HISTORY AND CLASSIFICATION OF BIRDS
The problems of classification of birds Has gained the attention of ornithologist and many systems have been proposed in order to establish their lineage until the beginning of the 19th century. The problem was solved in a rather over simplified way by using only significant characters especially external life forms and way of life and diet. Thus these birds whose toes are joined by welds where grouped in the natatoes. Those with long legs in the gralatories, those distinguished by their arrangement of their toes and their ability to move up and down tree trunks in the seanoords and those with hooked bills and carnivorous diet in the rapores. It is to Charles Darwin an evolutionist that we owe a new approach to systematic placing of birds in a sequence which reflects in the phylogenic and grouping them according to their actual (.......). Other notable works on modern classification of birds are peter (1931-1981) and Wetmore (1961) on grouping birds along the phylogenic hierarchy either on orders, family, genus and species. Their work have been accepted by very many ornithologist especially in America and western Europe. The characteristics used by peter and Wetmore in grouping birds into their various phylogenic groups are examined as; 1. Birds classed as vertebrates (chordate). The chordate designation means that birds belongs to a large division (phylum) of animals which includes all the form possessing the common bone. 2. BIRDS CLASSED AS AVES: these class aves encompasses the well-defined group of animals which includes all the birds and nothing except the birds. The best known animals easily observed single characteristics classes is the type of integumentary covering or outside rapping which in the case of birds are the feathers. The feathery covering is the only obvious feature not possessed by other animals. 3. Ordinary characters for birds are often based on internal features such as the characteristics of the palata and the arrangement of the bones of the (....). The general character of the bills and feet are very useful. The name of the orders in American system ends in "former". 4. FAMILY: family distinguishing Aves Includes variation in the bills, state of the tarsals and number and comparative length of the nostrils. Family name ends with "idae" for example "stnicttionidae" 5. GENUS: these are distinguished by minor variations in bills, tarsals, feet, (promaners) and to some extent the colour pattern. 6. SPECIES: species are the real structured units in the classification of birds. The main characteristics for grouping species is based on potentially interbreeding in natural populations which are reproductively isolated from other such groups. MAJOR CHARACTERISTICS USED IN CLASSIFYING BIRDS
1. BIOLOGICAL AND ANATOMICAL CHARACTERS: This class of characters has been used for long and still remains the most valuable to the systematists who understands how to eliminate the effects of the environment or the way of life especially the diets, morphological characters or the plumage provides much better indications. Some groups are distinguished by the fine characters of their feathers e.g. humming birds and birds of paradise. The distribution of the colour area like the colour pattern is equally valuable. The form of the bill has also been used as those have been used to group the horn bills. In other to supplement external characters, avian systematists have called upon internal anatomy which provides many useful indications. Some anatomical characters have been preserved unaltered during evolution and therefore show primitive characters of greatest interests, these especially of the lower parts of the skull and particularly the palates whose structural variety has held the attention of anatomist because they preserve ancestral traits of some phylogenetic validity. 2. BIOLOGICAL AND ETHOLOGICAL CHARACTERS: biology of birds also provides many...
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