Biology · Ch 1 — The Living World
Kingdom
Kingdom
Kingdom is the highest taxonomic category. All the animals belonging to the various phyla are gathered into a single highest category — the Kingdom Animalia. In the same way, the Kingdom Plantae stands apart and includes all plants drawn from the various divisions. These two great groups are commonly referred to as the animal kingdom and the plant kingdom.
When the taxonomic categories are arranged from species up to kingdom, they form an ascending order (species being lowest and kingdom highest). These are the broad categories, but taxonomists have also created sub-categories within the hierarchy so that different taxa can be placed more soundly and scientifically.
Basis of the arrangement
The key to the hierarchy is the number of shared characteristics:
- As we move up from species towards kingdom, the number of common characteristics decreases.
- The lower the taxon, the more characters its members share.
- The higher the category, the greater the difficulty of working out its relationship to other taxa at the same level, and so the problem of classification becomes more complex.
Where some common organisms belong
The categories from genus up to phylum or division for a few familiar organisms are shown below.
| Common name | Biological name | Genus | Family | Order | Class | Phylum / Division |
|---|---|---|---|---|---|---|
| Man | Homo sapiens | Homo | Hominidae | Primata | Mammalia | Chordata |
| Housefly | Musca domestica | Musca | Muscidae | Diptera | Insecta | Arthropoda |
Drawn by us to help you understand the concept clearly, and verified to make sure it's accurate. For exams, practice from your textbook's own diagram.
This figure lays out the seven-rung ladder of taxonomic ranks that every organism is placed within, running from the narrowest, most specific group at the bottom to the broadest, most inclusive group at the top. Reading upward, the ranks are Species, Genus, Family, Order, Class, Phylum (called Division in plants), and Kingdom, with each rank joined to the one directly above it by an upward-pointing arrow.
The upward direction of the arrows marks the ascending order of the hierarchy: species is the lowest and most tightly defined rank, and kingdom is the highest and most inclusive. Climbing the ladder, each rank gathers together several of the groups sitting below it, so the members within a rank share fewer characteristics the higher you go, while the size of the group and the difficulty of working out its relationships both grow. …