The 'Chromista' are a paraphyletic
eukaryotic supergroup, which may be treated as a separate
kingdom or included among the
Protista. They include all
algae whose
chloroplasts contain
chlorophylls ''a'' and ''c'', as well as various colorless forms that are closely related to them. These are surrounded by four membranes, and are believed to have been acquired from some
red alga. There are three different groups:
★
Heterokonts or stramenopiles -
brown algae,
diatoms,
water moulds, etc.
★
Haptophytes
★
Cryptomonads
The name Chromista was introduced by
Cavalier-Smith in 1981; the earlier names chromophyte and chromobiont correspond to roughly the same group. Molecular trees have had some difficulty resolving relationships between the different groups. It now appears that all three share a common ancestor with the
alveolates (see
chromalveolates), but it is possible that the Chromista themselves are
paraphyletic.
References
★
Eukaryote kingdoms: seven or nine?, T. Cavalier-Smith, , , Biosystems, 1981
External links
★
UCMP: Introduction to the Chromista