Q. Classification of plants and animals?

The first and foremost step in the classification of plants and animals is the. grouping together of individual organisms on the basis of relationships or associations among them. These groups constitute families. The family name is a plural adjective used as substantive ending-aceae for plant families and-idae for animal families :to the stem of generic name of the included generic names. For example, Rosaceae (from Rosa), Geraniaceae (from Geranium) Lamiaceae (from Lnmium).

The family name suggested on the basis fillegitimate stem name is conserved to be illegitimate unless conserved according to the recommendations of the international code. You should know that some family names are agreed to because of long usage e.g. Palmae (Arecaceae type Areca L), leguminosae (Fabaceae type faba Mll), Gramineae (Poaceae type Poa L), and Ranidae (Wanla tigrina).

The increase in the number of known species together with the degree of relationship between them facilitates the inclusion of organisms into different families. In Units 2 and 3 you have read about artificial system of classification of plants and animals. You should know that the family is said to be natural when all its members are derived from common ancestral stock i.e. of monophyletic origin. Furthermore this ' is for your information and understanding, that the families of higher plants are separated from one another by features such as inflorescence type, ovary position, placentation type, number of carpels, ovule type and the disposition of sexes as in dioecism and monoecism. A family is not of any particular size. You can include any number of organisms depending upon the similarity and the relationship between them. When a family is large and comprised of many components you can divide it into units called sub-families. These should bear Latin names terminating by the ending-oideae. For example, the family Pagaveraceae (opium family) has been .splitted into three sub-families namely Pagaveroideae, Fumaroideae and Hypecoideae. Thus you must have noticed that in all these sub-families, there is and ending or suffix-oideae.