#SHORT NOTES NEET PREPARATION (Chapter 1) -TAXONOMIC CATEGORIES
TAXONOMIC CATEGORIES
Classification = not a single step process but involves hierarchy of steps (Each step represents a rank or category)
Category – part of overall taxonomic arrangement = taxonomic category
All categories together constitute = taxonomic hierarchy
Each category referred to unit of classification (rank is commonly known as taxon pl: taxa)
ORDER OF TAXONOMY = GROUPS – CATEGORY – RANK (EACH RANK OR TAXON – UNIT OF CLASSIFICATION)
Common Category – Kingdom, phylum or division, class, order, family, genus and species
SPECIES
Group of individual organisms with fundamental similarities = Species
Distinguish between one species from the other closely related species based on distinct morphological differences
Example: Mangifera indica, Solanum tuberosum (potato) and Panthera leo (lion). Indica, tuberosum and leo = represent specific epithets,
First words Mangifera, Solanum and Panthera = genera (represent another higher level of taxon or category)
Each genus = have one or more than one specific epithets represent different organisms (morphological similarities)
Example: Panthera has another specific epithet = tigris
Solanum includes species like nigrum and melongena
GENUS
Genus – comprises a group of related species which has more characters in common in comparison to species of other genera
Genera – aggregates of closely related species
For example, potato and brinjal = two different species but belong to the genus Solanum
Panthera leo (Lion), P.pardus (leopard) and P.tigris (tiger) – several common features (all species of the genus Panthera). This genus Panthera is differed from another genus Felis which include cats
FAMILY
The next category (Family) – has a group of related genera (with still less number of similarities as compared to genus and species)
Families = characterized on the basis of both vegetative and reproductive features of plant species
For Example, plants = three different genera Solanum, Petunia and Datura are placed in the family Solanaceae
Animals = Genus Panthera (lion, tiger, leopard) and genus Felis (cats) in the family Felidae. Features of cat and dog = have some similarities and some differences as well. They are separated into two different families (Felidae and Canidae)
ORDER
Species, genus and families = number of similar characters. Order and other higher taxonomic categories are identified based on aggregates of characters.
Order is the assemblage of families which exhibit a few similar characters; plant families like Convolvulaceae, Solanaceae = included in the order Polymoniales (based on the floral characters)
Animal order Carnivora = includes families like Felidae and Canidae
CLASS
Class = category includes related orders. For example, Class Mammalia contains order Primata (comprising monkey, gorilla and gibbon) and order Carnivora (tiger, cat and dog)
PHYLUM
Next higher category Phylum Chordata includes animals (fishes, amphibians, reptiles, birds along with mammals). All have common features (Presence of notochord and dorsal hollow neural system)
In plants, classes with a few similar characters are assigned to a higher category called Division
KINGDOM
All animals belonging to various phyla = assigned to the highest category called Kingdom (Animalia)
Kingdom Plantae comprises all plants from various divisions.
Higher from species to kingdom (number of common characteristics (decreasing), lower the taxa (more common characteristics share).
Higher the category = greater difficulty in determining relationship to other taxa at the same level
