Desmids are an order The Latin suffix -formes meaning "having the form of" is used for the scientific name of orders of birds and reptiles, but not for those of mammals and invertebrates (Desmidiales) of green algae The green algae are the large group of algae from which the embryophytes (higher plants) emerged. As such, they form a paraphyletic group, although the group including both green algae and embryophytes is monophyletic (and often just known as kingdom Plantae). The green algae include unicellular and colonial flagellates, usually but not always,[1] comprising around 40 genera The term comes from Latin genus "descent, family, type, gender" , cognate with Greek: γένος - genos, "race, stock, kin" and 5,000[2] to 6,000[3] species There are many definitions of what kind of unit a species is . A common definition is that of a group of organisms capable of interbreeding and producing fertile offspring, and separated from other such groups with which interbreeding does not (normally) happen. Other definitions may focus on similarity of DNA or morphology. Some species are, found mostly but not exclusively in fresh water Freshwater refers to naturally occurring water on the surface such as bogs, ponds, lakes, rivers and streams, and underground in aquifers and underground rivers. Freshwater is characterized by having low concentrations of dissolved salts. The term specifically excludes seawater and brackish water. Most are unicellular The cell is the structural and functional unit of all known living organisms. It is the smallest unit of an organism that is classified as living, and is often called the building block of life. Some organisms, such as most bacteria, are unicellular . Other organisms, such as humans, are multicellular. (Humans have an estimated 100 trillion or 1014, and are divided into two compartments separated by a narrow bridge or isthmus. Desmids assume a variety of highly symmetrical Symmetry generally conveys two primary meanings. The first is an imprecise sense of harmonious or aesthetically pleasing proportionality and balance; such that it reflects beauty or perfection. The second meaning is a precise and well-defined concept of balance or "patterned self-similarity" that can be demonstrated or proved according and generally attractive shapes, which provide the basis for their classification. Each compartment has one chloroplast Chloroplasts are organelles found in plant cells and other eukaryotic organisms that conduct photosynthesis. Chloroplasts capture light energy to conserve free energy in the form of ATP and reduce NADP to NADPH through a complex set of processes called photosynthesis, and no flagella A flagellum is a tail-like structure that projects from the cell body of certain prokaryotic and eukaryotic cells, and functions in locomotion. There are some notable differences between prokaryotic and eukaryotic flagella, such as protein composition, structure, and mechanism of propulsion. An example of a flagellated bacterium is the ulcer-. Sexual reproduction occurs through a process of conjugation,[4] also found among the Zygnematales The Zygnematales (Greek: ζυγός + νήμα (nēma) (nom.), νήματος (nēmatos) (gen.)), also called the Conjugales, are an order of green algae, comprising several thousand different species in genera such as the well-known Zygnema and Spirogyra. All the members of this group develop into unbranched filaments, one cell thick, which grow. These two groups are closely related, and may be united as the division Gamophyta. The desmids are sometimes treated as members of the Zygnematales, but more often given the separate order Desmidiales.
References
- ^ Gontcharov AA, Marin BA, Melkonian MA (January 2003). "Molecular phylogeny of conjugating green algae (Zygnemophyceae, Streptophyta) inferred from SSU rDNA sequence comparisons". J. Mol. Evol. 56 (1): 89–104. doi The Digital Object Identifier System is a managed system for persistent identification of content-related entities on digital networks. These entities may be content items (digital files, physical objects, abstract works), or any related entities in a content transaction (e.g. licenses, parties, etc.). "DOI" is sometimes used to mean the:10.1007/s00239-002-2383-4. PMID 12569426. http://dx.doi.org/10.1007/s00239-002-2383-4.
- ^ Van den Hoek, C., D. G. Mann, & H. M. Jahns, 1995. Algae:An Introduction to Phycology, page 468. (Cambridge: Cambridge University Press). ISBN 0-521-30419-9
- ^ Brook, Alan J., 1981. The Biology of Desmids, page 1. (Berkeley: University of California Press). ISBN 0-520-04281-6
- ^ Kapraun DF (April 2007). "Nuclear DNA content estimates in green algal lineages: chlorophyta and streptophyta". Ann. Bot. 99 (4): 677–701. doi The Digital Object Identifier System is a managed system for persistent identification of content-related entities on digital networks. These entities may be content items (digital files, physical objects, abstract works), or any related entities in a content transaction (e.g. licenses, parties, etc.). "DOI" is sometimes used to mean the:10.1093/aob/mcl294. PMID 17272304. http://aob.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=17272304.
External links
| Classification of Archaeplastida The Archaeplastida are a major line of eukaryotes, comprising the land plants, green and red algae, and a small group called the glaucophytes. All of these organisms have plastids surrounded by two membranes, suggesting they developed directly from endosymbiotic cyanobacteria. In all other groups, plastids are surrounded by three or four membranes, / Plantae sensu lato Plants are living organisms belonging to the kingdom Plantae. They include familiar organisms such as trees, herbs, bushes, grasses, vines, ferns, mosses, and green algae. About 350,000 species of plants, defined as seed plants, bryophytes, ferns and fern allies, are estimated to exist currently. As of 2004, some 287,655 species had been |
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| Rhodophyta The red algae (or Rhodophyta, pronounced /roʊˈdɒfɨtə, ˌroʊdəˈfaɪtə/, from Greek: ῥόδον = rose + φυτόν (phyton) = plant, thus red plant) are one of the oldest groups of eukaryotic algae, and also one of the largest, with about 5,000–6,000 species of mostly multicellular, marine algae, including many notable seaweeds. Other |
Rhodophyceae · Bangiophyceae Bangiophyceae was a class of red algae; it has since been merged with the Floridophyceae to form the Rhodophyceae. The Bangiophyceae, as defined traditionally, are paraphyletic.. Their taxonomic identification has been difficult because of a lack of distinct morphological features, and the presumed morphological plasticity of the species · Florideophyceae Florideophyceae was a class of red algae. It is now merged with the Bangiaceae into the Rhodophyceae. They were once thought to be the only algae to bear pit connections, but these have since been found in the filamentous stage of the Bangiacae · Goniotrichales · Stylonematophyceae
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| Glaucocystophyceae The glaucophytes, also known as glaucocystophytes or glaucocystids, are a small group of freshwater microscopic algae. Together with the red algae and Viridiplantae they form the Archaeplastida. However, the relationships between the red algae, green algae and glaucophytes are unclear, in large part due to limited study of the glaucophytes |
Glaucocystis · Cyanophora · Gloeochaete
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| Viridiplantae In some classification systems they have been treated as a kingdom, under various names, e.g. Viridiplantae, Chlorobionta, or simply Plantae/
Plantae
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Chlorophyta Chlorophyta, a division of green algae, includes about 7000 species of mostly aquatic photosynthetic eukaryotic organisms. Like the land plants , green algae contain chlorophylls a and b, and store food as starch in their plastids. They are related to the Charophyta and Embryophyta (land plants), together making up the Viridiplantae/GA The green algae are the large group of algae from which the embryophytes (higher plants) emerged. As such, they form a paraphyletic group, although the group including both green algae and embryophytes is monophyletic (and often just known as kingdom Plantae). The green algae include unicellular and colonial flagellates, usually but not always
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Bryopsidophyceae In taxonomy, the Bryopsidophyceae are a class of green algae, in the division Chlorophyta · Chlorophyceae The Chlorophyceae are one of the classes of green algae, distinguished mainly on the basis of ultrastructural morphology. For example the chlorophycean CW clade, and chlorophycean DO clade, are defined by the arrangement of their flagella. Members of the CW clade have flagella that are displaced in a "clockwise" direction eg · Pedinophyceae In taxonomy, the Pedinomonadaceae are a family of algae. They are small single-celled algae. Each cell has a single flagellum. It has been proposed to be either in the Mamiellales or the Ulvophyceae, but it has not been studied enough to confidently place it · Pleurastrophyceae In taxonomy, the Pleurastrophyceae are a class of green algae, in the division Chlorophyta. It was created by Mattox and Stewart in 1984, containing four genera. More recent classifications tend to split the group. On the one hand, Tetraselmis seems to be a sister to the so-called UTC clade , thus making it part of the (paraphyletic) · Prasinophyceae In taxonomy, Prasinophytes are a class of the Division Chlorophyta. These are primitive eukaryotic, marine green algae. Its best known genus is Ostreococcus , which is considered to be the smallest (ca. 0.95 μm) free-living eukaryote and which has been detected in marine samples around the world. Prasinophytes are thought to have low cellular · Trebouxiophyceae In taxonomy, the Trebouxiophyceae are a class of green algae, in the division Chlorophyta · Ulvophyceae The Ulvophyceae or Ulvophytes are class of green algae, distinguished mainly on the basis of ultrastructural morphology. The sea lettuce, Ulva, belongs here. Other well-known members include Ulothrix and Acetabularia. The Ulvophytes are diverse in their morphology and their habitat. Most are seaweeds such as those listed above. Others, such as
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Streptophyta Streptophytina is formally a subdivision or subphylum which contains two classes: Charophyceae, containing the Charales order (Charophytes sensu stricto); and Embryophyceae, which contains the embryophytes (land plants, bryophytes, and vascular plants)
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Charophyta The Charophyta are a division of green algae, including the closest relatives of the embryophyte plants. In some groups, such as conjugating green algae, flagellate cells do not occur. The latter group does engage in sexual reproduction, and motility does not involve flagella, since they are totally lacking. Flagellate cells in the form of sperm/GA The green algae are the large group of algae from which the embryophytes (higher plants) emerged. As such, they form a paraphyletic group, although the group including both green algae and embryophytes is monophyletic (and often just known as kingdom Plantae). The green algae include unicellular and colonial flagellates, usually but not always
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Embryophyta The embryophytes are the most familiar group of plants. They include trees, flowers, ferns, mosses, and various other green land plants. All are complex multicellular eukaryotes with specialized reproductive organs. With very few exceptions, embryophytes obtain their energy through photosynthesis ; and they synthesize their food from carbon/
Plantae
sensu strictissimo
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Bryophytes Bryophytes are all embryophytes that are non-vascular: they have tissues and enclosed reproductive systems, but they lack vascular tissue that circulates liquids. They neither have flowers nor produce seeds, reproducing via spores. The term bryophyte comes from Greek βρύον - bryon, "tree-moss, oyster-green" + φυτόν - fyton &
(non-vascular Non-vascular plants is a general term for those plants without a vascular system . Although non-vascular plants lack these particular tissues, a number of non-vascular plants possess tissues specialized for internal transport of water)
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Marchantiophyta The Marchantiophyta [mɑːˌkæntiˈɑːfɪtə] (help·info) are a division of bryophyte plants commonly referred to as hepatics or liverworts. Like other bryophytes, they have a gametophyte-dominant life cycle, in which cells of the plant carry only a single set of genetic information · Anthocerotophyta Hornworts are a group of bryophytes, or non-vascular plants, comprising the division Anthocerotophyta. The common name refers to the elongated horn-like structure, which is the sporophyte. The flattened, green plant body of a hornwort is the gametophyte plant · Bryophyta "Moss" Mosses are small, soft plants that are typically 1–10 cm tall, though some species are much larger. They commonly grow close together in clumps or mats in damp or shady locations. They do not have flowers or seeds, and their simple leaves cover the thin wiry stems. At certain times mosses produce spore capsules which may appear as beak-like · Horneophytopsida Horneophytopsida is a class of early vascular plants including the genera Caia, Tortilicaulis, and Horneophyton. Although formerly classified among the Rhyniophyta, the group is distinctive for having branched sporangia, and lacking true xylem
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Tracheophyta Vascular plants are those plants that have lignified tissues for conducting water, minerals, and photosynthetic products through the plant. Vascular plants include the ferns, clubmosses, flowering plants, conifers and other gymnosperms. Scientific names for the group include Tracheophyta and Tracheobionta, but neither name is very widely used.[
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Lycopodiophyta The Division Lycopodiophyta is a tracheophyte subdivision of the Kingdom Plantae. It is the oldest extant (living) vascular plant division at around 420 million years old,[citation needed] and includes some of the most "primitive" extant species. These species reproduce by shedding spores and have macroscopic alternation of generations,
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Isoetopsida The Isoetopsida is a class of the Lycopodiophyta. All living plants belong to the genus Isoetes in the order Isoetales. The order Isoetales is sometimes placed in the class Isoetopsida, sometimes in the Selaginellopsida or Lycopsida. There are about 140-150 species, with a cosmopolitan distribution but often scarce to rare. Some botanists split (Isoetales Isoëtes, also written Isoetes and commonly known as the Quillworts, is the genus of plants in the class Isoetopsida and order Isoetales. The order Isoetales is sometimes placed in the class Isoetopsida, sometimes in the Selaginellopsida or Lycopsida. They are considered "fern allies". There are about 140-150 species, with a cosmopolitan, Selaginellales Selaginella is a genus of plants in the family Selaginellaceae, which includes Spikemoss. Many workers still place the Selaginellales in the class Lycopsida . This group of plants is included in what, for convenience, is called "fern allies". S. moellendorffii is an important model organism, and its genome was sequenced by the United) · Lycopodiopsida Lycopodiopsida is a class of plants often loosely grouped as the fern allies, and includes the clubmosses. Lycopodiopsida traditionally included all the clubmosses, including Selaginella and Isoetes. However, subdivisions within the Division Lycopodiophyta are now considered ancient enough to warrant higher-level separation in accordance with (Lycopodiales)
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Euphyllophyta
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Moniliformopses (Equisetopsida, Filicopsida, Psilotopsida)
Spermatophyta: Gymnosperm (Pinophyta, Cycadophyta, Ginkgophyta, Gnetophyta) · Magnoliophyta
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see also list of plant orders
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Categories: Green algae | Plant orders
