Taxonomic categories, Hierarchy , Units of Classification
Taxonomic Categories:
The living organisms are classified but later they are divided into different categories for better understanding. The category is a part of overall taxonomic arrangement called as "Taxonomic Category". And all the components of categories together called as "Taxonomic Hierarchy".
Kingdom ,division ,class, order, family, genus ,species are the categories of organisms are arranged in the sequential manner called as" Hierarchical Sequence". All these organisms are arranged in this manner compulsory.
The Hierarchical sequence like family, order, etc. are also facultively categories like sub-orders, sub -family, etc.
Taxonomic Hierarchy:
Taxon:A taxonomic group of any rank in the system of classification is called as "Taxon". (H.J.Lam1948) e.g in plant Kingdom each one of the following such as Angiosperms, Dicotyledonae ,Polypeptalae, Malvaceae represents a taxonomic group i.e taxon.
Fig: Classification of China -rose and Cobra.
Units of Classification:
There are some units of classification from which we can easily differentiate them for better understanding they are as follows species ,genus ,family ,chort/order ,class ,division /phylum, sub-Kingdom ,Kingdom.
1) Species:
Species is the principal taxonomic unit ranking below a genus and denoted by latin binomial (considered as the basic ) unit of classification .It is a group of organisms that can interbreed under natural condition to produce fertile offspring .
Species are divisible in modern taxonomy are sub-division of species such as sub- species varieties and populations are seen and given more importance . For e.g Homo sapians.
2) Genus:
Genus is a taxonomic rank larger than Species used for classification of living and fossil organisms. Genus is a group of species bearing close resemblance to one another in their,
morphological characters but they do not interbreed( to breed together such as cross breed) for example tiger, leopard, lion all these animals belongs to same genus Panthera .
They have common characters yet are different from each other because their genus is same but species is different . Another example is genus Solanum Brinjal and potato belong to this genus.
3) Family:
Family ranks larger than genus . A family is taxonomic rank in classification of organisms between genus and order. A family represents a group of closely related genera example genera like Hibiscus, Gossypium,
Sida ,Bombax are included in same family Malvaceae .Cat also belongs to family of leopards,tigers and lions. Family felidae but dog belongs to different family Canidae.
4) Cohort/Order:
An order is a group of closely related family showing definite affinities .Order is a step above family in taxonomic hierarchy.Order is taxonomic rank used in classification of organisms and recognised by nomenclature codes.
Members belonging to the same order but different families show very few dissimilarities.e.g: Family - Papavraceae, Brassicaceae,
Capparidaceae ,etc. with parietal placentation (ovules develop on the inner wall of the ovary) - are grouped in order Parietales. Cats and dogs belongs to same order Carnivora.
5) Class:
Class is a group of different orders .it is distinct taxonomic rank of biological classification having its own distinctive name . Class has higher taxonomic rank than order
For example: Primates belong to class Mammalia . Thus,Monkeys, gorillas, gibbons, (primtes) and dogs, cats ,tigers have different orders but belongs to same class (Carnivora).
6) Division/Phylum:
The divisionis a category composed of related classes for example The divisions Angiospermae includes two classes - Dicotyledonae Angiospermae includes two classes Dicotyledonae and Monocotyledonae ( In animal classification division is a sub- unit of category / phylum).
7) sub-Kingdom:
Different divisions having some similarities form "Sub-Kingdom".
E.g: The divisions Angiospermae and Gymnospermae with the sub-Kingdom Phanerograms or Spermatophyta. 8) Kingdom: Different sub kingdom's come together and form "Kingdom". It is the highest taxonomic category.
example - sub-Kingdom Phanerogams and Cryptogams form the plant Kingdom or Plantae which includes all the plants while animals are included in Kingdom Animalia.
The Taxonomic categories have broad categories. Scientist have added sub-categories to this in order to place organisms in more scientific manner and for better understanding .As we go higher in taxonomic ranking number of common characters go on decreasing.
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| Taxonomic categories, Hierarchy , Units of Classification |
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