page_title: Cavalier-Smith's system of classification
section_title: The seventh kingdom: Chromista
hierarchical_section_title: Cavalier-Smith's system of classification / Eight kingdoms model / The seventh kingdom: Chromista
context_page_description: The biological classification system of life introduced by British zoologist Thomas Cavalier-Smith involves systematic arrangements of all life forms on earth. Following and improving the classification systems introduced by Carl Linnaeus, Ernst Haeckel, Robert Whittaker, and Carl Woese, Cavalier-Smith's classification attempts to incorporate the latest developments in taxonomy. His classification has been a major foundation in modern taxonomy, particularly with revisions and reorganisations of kingdoms and phyla.
  Cavalier-Smith has published extensively on the classification of protists. One of his major contributions to biology was his proposal of a new kingdom of life: the Chromista, although the usefulness of the grouping is questionable given that it is generally agreed to be an arbitrary grouping of taxa. He also proposed that all chromista and alveolata share the same common ancestor, a claim later refuted by studies of morphological and molecular evidence by other labs. He named this new group the Chromalveolates.
context_section_description: By 1981, Cavalier-Smith had divided the all the eukaryotes into nine kingdoms. In it, he created Chromista for a separate kingdom of some protists.
  Most chromists are photosynthetic. This distinguishes them from most other protists which lack photosynthesis. In both plants and chromists photosynthesis takes place in chloroplasts. In plants, however, the chloroplasts are located in the cytosol while in chromists the chloroplasts are located in the lumen of their rough endoplasmic reticulum. This distinguishes chromists from plants.
  Based on the addition of Chromista as a kingdom, he suggested that even with his nine kingdoms of eukaryotes, "the best one for general scientific use is a system of seven kingdoms", which includes:
  Plantae,
  Animalia,
  Protozoa,
  Chromista
  Fungi,
  Eubacteria, and
  Archaebacteria.
caption: The brown algae are a member of the kingdom Chromista.
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