species:
= a group of organisms that have a unique set of characteristics (like body shape and behavior) that distinguishes them from other organisms. If they reproduce, individuals within the same species can produce fertile offspring.
= the basic unit of biological classification. Scientists refer to species using both their genus and species name. The house cat, for example, is called Felis catus.
= The lowest principal unit of biological classification formally recognized as a group of organisms distinct from other groups. In sexually producing organisms, "species" is more narrowly characterized as a group of organisms that in natural conditions freely interbreed with members of the same group but not with members of other groups
= , n: The boundaries of this taxonomic level (the most precise in the hierarchical system of binomial nomenclature ) are hotly debated among scientists and there is little real consensus about where to draw the lines between species, subspecies, morphs, races, variants, etc. In general, a species is a group of organisms that resemble one another in appearance, general behavior, ecological niche, chemical makeup and processes, and genetic structure. Organisms that reproduce sexually are classified as members of the same species only if they can actually or potentially interbreed with one another and produce fertile offspring. It should be noted that some (though quite few) taxonomists believe the species level of classification is frequently invalid and these scientists only recognize classifications down to the level of genus (again, these taxonomists represent a very small minority view).

genus:
= taxonomic group containing one or more related species
= A group in the classification of organisms. Classification level abovethe species group. It consists of similar species. Similar genera (pluralform of genus) are grouped into a family

tribe:
= a taxonomic category between a genus and a subfamily

family:
= a taxonomic group containing one or more genera;
= a division of classification including a number of genera agreeing in oneor a set of characters and so closely related that they apparently aredescended from one stem (definition by Smith).
= A major category in the taxonomic hierarchy, comprising groups of similargenera. Families are thought by some to represent the highest naturalgrouping. The Latin names of families usually end in the suffix -aceae(plants) or - idae (animals). Groups of similar families are placed inorders. Large families may be split into tribes.
= 5th rank in Taxonomic system. Kingdom, Phylum, Class, Order, Family,Genus, Species. Family names end in -aceae for plants, eg Liliaceae(lilies), and -idae for animals, eg Macropodidae (kangaroos).Biology - Flora& Fauna. Ref MM

Last modified on Friday, 20 October 2006