red algae - Fossil record, Taxonomy, Species, Red Algae as food

A large and diverse group of alga-like plants, ranging in form from single cells to large differentiated bodies; reddish colour stems from the mixture of photosynthetic pigments, chlorophyll a, phycobiliproteins, and carotenoids inside the cells; reproduction involves the production of an egg cell inside a specialized organ (oogonium) receptive to the male gamete. (Class: Rhodophyceae.)

iRed algae
Scientific classification
Kingdom: Protista Phylum: Rhodophyta Wettstein, 1922
Possible classes
Florideophyceae Bangiophyceae Cyanidiophyceae

The red algae (Rhodophyta, IPA: [ˌrəʊdə(ʊ)ˈfʌɪtə], from Greek: ῥόδον (rhodon) = rose + φυτόν (phyton) = plant, thus red plant) are a large group of mostly multicellular, marine algae, including many notable seaweeds. Other reddish algae are classified not as red algae but as Chromista which are hypothesied to have acquired their chloroplasts from red algae through endosymbiosis.

Fossil record

The oldest fossil identified as a red alga is also the oldest fossil eukaryote that belongs to a specific modern taxon.

Taxonomy

The diverse eukaryotes that constitute the red algae have been the focus of numerous recent molecular surveys and remain a rich source of undescribed and little known species for the traditional taxonomist.

Below are two valid published taxonomies of the red algae, although neither necessarily has to be used, as the taxonomy of the algae is still in a state of flux. 2006

Classification system according to Saunders and Hommersand 2004

Kingdom Plantae Haeckel Subkingdom Biliphyta Wettstein Phylum Rhodophyta Wettstein Subphylum Cyanidiophytina subphylum novus Class Cyanidiophyceae Merola et al Subphylum Rhodophytina subphylum novus Class Bangiophyceae Wettstein Class Compsopogonophyceae Saunders et Hommersand Class Florideophyceae Cronquist Class Porphyridiophyceae classis nova Class Rhodellophyceae Cavalier-Smith Class Stylonematophyceae classis nova

Kingdom Plantae Haeckel Subkingdom Rhodoplantae Phylum Cyanidiophyta Class Cyanidiophyceae Merola et al Phylum Rhodophyta Wettstein Subphylum Rhodellophytina Class Rhodellophyceae Cavalier-Smith Subphylum Metarhodophytina Class Compsopogonophyceae Saunders et Hommersand Subphylum Eurhodophytina Class Bangiophyceae Wettstein Class Florideophyceae Cronquist Subclass Hildenbrandiophycidae Subclass Nemaliophycidae Subclass Ahnfeltiophycidae Subclass Rhodymeniophycidae

Species

There are around 4,100 known species, with nearly all of them marine, and only 200 that live in freshwater. Some examples are:

Atractophora hypnoides Gelidiella calcicola Lemanea Palmaria palmata Schmitzia hiscockiana Chondrus crispus Mastocarpus stellatus

Red Algae as food

Several species are used as food.