Scientific classification is the act of classifying organisms into biological "groups". It is based on taxonomy, which is the science of naming, defining, and classifying groups of biological organisms by considering their shared characteristics. Organisms are grouped into taxa (or taxon, singular), and these groups are then assigned a taxonomic rank. Each group of taxa can be classified into another, larger group of higher rank, thus forming the taxonomic hierarchy.
The famed Carl Linnaeus, a Swedish botanist, is regarded as the founder of current taxonomy. He developed a system known as Linnaean taxonomy for categorizing organisms, and introduced binomial nomenclature for naming organisms.
The major ranks in modern taxonomy are:
For example, this is how humans are classified by taxonomic hierarchy:
Species: Homo sapiens