In biology, all organisms are divided into categories based on their similarities. This method of categorization is called a taxonomic system. In the currently used system, the Linnaean taxonomic system, the broadest category for organisms is the level "kingdom," which has five divisions. Two of these are the kingdoms Fungi and Monera, which have many differences but share some similarities.
The kingdom Fungi includes all forms of fungus. There are many different types, including familiar species such as mushrooms and molds. There are hundreds of thousands of species and, though most are terrestrial, many live in both saltwater and freshwater as well. Fungi are nonmotile, having no method of voluntary movement. They typically live on a substrate that they use for food by excreting digestive enzymes and absorbing the nutrients from the substrate. Most acquire nutrients from decaying materials, although some are parasitic.
Members of the kingdom Monera are single-celled organisms, though they can form large colonies under favorable conditions. There is a great variety among these organisms, but they exhibit a few defining traits. These organisms do not have organelles in their cells, and their cells contain no nucleus or chromosomes. Instead, they have a loop of DNA. Their primary method of reproduction is asexual, although there are several methods of achieving genetic variation. They acquire nutrients and energy either through absorption or by photosynthesis.
While members of the kingdom Fungi can be microscopic, they are multicellular, whereas monera are always unicellular. Fungi cannot make their own energy, whereas some species of Monera are photosynthetic. Fungi also have no method of locomotion, whereas some species of Monera have the ability to move on their own. A major difference between the two are organelles, the specific divisions within a cell. Members of monera are the only organisms that lack organelles; fungi have developed organelles within their cells.
Members of the kingdoms Monera and Fungi have few similarities. One of these similarities is the fact that both acquire nutrients via absorption. Both can also form colonies, although a monera colony and a fungi colony are very different. In addition, lichens comprise a symbiotic relationship between fungi and algae. The algae can either be green algae, which is a member of the kingdom Protista, or cyanobacteria or blue-green algae, which is a member of the kingdom Monera. Lichens containing both types at once are common.