Brown algae room algal species characterized by being multicellular and also having brown or greenish brown color. The color is as result of the predominance of brown pigments, e.g. Fucoxanthin, in addition to the green pigments (chlorophyll a and c). Numerous of them space macroscopic. In fact, kelps are big brown seaweeds that grow in shallow oceans and type the so-called kelp forest. Fucus is another macroscopic brown algal species. They flourish in intertidal area of rocky seashores. They room harvested, dried, and processed because that the commercial production of soap, glass, etc. Castle are also used together fertilizers. Synonyms: Phaeophyta; Phaeophyceae; Fucophyceae.

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Classification

The old scheme of group entails five significant kingdoms. Among them is the kingdom Protista (protists). This group is consisted of of 3 groups: the animal-like protozoa, the plant-like algae, and the fungus-like slime molds and water molds. Algae room further split into the number of phyla: Euglenophyta, Chrysophyta (diatoms), Pyrrophyta (dinoflagellates), Chlorophyta (green algae), Phaeophyta, and also Rhodophyta.(1) current studies and also findings, though, might eventuate to transforms in the taxonomic positions and also to newer systems of classification.(2) because that instance, the phylum Phaeophyta is currently obsolete. It offered to it is in the phylum consisting of organisms commonly referred to as brown algae. At present, the brown birds are currently members that Phaeophyceae, which is just one of the taxonomic classes under the brand-new phylum, Ochrophyta.(3) Phaeophyceae is consisted of of algal species characterized by your brown or greenish-brown shade due to the visibility of brown pigments, such as fucoxanthin. However, apart from this class, various other phyla encompass some algal species that room brownish in color as well. They are phyla Dinoflagellata (dinoflagellates) and also Bacillariophyta (diatoms). However, members of Phaeophyceae are an ext popularly referred to jointly as the brown algae. In contrast to the two phyla who members room single-celled, Phaeophyceae consists of algal varieties that are multicellular.


Sub-groups

Phaophyceae is comprised of the adhering to taxonomic orders(4):

Ascoseirales Asterocladales Chordales Desmarestiales Dictyotales Discosporangiales Ectocarpales Fucales Ishigeales Laminariales Nemodermatales Onslowiales Phaeophyceae ordo incertae sedis Phaeosiphoniellales Ralfsiales Scytothamnales Sphacelariales Sporochnales Stschapoviales Syringodermatales Tilopteridales

General characteristics


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Kelp is a brown algal types that creates the so-called kelp forest. A kelp forest provides marine species a habitat. The huge kelp is regarded as the longest algal species. It might reach over 50 meter long.

Phaeophyceae is a clade consisted of of olive green to brown multicellular algae. The size could selection from a small tuft of few centimeters to the large kelp of over 50 meter long. Macrocystis pyrifera (giant kelp) is considered as the largest algae. Your characteristic greenish-brown color is deadline to and depends ~ above the quantity of fucoxanthin. Except this pigment, chlorophyll a and also c2 are likewise present. Your carbohydrate to make reservation is laminarin (β1-3 glucose polymer). Similar to various other algal groups, brown algae manifests alternation of generations. The sporophyte is regularly the more visible form. Many of the brown algae (except for the Fucales) blee sexually by sporic meiosis. Those the are capable of asexual reproduction reproduce by means of motile zoospores. The human body (thallus) the Phaeophyceae lack vascular tissues as watched in tracheophytes. Thus, brown algae perform not have true roots, stems, and leaves. The root-like structure of the brown algae is referred to as the holdfast. Similar to a true root, the holdfast serves as an anchor, preventing the algal thallus come be swept away through the current. However, the holdfast is not the major organ for water uptake as the true source is. The stem-like component of the algal thallus is called a stipe. In highly-differentiated brown birds such as Fucus, the stipe is comprised of three layers: the outer epidermis, the middle cortex, and the inner central pith. The pith may encompass a core of phloem-like cells. In other species, the pith may be hollow and gas-filled, and therefore connected with algal buoyancy. The leaf-like structure is referred to as a blade (when that is solitary and not divided), a frond (when divided), or a lamina (when flattened). The waiting bladders in the thallus are referred to as pneumatocysts. They boost algal buoyancy. Brown birds are mainly marine and also macroscopic. They fluorish especially in cold s waters.


Evolution and phylogeny

Brown algae are presumed come have developed from a symbiotic relationship between a basal eukaryote and also another eukaryote based upon having four-membraned chloroplasts. Genetically, castle are an ext closely concerned the yellow-green algae.

Biological importance

These biology are necessary as food and as habitat for many aquatic animals. Kelps produce a kelp woodland that serves as a habitat for little marine animals. Sargassum, another brown algal species, gives a floating mat as one more habitat for varied species. Ascophyllum nodosum is qualified of fixing carbon. Brown algae have alginate in your cell walls. That is extract for usage as a food thickener. Fucus species, for instance, is harvested for usage in soap and glass making. Lock are likewise used as fertilizers come crops. Other species are edible to humans.


See also

Seaweed

References

Pascher, A. (1914). “Über Flagellaten und Algen “. Berichte der deutsche botanischen Gesellschaft 32: 136–160. The NCBI taxonomy database. Retrieved native http://www.ncbi.nlm.nih.gov/taxonomy.
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