Definitions (Classification of Organisms)

CLASSIFICATION OF ORGANISMS

Taxonomy: The branch of science which deals with identification, nomenclature and classification of animals and plants.

Classification: The arrangement of organisms into various groups and sub groups on the basis of similar and dissimilar characteristics is called classification.

Nomenclature: The process of giving scientific name to an organism is called nomenclature.

Binomial system of nomenclature: The system of assigning two names first generic name and second specific name to an organism is called binomial system of nomenclature.

Genus: A taxonomic category ranking below a family and above a species and generally consisting of a group of species sharing similar characteristics.

Species: A group of closely related organisms which resembles one another in all essential morphological and reproductive characters and can interbreed freely and produce fertile offspring.

Taxonomic hierarchy: The arrangement of taxonomic groups in their proper order according to their taxonomic character is called taxonomic hierarchy.

Phanerogams: The plants which bear flowers and seeds are called Phanerogams.

Gymnosperms: The plants whose seeds are naked or not enclosed in fruits are called gymnosperm.

Angiosperm: Angiosperm is the well developed flowering plants whose seeds are enclosed inside fruits.

Monocotyledon: The plants which contain only one cotyledon in their seed are called monocotyledon.

Dicotyledon: The plants which contain two cotyledons in their seeds are called di-cotyledon.

Chordates: Chordates are the advanced animals which possess a notochord at some stage of their life.

Notochord: Notochord is a flexible rod-like structure running along the dorsal surface of chordate embryos ventral to the nerve cord.

Vertebrates: Vertebrates are the animals which have a backbone (vertebral column).

Warm-blooded animals: The animals whose body temperature remain constant and do not change according to the environment are called Homoeothermic or Warm-blooded animals.

Cold-blooded animals: The animal whose body temperature changes according to the surroundings is called Poikilothermic or Cold-blooded animals.

Amphibians: the cold blooded vertebrates adapted to live both on land and in water.

Reptiles: The cold blooded vertebrates which crawl on the ground.

Mammals: mammals are the most advanced vertebrates which give direct birth to their babies are called mammals.