Supergroup SAR consist of Stramenopiles Alveolates and Rhizaria Previously Alveolates and Stramenopiles were grouped together as Supergroup Chromalveolata while Rhizaria belonged to a separate sugroup of that name SAR members are very diverse some have cell walls all made of cellulose while others do not Some are algae some are saprobes and others are protozoa Clade Stramenopiles This clade is currently considered to be monophyletic and consists of photosynthesizers and heterotrophs many of which have had a great impact on our biosphere Most contain two flagella one of which is coated with hair like structures Four sub groups are diatoms Phylum Bacillariophyta golden algae Phylum Chrysophyta brown algae Phylum Phaeophyta and oomycetes Phylum Oomycota a Diatoms make up a large percent of aquatic primary producers phytoplankton and fix 1 of atmospheric CO2 They are among the most important photosynthetic organisms on Earth however they store their reserves as oil not starch Diatoms are unicellular or colonial and secrete a two part silicate shell that overlaps almost like a petri dish with a cover During reproduction the two sides separate and each generate the complementary side to create a new organism Because of the strength of their silicate walls diatoms are used in production of filters and in polishing agent They are also used in forensic science as a diatom test to establish locations of incidents such as drowning as the kinds and numbers of diatoms tend to be fingerprints of particular aquatic environs Veterinarians often use diatomaceous earth skeletal remains of these organisms as an oral treatment for intestinal parasites Obtain a prepared slide of diatoms and observe the great variety of shapes Draw representatives including centric pennate and colonial diatoms Mixed Diatoms b Oomycetes also known as water molds were once considered fungi because of their filamentous structures These water molds although many are terrestrial are parasites of fish and plants Some species are saprobes that feed off dead decaying matter Well