Biological classification

Biological classification‏‎, also known as taxonomy, is the process by which biologists group and categorize organisms by biological type, such as species or genus. The biological classification system is hierarchical and includes seven major levels: Kingdom, Phylum, Class, Order, Family, Genus, and Species. This system is based on similarities and differences in organisms' physical or genetic characteristics.

History

The concept of biological classification dates back to the ancient Greeks, including Aristotle and Plato, who classified organisms based on their physical characteristics. However, the modern system of biological classification was developed by Carl Linnaeus, a Swedish botanist, in the 18th century. Linnaeus' system, known as Linnaean taxonomy, is still in use today, although it has been significantly modified and expanded.

Levels of Classification

The seven major levels of classification, from broadest to most specific, are:

• Kingdom: The highest level of classification, which groups organisms into five major categories: Animalia, Plantae, Fungi, Protista, and Monera.
• Phylum: Each kingdom is divided into multiple phyla (plural of phylum). For example, the Animalia kingdom includes the phyla Chordata (animals with backbones), Arthropoda (insects, spiders, and crustaceans), and others.
• Class: Each phylum is divided into classes. For example, the Chordata phylum includes the classes Mammalia (mammals), Aves (birds), and others.
• Order: Each class is divided into orders. For example, the Mammalia class includes the orders Carnivora (carnivores), Primates (primates), and others.
• Family: Each order is divided into families. For example, the Carnivora order includes the families Felidae (cats), Canidae (dogs), and others.
• Genus: Each family is divided into genera (plural of genus). For example, the Felidae family includes the genera Panthera (lions, tigers, leopards, and jaguars) and Felis (domestic cats and related species).
• Species: The most specific level of classification. Each genus is divided into species. For example, the Panthera genus includes the species Panthera leo (lion) and Panthera tigris (tiger).

Modern Developments

In recent years, advances in genetics and molecular biology have led to the development of a new system of classification, known as cladistics. This system classifies organisms based on their evolutionary relationships, rather than their physical characteristics.

See Also

• Binomial nomenclature
• Phylogenetics
• Systematics