species of fish, three thousand amphibians, two thousand species of centipede and eight thousand species of millipede.

Arachnids-the spiders and their allies-tot up an amazing thirty-five thousand species.

The Latin names used in classification relate either to the type of animal, or in some cases to the person who discovered, or the place where it florishes. The genus name is always printed with a capital letter and the species name with a small letter. If a proper name is used in a species, it is always Latinized, as in the name of Coke’s hartebeeste, Alcephalus cokei. Zoologists use Latin names for describing animals in order to be quite sure exactly what animals they are talking about. Names of animals differ widely from one language to another. The English bear is the Italian orso, the French ours and the German Bar. But all nations can understand clearly what is meant by the family name for bears, Ursidae.

Another reason for having an international Latin code is that the same name often describes different animals, even in the same language. For example, to the English a robin is a small songbird. An American would be referring to a larger bird of the same family, while to an Austrialian a robin is a type of flycatcher. Americans usually use buffalo for bison, while in the Old World, a buffalo is any one of several animals similar to an ox. The jack rabbit of North America is actually a hare. On the other hand, however, the American Timber wolf and the European wolf are both varities of the same animal. They differ only in size and colouring-just as members of the human race do.

In taxonomy-the science of classification-there are seven basic ranks, which to a zoologist explains exactly what kind of animal he is reading about. There are also a number of intermediate ranks.

Kingdom is the largest rank. An organism can belong to either the Plantae or the Animalia kindgom, though some scientists make a claim for a third kingdom, the Protista for organisms on the borderline, such as bacteria.

Phylum (plural phyla) is the largest sub-division of the animal kingdom, covering animals of broadly similar character. All animals with any kind of backbone are in the phylum Chordata.

Class , the main sub-division of a phylum, brings together animals with a closer relationship. The class Mammalia, for instance embraces all animals that suckle their young and have mammary glands.

Order, takes the sub-division a stage farther. The Mammalia, for example, are divided into eighteen orders, such as the Marsupialia, Primates, Rodentia and Carnivora.

Family includes animals that are recognizably similar. Among the Carnivora, or the flesh-eaters, the family Felidae contains all the cat-like animals.

Genus (plural genera) is a group of closely related animals within a family. The Felidae include the genera Panthera-the big cats such as lions, Felis-the cats that purr but don’t roar, Acinonyx-the cheetah with its non-retractible claws and Lynx – the lynx.

Species is the smallest division, and defines animals that are of the same kind and that can breed together. Lions (Panthera leo) and tigers (Panthera tigris) are two species in the genus Panthera. Occasionally different species will interbreed, such as lions and tigers in captivity, producing ligers where the father is a lion and tigons where the father is a tiger. The offspring, however, are sterile, meaning that they can’t reproduce.