a and b , generally giving them a bright green color. Embryophyte cells also generally ... of the term embryophyte the fertilized egg develops into a protected embryo, rather than dispersing ... and began the evolution of the embryophyte land plants. ref name BeckerMarin2009 Citation last Becker ... more details
Automatic taxobox display parents 3 Aarabia was a genus of Silurian Silu Devonian Embryophyte land plant with branching axes. ref doi 10.1666 0094 8373 2008 034 0179 HGWCTI 2.0.CO 2 References reflist Category Devonian life Category Prehistoric plants paleo stub plant stub ... more details
Orphan date February 2011 Speciesbox species cuneata fossil range fossil range Pragian Emsian ref ref name Wang2002 cite doi 10.1016 S0034 6667 02 00089 1 ref display parents 3 authority Wang, 2002 Guangnania was a genus of Devonian Early Devonian Embryophyte land plant with branching axes. ref name Boyce2008 cite doi 10.1666 0094 8373 2008 034 0179 HGWCTI 2.0.CO 2 ref It is thought to be related to the zosterophylls. ref name Wang2002 References reflist Category Devonian life Category Prehistoric plants paleo stub plant stub ... more details
Orphan date February 2009 The Glossophytes are a clade of embryophyte land plant s comprising the glossopterid s and their descendants. This includes the Gnetales and angiosperm s, as well as Bennettitales . ref name Doyle1996 cite journal author Doyle, J.A. year 1996 title Seed Plant Phylogeny and the Relationships of Gnetales journal International Journal of Plant Sciences volume 157 issue 6 pages 3 39 url http links.jstor.org sici?sici 1058 5893 199611 157 3A6 3CS3 3ASPPATR 3E2.0.CO 3B2 23 accessdate 2008 02 01 doi 10.1086 297401 ref Their monophyly is rather well supported by molecular methods, although their internal relationships are somewhat more shaky. ref name Doyle1996 The clade had diverged by the Permian , when glossopterids appear in the fossil record. ref name Doyle1996 References reflist plant stub Category Plant taxonomy ... more details
File Gametophyte2.png thumb Several gametophytes growing in a terrarium . Image Physcomitrella Protonema.jpg thumb Protonema of the moss Physcomitrella patens A gametophyte is the haploid , multicellular phase of plant s and algae that undergo alternation of generations , with each of its cells containing only a single set of chromosomes . The gametophyte produces male or female gamete s or both , by a process of cell division called mitosis . Sexual reproduction of plants The fusion of male and female gametes produces a diploid zygote , which develops by repeated mitotic cell divisions into a multicellular sporophyte . Because the sporophyte is the product of the fusion of two haploid gametes , its cells are diploid , containing two sets of chromosomes. The mature sporophyte produces spore s by a process called meiosis , sometimes referred to as reduction division because the chromosome pairs are separated once again to form single sets. The spores are therefore once again haploid and develop into a haploid gametophyte. In moss es, Marchantiophyta liverworts and Anthocerotophyta hornworts bryophytes , the gametophyte is the commonly known phase of the plant. An early developmental stage in the gametophyte of mosses immediately following germination of the meiospore is called the protonema . The adult gametophyte of mosses is called the gametophore as it carries the gamete producing sex organs. ref Ralf Reski 1998 Development, genetics and molecular biology of mosses. In Botanica Acta 111, pp 1 15. ref In most other embryophyte land plants , the gametophyte is very small. In fern s the gametophyte is a free living organism called the prothallus , in contrast to angiosperms. ref C.Michael Hogan. 2010. http www.eoearth.org article Fern Fern . Encyclopedia of Earth. National council for Science and the Environment . Washington, DC ref In gymnosperm s and angiosperm s, the gametophyte are reduced to only a few cells in angiosperms the female gametophyte embryo sac is kn ... more details
Taxobox image Ephedra chilensis 1.JPG name Streptophytina regnum Plantae unranked classis Streptophytina subdivision ranks Classes Charophyceae br Embryophyceae Streptophytina is formally a subdivision botany subdivision or subphylum but sometimes used at the division level, where more appropriate would be the use of the term Streptophyta, see below which contains two classes Charophyceae , containing the Charales order Charophyte s sensu stricto and Embryophyceae , which contains the embryophyte s land plants , bryophytes , and vascular plants . The term streptophyta , formally a term for a division botany division or phylum, is also used to indicate a subkingdom and used to include land plants embryophytes as well as several orders of green algae class Charophyceae previously included in the division Charophyta . ref http tolweb.org Green plants 2382 Green plants Bot generated title ref One study included Mesostigmatales , Chlorokybales , Klebsormidiales , Zygnematales , Coleochaetales and Charales in Streptophyta. ref name pmid16236178 cite journal author Turmel M, Otis C, Lemieux C title The complete chloroplast DNA sequences of the charophycean green algae Staurastrum and Zygnema reveal that the chloroplast genome underwent extensive changes during the evolution of the Zygnematales journal BMC Biol. volume 3 issue pages 22 year 2005 pmid 16236178 pmc 1277820 doi 10.1186 1741 7007 3 22 url http www.biomedcentral.com 1741 7007 3 22 ref References reflist Bremer, K. 1985 Summary of green plant phylogeny and classification. Cladistics 1 369 385. Lewis, L.A, McCourt, R.M. 2004 Green algae and the origin of land plants. http www.amjbot.org cgi content abstract 91 10 1535 AMERICAN JOURNAL OF BOTANY 91 10 1535 1556 OCT. Image Chara sp reproductive structure.JPG thumb reproductive structure of Chara External links http www.amjbot.org cgi content full 91 10 1437 The plant tree of life an overview and some points of view http www.sciencemag.org cgi reprint 294 5550 2351.p ... more details
Paraphyletic group image Chara sp reproductive structure.JPG domain Eukaryota unranked regnum Archaeplastida regnum Plantae divisio Charophyta included Mesostigmatophyceae br Klebsormidiophyceae br Zygnematophyceae Zygnematales Desmidiales br Charophyceae Coleochaetales Charales The Charophyta are a division of green algae , ref cite journal last Lewis first Louise A. coauthors Richard M. McCourt year 2004 title Green algae and the origin of land plants journal American Journal of Botany volume 91 issue 10 pages 1535 1556 url http www.amjbot.org cgi content abstract 91 10 1535 doi 10.3732 ajb.91.10.1535 format abstract ref including the closest relatives of the embryophyte plants. ref name pmid11743201 cite journal author Karol KG, McCourt RM, Cimino MT, Delwiche CF title The closest living relatives of land plants journal Science journal volume 294 issue 5550 pages 2351 3 year 2001 month December pmid 11743201 doi 10.1126 science.1065156 url http www.sciencemag.org cgi pmidlookup?view long&pmid 11743201 ref 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 are found in stoneworts Charales and Coleochaetales . Classification Because they exclude the embryophytes, the Charophyta make a paraphyletic group ref http tolweb.org Green plants 2382 ref although the division Charophyta is occasionally restricted to simply the Charales or stoneworts, which are monophyletic . Citation needed date September 2009 The Charophyta plus the embryophytes make up the Streptophyta , which is a monophyletic group. Distribution List of species. Chara aspera Deth. ex Wild. var. aspera Ireland Counties Down, Antrim and Londonderry. ref Morton, O. in Hackney, P. ed. 1992. Stewart & Corry s Flora of the North east of Ireland. Third edition . ISBN 0 853898 446 9 HB ref References reflist See also Strept ... more details
classified with their embryophyte descendants in the green plant clade Viridiplantae or Chlorobionta ... 1 Zygnematales and Desmidiales 2 clade 1 Coleochaetales 2 clade 1 Charales 2 Embryophyte s higher ... more details
The Plant DNA C values Database is a comprehensive catalogue of C value cell nucleus nuclear DNA content, or in diploid s, genome size data for Embryophyte land plants and algae . The database was created by Michael D. Bennett Prof. Michael D. Bennett and Dr. Ilia J. Leitch of the Royal Botanic Gardens, Kew , United Kingdom UK . The database was originally launched as the Angiosperm DNA C values Database in April 1997, essentially as an online version of collected data lists that had been published by Prof. Bennett and colleagues since the 1970s. Release 1.0 of the more inclusive Plant DNA C values Database was launched in 2001, with subsequent releases 2.0 in January 2003 and 3.0 in December 2004. In addition to the angiosperm dataset made available in 1997, the database has been expanded taxonomy taxonomically several times and now includes data from pteridophytes since 2000 , gymnosperms since 2001 , bryophytes since 2001 , and algae since 2004 see http www.rbgkew.org.uk cval updates.html 1 for update history . Note that each of these subset databases is cited individually as they may contain different sets of authors . As of September 2005, the database as a whole contains data for over 4,800 species of plants in these various taxa . A similar Animal Genome Size Database was created in 2001 by T. Ryan Gregory Dr. T. Ryan Gregory of the University of Guelph , Canada . References Bennett, M.D. and J.B. Smith. 1976. Nuclear DNA amounts in angiosperms. http www.pubs.royalsoc.ac.uk philtransb.shtml Philosophical Transactions of the Royal Society of London B 274 227 274. Bennett, M.D. and J.B. Smith. 1991. Nuclear DNA amounts in angiosperms. http www.pubs.royalsoc.ac.uk philtransb.shtml Philosophical Transactions of the Royal Society of London B 334 309 345. Bennett, M.D. and I.J. Leitch. 1995. Nuclear DNA amounts in angiosperms. http aob.oxfordjournals.org Annals of Botany 76 113 176. Bennett, M.D. and I.J. Leitch. 1997. Nuclear DNA amounts in angiosperms 583 new est ... more details
Other uses Image Gray3.png right thumb A human ovum with Corona radiata embryology corona radiata surrounding it An ovum plural ova , from the Latin language Latin word wikt en ovum Latin ovum meaning egg biology egg or egg biology egg cell is a haploid female reproductive cell or gamete . Both animal s and embryophyte s have ova. The term ovule is used for the young ovum of an animal, as well as the plant structure that carries the female gametophyte and egg cell and develops into a seed after fertilization . In Non vascular plant lower plants and algae , the ovum is also often called oosphere . Ova production In higher animals, ova are produced by female gonad s sexual glands called ovary ovaries and all of them are present at birth in mammal s, and mature via oogenesis . Human and mammal ova Image Sperm egg.jpg right thumb A sperm cell fusing with an ovum Image Acrosome reaction diagram en.svg thumb The process of fertilizing an ovum Top to bottom In the viviparous animals which include human s and all other Eutheria placental mammal s , the ovum is fertilized inside the female body, and the embryo then develops inside the uterus , receiving nutrition directly from the mother. The human ova grow from primitive germ cells that are embedded in the substance of the ovaries. Each of them divides repeatedly to give rise to several smaller cells, the oogonia . The oogonia then develop into the ova, the primary oocytes . ref cite web url http www.theodora.com anatomy the ovum.html title The Ovum in Gray s Anatomy work accessdate 2010 02 16 . ref The ovum is one of the largest biological cell cells in the human body, typically visible to the naked eye without the aid of a microscope or other magnification device. The human ovum measures 120 Micrometre m in diameter. ref http books.google.ca books?id ca51dWOR8nIC&pg RA5 PA8 IA2&dq ovum 120 micrometers&hl en&ei sXtjTI6 D4OC8gbZ6rCeCQ&sa X&oi book result&ct result&resnum 1&ved 0CDAQ6AEwAA v onepage&q 120 20micrometers ... more details
Automatic taxobox oldest fossil Early Permian authority Stotler & Stotl. Crand. display children 1 synonyms Treubiopsida Haplomitriopsida is a newly recognized Class biology class of Marchantiophyta liverworts comprising fifteen species in three genus genera . Recent cladistics cladistic analyses of cell nucleus nuclear , mitochondria l, and plastid gene sequences place this monophyly monophyletic group as the basal sister group to all other liverworts. ref name Heinrichs 2005 cite journal last Heinrichs first Jochen coauthors S. Robbert Gradstein, Rosemary Wilson, & Harald Schneider year 2005 title Towards a natural classification of liverworts Marchantiophyta based on the chloroplast gene rbcL journal Cryptogamie Bryologie volume 26 issue 2 pages 131 150 ref ref name He Nygr n 2006 cite journal last He Nygr n first Xiaolan coauthors Aino Jusl n, Inkeri Ahonen, David Glenny, & Sinikka Piippo year 2006 title Illuminating the evolutionary history of liverworts Marchantiophyta towards a natural classification journal Cladistics volume 22 issue 1 pages 1 31 doi 10.1111 j.1096 0031.2006.00089.x ref ref name Forrest 2006 cite journal last Forrest first Laura L. coauthors Christine E. Davis, David G. Long, Barbara J. Crandall Stotler, Alexandra Clark & Michelle L. Hollingsworth year 2006 title Unraveling the evolutionary history of the liverworts Marchantiophyta multiple taxa, genomes and analyses journal The Bryologist volume 109 issue 3 pages 303 334 doi 10.1639 0007 2745 2006 109 303 UTEHOT 2.0.CO 2 ref ref name Renzaglia 2007 cite journal last Renzaglia first Karen S. coauthors Scott Schuette, R. Joel Duff, Roberto Ligrone, A. Jonathan Shaw, Brent D. Mishler, & Jeffrey G. Duckett year 2007 title Bryophyte phylogeny Advancing the molecular and morphological frontiers journal The Bryologist volume 110 issue 2 pages 179 213 doi 10.1639 0007 2745 2007 110 179 BPATMA 2.0.CO 2 ref The group thus provides a unique insight into the early evolution of liverworts in particular ... more details
automatic taxobox taxon Rhynia fossil range Early Devonian image Rhynia reconstruction.jpg image caption Reconstruction of Rhynia gwynne vaughanii , redrawn after ref name kenrick P. Kenrick, P.R. Crane 1997 The origin and early diversification of land plants. A cladistic study. Smithsonian Institution Press, Washington & London, ISBN 1 56098 729 4. Fig. 4.8, p. 101. ref image width 150px display parents 4 authority Kidston & Lang 1917 subdivision ranks Species subdivision species list R. gwynne vaughanii Kidston & Lang 1917 Rhynia gwynne vaughanii was the sporophyte ref name edwards1980 Edwards, DS 1980 Evidence for the sporophytic status of the Lower Devonian plant Rhynia gwynne vaughanii Kidston and Lang. Review of Palaeobotany and Palynology, 29, 177 188 ref generation of a vascular, axial, free sporing Alternation of generations diplohaplontic embryophyte embryophytic land plant of the Lower Devonian that had plant anatomy anatomical features more advanced than those of the bryophyte s, and was basal to modern vascular plants or tracheophyte eutracheophyte s. Description R. gwynne vaughanii was first described as a new species by Kidston and Lang in 1917. ref name Kidston1917 R. Kidston and W.H. Lang 1917 On Old Red Sandstone plants showing structure from the Rhynie chert bed, Aberdeenshire. Part I. Rhynia gwynne vaughanii , Kidston and Lang. Transactions of the Royal Society of Edinburgh, 5, 761 784. ref The species is known only from the Rhynie chert in Aberdeenshire , Scotland , where it grew in the vicinity of a silica rich hot spring . Rhynia was a vascular plant, and grew in association with other vascular plants such as Asteroxylon Asteroxylon mackei , a probable ancestor of modern clubmoss es Lycopsida , and with pre vascular plants such as Aglaophyton major , which is interpreted as basal to true vascular plants. ref name Edwards1986 D.S. Edwards 1986 Aglaophyton major , a non vascular land plant from the Devonian Rhynie chert. Botanical Journal of the ... more details
Taxobox name Seed Plants image Welwitchia.jpg image width 200px image caption Welwitschia mirabilis a member of the Gnetophyta fossil range Devonian ? or earlier to recent regnum Plant ae subdivision ranks Divisions subdivision Pinophyta Cycad ophyta Ginkgo phyta Gnetophyta Flowering plant Magnoliophyta Bennettitales extinction The spermatophytes from the Greek word also known as phanerogams comprise those plant s that produce seed s. They are a subset of the embryophyte s or land plants. The living spermatophytes form five groups cycad s, a subtropical and tropical group of plants with a large crown of compound leaves and a stout trunk, Ginkgo , a single living species of tree , conifers , cone bearing trees and shrub s, gnetophytes , woody plant s in the genera Gnetum , Welwitschia , and Ephedra genus Ephedra , and angiosperms , the flowering plants, a large group including many familiar plants in a wide variety of habitats. In addition to the taxa listed above, the fossil record contains evidence of many extinct taxa of seed plants. The so called seed ferns Pteridospermae were one of the earliest successful groups of land plants, and forests dominated by seed ferns were prevalent in the late Paleozoic . Glossopteris was the most prominent tree genus in the ancient southern supercontinent of Gondwana during the Permian period. By the Triassic period, seed ferns had declined in ecological importance, and representatives of modern gymnosperm groups were abundant and dominant through the end of the Cretaceous , when angiosperms radiated. Another Late Paleozoic group of probable spermatophytes were the gigantopterid s. Relationships and nomenclature see Gnetophyta Classification Seed bearing plants were traditionally divided into angiosperm s, or flowering plants, and gymnosperm s, which includes the gnetophytes, cycads, ginkgo, and conifers. Older morphological studies believed in a close relationship between the gnetophytes and the angiosperms, ref name ... more details
Name s Scope Description Embryophyte Land plant s, also known as Embryophyta or Metaphyta. Plantae ... organisms. The two groups of green algae are the closest relatives of land plants embryophyte s . The first ... label1 Embryophyte s 1 clade 1 clade label1 Stomatophytes 1 clade 1 clade label1 Polysporangiophyte ... 2 Ulvophyceae Embryophytes Main Embryophyte Image Ferns02.jpg thumb Dicksonia antarctica , a species ..., called embryophyte s. They include the vascular plant s, plants with full systems of leaf leaves ... more details
Image C elegans stained.jpg 250px thumb right In this image, a wild type Caenorhabditis elegans is stained to highlight the nuclei of its cells. Multicellular organisms are organism s that consist of more than one cell biology cell , in contrast to single celled organism s. Most life that can be seen with the naked eye is multicellular, as are all animal s except for specialized organisms such as Myxozoa and Embryophyte land plants . Evolutionary history Multicellularity has evolved independently dozens of times in the history of Earth, for example in plants and animal s. ref cite journal author Bonner, John Tyler authorlink John Tyler Bonner year 1998 title The Origins of Multicellularity journal Integrative Biology Issues, News, and Reviews volume 1 issue 1 pages 27 36 url http courses.cit.cornell.edu biog1101 outlines Bonner 20 Origin 20of 20Multicellularity.pdf format PDF, 0.2 MB issn 1093 4391 doi 10.1002 SICI 1520 6602 1998 1 1 27 AID INBI4 3.0.CO 2 6 ref Multicellularity exists in both prokaryote s and eukaryote s, and first appeared several billion years ago in cyanobacteria . In order to reproduce, true multicellular organisms must solve the problem of regenerating a whole organism from germ cell s i.e. sperm and ovum egg cells , an issue that is studied in developmental biology . Therefore, the development of sexual reproduction in unicellular organisms during the Mesoproterozoic is thought to have precipitated the development and rise of multicellular life. Citation needed date May 2010 Multicellular organisms, especially long living animals, also face the challenge of cancer , which occurs when cells fail to regulate their growth within the normal program of development. Changes in tissue morphology can be observed during this process. Hypotheses for origin There are various mechanisms by which multicellularity could have evolved. For now, there s little evidence to support choosing one of them as the first to evolve. One hypothesis is that a group of fu ... more details
Automatic taxobox fossil range Geological range linked Wenlock Early Devonian ref ref name Edwards1980 ref name Boyce2008 image Cooksonia pertoni.png image caption A cartoon of Cooksonia , reconstructed with non photosynthetic axes, dependent on its gametophyte, as per Boyce 2008 taxon Cooksonia authority Lang 1937 emend. Gonez & Gerrienne 2010 ref name GonezGerrienne2010a display parents 3 show that it s an embryophyte to clarify what Kingdom Plantae means here subdivision ranks Species subdivision species list C. pertoni Lang 1937 C. hemisphaerica Lang 1937 C. cambrensis Edwards 1979 C. bohemica Schweitzer 1980 C. paranensis Gerrienne et al. 2001 C. banksii Habgood et al. 2002 C. caledonica and C. crassiparietilis removed see article Cooksonia is an extinct grouping of primitive land plant s. The earliest Cooksonia date from the middle of the Silurian the Wenlock epoch ref name Edwards1980 cite journal author D. Edwards year 1980 title Records of Cooksonia type sporangia from late Wenlock strata in Ireland journal Nature volume 287 pages 41 42 doi 10.1038 287041a0 last2 Feehan first2 J. ref the group continues to be an important component of the flora until the Early Devonian , a total time span of Period span brief Wenlock Early Devonian . For historical reasons, while Cooksonia fossils are distributed globally, most type specimen s come from Britain. Description The first Cooksonia species were described by William Henry Lang in 1937 and named in honor of Isabel Clifton Cookson Isabel Cookson , with whom he had collaborated, and who collected specimens of Cooksonia pertoni in Perton Quarry in 1934. ref name Lang1937 Only the sporophyte phase of Cooksonia is currently known. Individuals were small, a few centimetres tall, and had a simple structure they lacked leaves, flowers and roots although it has been speculated that they grew from an unpreserved rhizome. ref name Boyce2008 They had a simple stalk, that branched dichotomously a few times. Each branch ended i ... more details
diverged from all other embryophyte plants near the beginning of their evolution . The strongest ... liverwort. center gallery See also Bryophyte Embryophyte References Reflist 2 External links Commons ... more details
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