 One difference that places fungi in a different kingdom is that its cell walls contain chitin, unlike the cell walls of plants, bacteria and some protists. Similar to animals, fungi are heterotrophs, that is, they acquire their food by absorbing dissolved molecules, typically by secreting digestive enzymes into their environment. Growth is their means of mobility, except for spores, which may travel through the air or water (a few of which are flagellated). Fungi are the principal decomposers in ecological systems. These and other differences place fungi in a single group of related organisms, named the Eumycota (true fungi or Eumycetes), that share a common ancestor (is a monophyletic group), an interpretation that is also strongly supported by molecular phylogenetics. This fungal group is distinct from the structurally similar myxomycetes (slime molds) and oomycetes (water molds). The discipline of biology devoted to the study of fungi is known as mycology (from the Greek μύκης, mukēs, meaning "fungus"). In the past, mycology was regarded as a branch of botany; today it is a separate kingdom in biological taxonomy. Fungi are genetically more closely related to animals than to plants.
