explain taxonomic categories in class11
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It is also called Linnaean hierarchy or taxononmic hierarchy or Taxonomic classification. It was first proposed by Linaeus. Hierarchy of categories is the classification of organism in a definite sequence of categories (taxonomic categories) in a descending order starting from kingdom. The number of similar characters of categories decreases from lowest rank to highest rank. The hierarchy includes seven obligate categories – kingdom, division or phylum, class, order, family, genus and species. The categories are arranged in descending sequence keeping the kingdom at the top. In order to make taxonomic position of species more precise, certain categories have been added to this list. They are called intermediate categories.
Types of Taxonomic Categories
There are 7 main taxonomic categories. They are obligate categories i.e, they are strictly used at the time of any plant classification.
1. Species: Species (used both as singular and plural) is a natural population of individuals or group of population which resemble one another in all essential morphological and also reproductive characters so that they are able to interbreed freely and produce fertile offspring. Mango is species indica of genus mangifera (mangifera indica). Potato is species tuberosum of genus solanum (solanum tuberosum).
2. Genus: it is a group or assemblage of relate species which resemble one another in certain correlated characters. Correlated Characters are those similar or common features which are used in delimitation of a taxon above the rank of species. All the species of genus are presumed to have evolved from a common ancestor.
3. Family: it is taxonomic category which contains one or more related genera. All the genera of a family have some common features or correlated characters. They are separable from genera of a related family by important and characteristic differences in both vegetative and reproductive features. Thus the genera of cats (felis) and leopard (panther) are included in the family felidae.
4. Order: the category includes one or more related families. Thus the family solanaceae is placed in the order polemoniales along with four other related families (convolvulaceae, boraginaceae, hydrophyllaceae and polemoniaceae). Similarly, the families fekidae and canidae are included under the order carnivore alongwith hyaenidae (hyaenas) and ursidae (bears)
.5. Class: a class is made of one or more relates order. For example, the class dicotyledoneae (dicotyledonae, dictoyledons) of flowering plants contains all dicots which are grouped into several orders (e,g. Rosales, passiflorales, polemoniales, sapindales, ranales, etc.) likewise, class mammalian of animals includes all mammals which range from bats (order chiroptera),kangaroos (order marsupialia). Rodents (order rodentia), whales (order cetacean), carnivores (order cornivora) to great apes and man (order primate).
6. Division or phylum: it is a category higher than that of class. The term phylum is used for animals while division is commonly employed for plants. A division or phylum is formed of one or more classes. The phylum chordate of animals contains not class mammalian but also aves (birds), reptilian (reptiles), amphibian (amphibians), cyclostomata, chondrichthyes, osteichthyes (fishes) etc.
7. Kingdom: it is the highest taxonomic category. All plants are included in kingdom plantae while all animals belong to kingdom animalia.
There are some extra categories like sub division, sub order, sub family, tribe, sub tribe,. etc. They are not regularly used. They are used only when they are needed.
Explanation: