Green algae - wikipedia Green algae Green algae Stigeoclonium, a chlorophyte green alga genus Scientific classification Kingdom : Plantae Included groups Chlorophyta Charophyta Excluded groups Embryophyta ( cladistically included but traditionally excluded ) The green algae ( singular : green alga ) are a large, informal grouping of algae consisting of the Chlorophyte and Charophyte algae, which are now placed in separate divisions. The land plants, or embryophytes, are thought to have emerged from the charophytes. Therefore, cladistically, embryophytes belong to green algae as well. However, because the embryophytes are traditionally classified as neither algae nor green algae, green algae are a paraphyletic group. Since the realization that the embryophytes emerged from within the green algae, some authors are starting to include them. The clade that includes both green algae and embryophytes is monophyletic and is referred to as the clade Viridiplantae and as the kingdom Plantae. The green algae include unicellular and colonial flagellates, most with two flagella per cell, as well as various colonial, coccoid and filamentous forms, and macroscopic, multicellular seaweeds. In the Charales, the closest relatives of higher plants, full cellular differentiation of tissues occurs. There are about 8,000 species of green algae. Many species live most of their lives as single cells, while other species form coenobia ( colonies ), long filaments, or highly differentiated macroscopic seaweeds. A few other organisms rely on green algae to conduct photosynthesis for them. The chloroplasts in euglenids and chlorarachniophytes were acquired from ingested green algae, and in the latter retain a nucleomorph ( vestigial nucleus ). Green algae are also found symbiotically in the ciliate Paramecium, and in Hydra viridissima and in flatworms. Some species of green algae, particularly of genera Trebouxia of the class Trebouxiophyceae and Trentepohlia ( class Ulvophyceae ), can be found in symbiotic associations with fungi to form lichens. In general the fungal species that partner in lichens can not live on their own, while the algal species is often found living in nature without the fungus. Trentepohlia is a filamentous green alga that can live independently on humid soil, rocks or tree bark or form the photosymbiont in lichens of the family Graphidaceae. Contents 1 Cellular structure 2 Origins 3 Evolution and classification 4 Reproduction 4.1 Sex pheromone 5 Physiology 6 References 7 External links Cellular structure Green algae have chloroplasts that contain chlorophyll a and b, giving them a bright green color, as well as the accessory pigments beta carotene and xanthophylls, in stacked thylakoids. The cell walls of green algae usually contain cellulose, and they store carbohydrate in the form of starch. All green algae have mitochondria with flat cristae. When present, paired flagella are used to move the cell. They are anchored by a cross-shaped system of microtubules and fibrous strands. Flagella are only present in the motile male gametes of charophytes bryophytes, pteridophytes, cycads and Ginkgo, but are absent from the gametes of Pinophyta and flowering plants. Members of the class Chlorophyceae undergo closed mitosis in the most common form of cell division among the green algae, which occurs via a phycoplast. By contrast, charophyte green algae and land plants ( embryophytes ) undergo open mitosis without centrioles. Instead, a ' raft ' of microtubules, the phragmoplast, is formed from the mitotic spindle and cell division involves the use of this phragmoplast in the production of a cell plate. Origins Photosynthetic eukaryotes originated following a primary endosymbiotic event, where a heterotrophic eukaryotic cell engulfed a photosynthetic cyanobacterium - like prokaryote that became stably integrated and eventually evolved into a membrane - bound organelle : the plastid. This primary endosymbiosis event gave rise to three autotrophic clades with primary plastids : the green plants, the red algae and the glaucophytes. Evolution and Classification A growth of the green seaweed Enteromorpha on rock substratum at the ocean shore. Some green seaweeds, such as Enteromorpha and Ulva, are quick to utilize inorganic nutrients from land runoff, and thus can be indicators of nutrient pollution. Green algae are often classified with their embryophyte descendants in the green plant clade Viridiplantae ( or Chlorobionta ). Viridiplantae, together with red algae and glaucophyte algae, form the supergroup Primoplantae, also known as Archaeplastida or Plantae sensu lato. The ancesterial green algae was a unicellular flagellate. The Viridiplantae diverged into two clades. The Chlorophyta include the early diverging prasinophyte lineages and the core Chlorophyta, which contain the majority of described species of green algae. The Streptophyta include charophytes and land plants. Below is a consensus reconstruction of green algal relationships, mainly based on molecular data. Viridiplantae = green algae ( incl. Embryophyta ) Chlorophyta core Chlorophyta Chlorophytina Ulvophyceae Chlorophyceae Trebouxiophyceae Chlorodendrophyceae Pedinophyceae Prasinophytes Clade VIIA Prasinophytes Clade VIIC Pycnococcaceae Nephroselmidophyceae Mamiellophyceae Pyramimonadales Palmophyllophyceae Palmophyllales Prasinococcales Streptophyta = Charophyta ( incl. Embryophyta ) Mesostigmatophyceae Chlorokybophyceae Klebsormidiophyceae Phragmoplastophyta Charophyceae Zygnematophyceae Embryophyta ( land plants ) Coleochaetophyceae The algae of this paraphyletic group `` Charophyta '' were previously included in Chlorophyta, so green algae and Chlorophyta in this definition were synonyms. As the green algae clades get further resolved, the embryophytes, which are a deep charophyte branch, are included in `` algae '', `` green algae '' and `` Charophytes '', or these terms are replaced by cladistic terminology such as Archaeplastida, Plantae, Viridiplantae or streptophytes, respectively. Reproduction Green algae conjugating Green algae are eukaryotic organisms that follow a reproduction cycle called alternation of generations. Reproduction varies from fusion of identical cells ( isogamy ) to fertilization of a large non-motile cell by a smaller motile one ( oogamy ). However, these traits show some variation, most notably among the basal green algae called prasinophytes. Haploid algal cells ( containing only one copy of their DNA ) can fuse with other haploid cells to form diploid zygotes. When filamentous algae do this, they form bridges between cells, and leave empty cell walls behind that can be easily distinguished under the light microscope. This process is called conjugation and occurs for example in Spirogyra. The species of Ulva are reproductively isomorphic, the diploid vegetative phase is the site of meiosis and releases haploid zoospores, which germinate and grow producing a haploid phase alternating with the vegetative phase. Sex pheromone Sex pheromone production is likely a common feature of green algae, although only studied in detail in a few model organisms. Volvox is a genus of chlorophytes. Different species form spherical colonies of up to 50,000 cells. One well - studied species, Volvox carteri ( 2,000 -- 6,000 cells ) occupies temporary pools of water that tend to dry out in the heat of late summer. As their environment dries out, asexual V. carteri quickly die. However, they are able to escape death by switching, shortly before drying is complete, to the sexual phase of their life cycle that leads to production of dormant desiccation - resistant zygotes. Sexual development is initiated by a glycoprotein pheromone ( Hallmann et al., 1998 ). This pheromone is one of the most potent known biological effector molecules. It can trigger sexual development at concentrations as low as 10 M. Kirk and Kirk showed that sex - inducing pheromone production can be triggered experimentally in somatic cells by heat shock. Thus heat shock may be a condition that ordinarily triggers sex - inducing pheromone in nature. The Closterium peracerosum - strigosum - littorale ( C. psl ) complex is a unicellular, isogamous charophycean alga group that is the closest unicellular relative to land plants. Heterothallic strains of different mating type can conjugate to form zygospores. Sex pheromones termed protoplast - release inducing proteins ( glycopolypeptides ) produced by mating - type ( - ) and mating - type ( + ) cells facilitate this process. Physiology. The green algae, including the characean algae, have served as model experimental organisms to understand the mechanisms of the ionic and water permeability of membranes, osmoregulation, turgor regulation, salt tolerance, cytoplasmic streaming, and the generation of action potentials. References ^ Jump up to : Jeffrey D. Palmer, Douglas E. Soltis and Mark W. Chase ( 2004 ). `` The plant tree of life : an overview and some points of view ''. American Journal of Botany. 91 ( 10 ) : 1437 -- 1445. PMID 21652302. doi : 10.3732 / ajb. 91.10. 1437. Jump up ^ Delwiche, Charles F. ; Timme, Ruth E. `` Plants ''. Current Biology. 21 ( 11 ) : R417 -- R422. doi : 10.1016 / j. cub. 2011.04. 021. Jump up ^ Guiry, M.D. ( 2012 ). `` How many species of algae are there ? ''. Journal of Phycology. 48 : 1057 -- 1063. PMID 27011267. doi : 10.1111 / j. 1529 - 8817.2012. 01222. x. Jump up ^ Burrows 1991. Seaweeds of the British Isles. Volume 2 Natural History Museum, London. ISBN 0 - 565 - 00981 - 8 Jump up ^ Hoek, C. van den, Mann, D.G. and Jahns, H.M. 1995. Algae An introduction to phycology. Cambridge University Press, Cambridge. ISBN 0 - 521 - 30419 - 9 Jump up ^ Judd, W.S., Campbell, C.S., Kellogg, E.A., Stevens, P.F. and Donoghue, M.J. Sinauer ( 2002 ) Plant systematics, a phylogenetic approach. Associates Inc., Sunderland Mass. ISBN 0 - 87893 - 403 - 0, p156 Jump up ^ Bhattacharya, D ; Medlin, L ( 1998 ). `` Algal phylogeny and the origin of land plants ''. Plant Physiology. 116 : 9 -- 15. doi : 10.1104 / pp. 116.1. 9. Jump up ^ Pickett - Heaps, J. ( 1976 ). `` Cell division in eucaryotic algae ''. BioScience. 26 ( 7 ) : 445 -- 450. doi : 10.2307 / 1297481. Jump up ^ P.H. Raven, R.F. Evert, S.E. Eichhorn ( 2005 ) : Biology of Plants, 7th Edition, W.H. Freeman and Company Publishers, New York, ISBN 0 - 7167 - 1007 - 2 Jump up ^ Keeling, PJ ( 2010 ). `` The endosymbiotic origin, diversification and fate of plastids ''. Philosophical Transactions of the Royal Society B : Biological Sciences. 365 ( 1541 ) : 729 -- 748. ISSN 0962 - 8436. PMC 2817223. PMID 20124341. doi : 10.1098 / rstb. 2009.0103. Jump up ^ De Clerck, O ; Bogaert, KA ; Leliaert, F ( 2012 ). `` Diversity and Evolution of Algae ''. Advances in Botanical Research. 64 : 55 -- 86. ISSN 0065 - 2296. doi : 10.1016 / B978 - 0 - 12 - 391499 - 6.00002 - 5. Jump up ^ `` Phylogeny and molecular evolution of the green algae ''. Frederik Leliaert. 2013 - 05 - 29. Retrieved 2017 - 09 - 09. Jump up ^ Lewis, L. A & R.M. McCourt ( 2004 ). `` Green algae and the origin of land plants ''. American Journal of Botany. 91 ( 10 ) : 1535 -- 1556. PMID 21652308. doi : 10.3732 / ajb. 91.10. 1535. Jump up ^ Leliaert, Frederik ; Smith, David R. ; Moreau, Hervé ; Herron, Matthew D. ; Verbruggen, Heroen ; Delwiche, Charles F. ; De Clerck, Olivier ( 2012 ). `` Phylogeny and Molecular Evolution of the Green Algae '' ( PDF ). Critical Reviews in Plant Sciences. 31 : 1 -- 46. doi : 10.1080 / 07352689.2011. 615705. Jump up ^ Marin, Birger ( 2012 ). `` Nested in the Chlorellales or Independent Class ? Phylogeny and Classification of the Pedinophyceae ( Viridiplantae ) Revealed by Molecular Phylogenetic Analyses of Complete Nuclear and Plastid - encoded rRNA Operons ''. Protist. 163 : 778 -- 805. PMID 22192529. doi : 10.1016 / j. protis. 2011.11. 004. Jump up ^ Laurin - Lemay, Simon ; Brinkmann, Henner ; Philippe, Hervé ( 2012 ). `` Origin of land plants revisited in the light of sequence contamination and missing data ''. Current Biology. 22 : R593 -- R594. PMID 22877776. doi : 10.1016 / j. cub. 2012.06. 013. Jump up ^ `` BMC Evolutionary Biology 2014, 14 : 23 ''. Jump up ^ Leliaert, Frederik ; Tronholm, Ana ; Lemieux, Claude ; Turmel, Monique ; DePriest, Michael S. ; Bhattacharya, Debashish ; Karol, Kenneth G. ; Fredericq, Suzanne ; Zechman, Frederick W. ( 2016 - 05 - 09 ). `` Chloroplast phylogenomic analyses reveal the deepest - branching lineage of the Chlorophyta, Palmophyllophyceae class. nov. ''. Scientific Reports. 6 : 25367. ISSN 2045 - 2322. PMC 4860620. PMID 27157793. doi : 10.1038 / srep25367. Jump up ^ Lecointre, Guillaume ; Guyader, Hervé Le ( 2006 ). The Tree of Life : A Phylogenetic Classification. Harvard University Press. ISBN 9780674021839. Jump up ^ Cook, Martha E. ; Graham, Linda E. ( 2017 ). Archibald, John M. ; Simpson, Alastair G.B. ; Slamovits, Claudio H., eds. Handbook of the Protists. Springer International Publishing. pp. 185 -- 204. ISBN 9783319281476. doi : 10.1007 / 978 - 3 - 319 - 28149 - 0_36. Jump up ^ ( 1 ) ^ Jump up to : Hallmann A, Godl K, Wenzl S, Sumper M ( 1998 ). `` The highly efficient sex - inducing pheromone system of Volvox ''. Trends Microbiol. 6 ( 5 ) : 185 -- 9. PMID 9614342. doi : 10.1016 / s0966 - 842x ( 98 ) 01234 - 7. Jump up ^ Kirk DL, Kirk MM ( 1986 ). `` Heat shock elicits production of sexual inducer in Volvox ''. Science. 231 ( 4733 ) : 51 -- 4. PMID 3941891. doi : 10.1126 / science. 3941891. Jump up ^ Sekimoto H, Satoh S, Fujii T ( 1990 ). `` Biochemical and physiological properties of a protein inducing protoplast release during conjugation in the Closterium peracerosum - strigosum - littorale complex ''. Planta. 182 ( 3 ) : 348 -- 54. PMID 24197184. doi : 10.1007 / BF02411384. 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External links Green algae and cyanobacteria in lichens Green algae ( UC Berkeley ) Monterey Bay green algae Classification of Archaeplastida / Plantae sensu lato Domain Archaea Bacteria Eukaryota ( Supergroup Plant Hacrobia Heterokont Alveolata Rhizaria Excavata Amoebozoa Opisthokonta Animal Fungi ) Rhodophyta ( red algae ) Cyanidiophyceae Porphyridiophyceae Compsopogonophyceae Stylonematophyceae Rhodellophyceae Bangiophyceae Florideophyceae Glaucocystophyta ( glaucophytes ) Glaucocystophyceae Glaucocystis Cyanophora Gloeochaete Viridiplantae ( green algae & land plants ) Chlorophyta Palmophyllales Nephroselmidophyceae Prasinophyceae Pseudoscourfieldiales Pyramimonadophyceae Scourfieldiales Pedinophyceae Chlorodendrophyceae UTC clade Ulvophyceae Trebouxiophyceae Chlorophyceae Streptophyta ( charophytes, & land plants ) Mesostigmatophyceae Chlorokybophyceae Klebsormidiophyceae Phragmo - plastophyta Charophyceae Coleochaetophyceae Zygnematophyceae Embryophyta ( land plants ) Bryophytes ( non-vascular ) Marchantiophyta Anthocerotophyta Bryophyta `` Moss '' † Horneophytopsida Tracheophyta ( vascular ) Lycopodiophyta ( microphylls ) † Zosterophyllopsida † Sawdoniales Isoetopsida Lycopodiopsida Euphyllophyta ( megaphylls ) Moniliformopses ( ferns ) † Cladoxylopsida † Stauropteridales † Zygopteridales Equisetopsida Psilotopsida Marattiopsida Filicopsida Spermatophyta ( seed plants ) † Seed ferns Gymnosperms Gnetopsida Pinopsida Cycadopsida Ginkgoopsida Angiosperms or flowering plants Amborellales Nymphaeales Austrobaileyales Magnoliids Monocots Eudicots Other † Trimerophytopsida † Progymnosperm Other † Rhyniopsida † = extinct. See also the list of plant orders. Retrieved from `` https://en.wikipedia.org/w/index.php?title=Green_algae&oldid=806669229 '' Categories : Green algae Non-vascular plants Talk Contents About Wikipedia Azərbaycanca Български Català Čeština Deutsch Eesti Español Esperanto فارسی Français Gaeilge Gaelg Galego 한국어 हिन्दी Hrvatski Bahasa Indonesia Kurdî Magyar Македонски 日本 語 Nordfriisk Português Română Simple English Slovenčina Slovenščina Српски / srpski Srpskohrvatski / српскохрватски Suomi Svenska Tagalog ไทย Türkçe Українська Tiếng Việt 中文 Edit links This page was last edited on 23 October 2017, at 13 : 17. Text is available under the Creative Commons Attribution - ShareAlike License ; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia ® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization. About Wikipedia

Question: green algae is an example of which type of reproduction
Answer: alternation of generations; alternation of generations.; alternation of generations; alternation of generations