|Clockwise from top-left: a haptophyte, some diatoms, a water mold, a cryptomonad, and Macrocystis, a phaeophyte|
The origin of the Chromalveolata was thought to be a secondary endosymbiosis between a bikont (cell with two flagella) and a red alga. This union led to plastids containing chlorophyll c. In Cavalier-Smith's classification, the Chromalveolata was one of the six major groups within the eukaryotes.
The classification has been challenged.
A potato plant infected with Phytophthora infestans.
Chromalveolate Facts for Kids. Kiddle Encyclopedia.