Over the last 3.7 billion years or so, living organisms on the Earth have diversified and adapted to almost every environment imaginable. The diversity of life is truly amazing, but all living organisms do share certain similarities. All living organisms can replicate, and the replicator molecule is DNA. As well, all living organisms contain some means of converting the information stored in DNA into products used to build cellular machinery from fats, proteins, and carbohydrates.In order to study the enormous diversity of organisms they need to be organised into manageable groups. This grouping of organisms is known as classification and the study of biological classification is called taxonomy. The usual method of classifying organisms, although not the only one in existence, follows the system originally proposed by the Swedish naturalist Carl Linnaeus (1707-1778) who gave each organism a two-part scientific name - a genus name and the species name (e.g. Homo sapiens). It is a hierarchical system of groupings based on evolutionary relationships. The sequence in the hierarchy is as follows: Kingdom-Phylum-Class-Order-Family-Genus-Species. |