Dier: Verskil tussen weergawes

[[Geen|Genetiese]] studies het ons begrip van die verhouding tussen die diere in Bilateria aansienlik verander. Dit lyk of die meeste tot twee groot stambome behoort: DeuterostomaDeuterostomia en ProtostomaProtostomia; laasgenoemde sluit in die Ecdysozoa en Lophotrochozoa. Die Chaetognatha is aanvanklik as DeuterostomaDeuterostomia geklassifiseer, maar onlangse molekulêre studies het dié groep geëien as ’n basale ProtostomaProtostomia-lyn.<ref>{{Cite journal|title = Chaetognath phylogenomics: a protostome with deuterostome-like development|url = http://www.cell.com/current-biology/abstract/S0960-9822(06)01835-5 |journal = Current Biology|date = 8 August 2006|issn = 0960-9822|pmid = 16890510|pages = R577–R578|volume = 16|issue = 15|doi = 10.1016/j.cub.2006.07.016|first = Ferdinand|last = Marlétaz|first2 = Elise|last2 = Martin|first3 = Yvan|last3 = Perez|first4 = Daniel|last4 = Papillon|first5 = Xavier|last5 = Caubit|first6 = Christopher J.|last6 = Lowe|first7 = Bob|last7 = Freeman|first8 = Laurent|last8 = Fasano|first9 = Carole|last9 = Dossat}}</ref>

Daar is ook ’n paar klein groepe diere met bilaterale simmetrie met relatief kriptiese morfologie waarvan die verwantskap met ander diere nog nie baie duidelik is nie. So het onlangse molekulêre studies Acoelomorpha en ''Xenoturbella'' geëien as behorende tot ’n monofiletiese groep,<ref name="Hejnol">{{cite journal | last1 = Hejnol | first1 = A. | last2 = Obst | first2 = M. | last3 = Stamatakis | first3 = A. | last4 = Ott | first4 = M. | last5 = Rouse | first5 = G. W. | last6 = Edgecombe | first6 = G. D. | display-authors = 6 | last7 = et al | year = 2009 | title = Assessing the root of bilaterian animals with scalable phylogenomic methods | journal = Proceedings of the Royal Society B: Biological Sciences | volume = 276 | issue = | pages = 4261–4270 | doi=10.1098/rspb.2009.0896 | pmid=19759036 | pmc=2817096}}</ref><ref name="Philippe2011" /><ref name="Edgecombe 2011">{{Cite journal|last2=Giribet|first2=G.|last3=Dunn|first3=C. W.|last4=Hejnol|first4=A.|last5=Kristensen|first5=R. M.|last6=Neves|first6=R. C.|last7=Rouse|first7=G. W.|last8=Worsaae|first8=K.|last9=Sørensen|first9=M. V.|year=2011|title=Higher-level metazoan relationships: Recent progress and remaining questions|journal=Organisms Diversity & Evolution|volume=11|issue=2|pages=151–172 |doi=10.1007/s13127-011-0044-4|pmc=|pmid=|last1=Edgecombe|first1=G. D.}}</ref> maar daar is weinig ooreenstemming oor of die groep uit DeuterostomaDeuterostomia ontwikkel het,<ref name="Philippe2011">{{Cite journal | last1 = Philippe | first1 = H. | last2 = Brinkmann | first2 = H. | last3 = Copley | first3 = R. R. | last4 = Moroz | first4 = L. L. | last5 = Nakano | first5 = H. | last6 = Poustka | first6 = A. J. | last7 = Wallberg | first7 = A. | last8 = Peterson | first8 = K. J. | last9 = Telford | first9 = M. J. | title = Acoelomorph flatworms are deuterostomes related to ''Xenoturbella'' | journal = Nature | volume = 470 | pages = 255–258 | year = 2011 | pmid = 21307940 | doi = 10.1038/nature09676 |bibcode = 2011Natur.470..255P | issue=7333 | pmc=4025995}}</ref> en of dit ’n sustergroep van alle ander diere met bilaterale simmetrie (Nephrozoa) verteenwoordig.<ref name="Rouse 2016">{{cite journal |last=Rouse |first=Greg W. |last2=Wilson |first2=Nerida G. |last3=Carvajal |first3=Jose I. |last4=Vrijenhoek |first4=Robert C. |date=2016-02-03 |title=New deep-sea species of Xenoturbella and the position of Xenacoelomorpha |url=http://www.nature.com/nature/journal/v530/n7588/full/nature16545.html |journal=Nature |publisher= |volume= 530|issue=7588 |pages=94–97 |doi=10.1038/nature16545 |access-date=2016-02-03 |pmid=26842060|bibcode=2016Natur.530...94R }}</ref><ref name="Cannon 2016">{{cite journal |last=Cannon |first=Johanna T. |last2=Vellutini |first2=Bruno C. |last3=Smith III |first3=Julian. |last4=Ronquist |first4=Frederik |last5=Jondelius |first5=Ulf |last6=Hejnol |first6=Andreas |date=2016-02-03 |title=Xenacoelomorpha is the sister group to Nephrozoa |url=http://www.nature.com/nature/journal/v530/n7588/full/nature16520.html |journal=Nature |publisher= |volume= 530|issue=7588 |pages=89–93 |doi=10.1038/nature16520 |access-date=2016-02-03 |pmid=26842059|bibcode=2016Natur.530...89C }}</ref> Ander groepe met onsekere verwantskap sluit Rhombozoa en Orthonectida in. Een filum, Monoblastozoa, is in 1892 deur ’n wetenskaplike beskryf, maar tot dusver was daar geen verdere bewys dat dit bestaan nie.<ref>[http://www.the-scientist.com/?articles.view/articleNo/32652/title/Gone-Missing--circa-1892/ Gone Missing, circa 1892]</ref>

====DeuterostomaDeuterostomia en ProtostomProtostomia====

[[DeuterostomaDeuterostomia]] verskil in verskeie opsigte van [[ProtostomaProtostomia]]. Diere van albei groepe het ’n volledige spysverteringstelsel. By laasgenoemde groep ontwikkel die eerste opening wat in die embrio verskyn, in die mond en die tweede opening in die anus. In eersgenoemde groep ontwikkel die openinge andersom.<ref>{{cite book |last1=Peters |first1=Kenneth E. |last2=Walters |first2=Clifford C. |last3=Moldowan |first3=J. Michael |title=The Biomarker Guide: Biomarkers and isotopes in petroleum systems and Earth history |volume=2 |year=2005 |publisher=Cambridge University Press |isbn=978-0-521-83762-0 |page=717}}</ref> By die meeste ProtostomaProtostomia vul selle eenvoudig die binnekant van die [[gastrula]] in om die [[mesoderm]] te vorm, maar by DeuterostomaDeuterostomia vorm dit deur die [[invaginasie]] van die [[endoderm]].<ref>{{cite book|last=Safra|first=Jacob E.|title=The New Encyclopædia Britannica, Volume 1; Volume 3|year=2003|publisher=Encyclopædia Britannica|isbn=978-0-85229-961-6|page=767}}</ref> DeuterostomaDeuterostomia-embrio's ondergaan radiale kliewing (verdeling) en ProtostomaProtostomia spirale kliewing.<ref>{{cite journal|last=Valentine|first=James W.|date=July 1997|title=Cleavage patterns and the topology of the metazoan tree of life|journal=PNAS|publisher=The National Academy of Sciences|volume=94|pages=8001–8005|bibcode = 1997PNAS...94.8001V |doi = 10.1073/pnas.94.15.8001|pmid=9223303|pmc=21545|issue=15}}</ref>

Dit alles dui daarop dat DeuterostomaDeuterostomia en ProtostomaProtostomia twee aparte, monofiletiese stambome is. Die belangrikste filums van DeuterostomaDeuterostomia is [[Echinodermata]] en [[Chordata]].<ref>{{cite book|last=Hyde|first=Kenneth|title=Zoology: An Inside View of Animals|year=2004|publisher=Kendall Hunt|isbn=978-0-7575-0997-1|page=345}}</ref> Eersgenoemde is radiaal simmetries en uitsluitlik seediere, soos [[seester]]re, [[seekastaiings]] en seekomkommers.<ref>{{cite book|last=Alcamo|first=Edward|title=Biology Coloring Workbook|year=1998|publisher=The Princeton Review|isbn=978-0-679-77884-4|page=220}}</ref> Chordata word deur die [[gewerweldes]], diere met rugstringe, oorheers.<ref>{{cite book|last=Holmes|first=Thom|title=The First Vertebrates|page=64|publisher=Infobase Publishing|year=2008|isbn=978-0-8160-5958-4}}</ref> Dit sluit in [[vis]]se, [[amfibie|amfibieë]], [[reptiel]]e, [[voël]]s en [[soogdier]]e.<ref>{{cite book|last=Rice|first=Stanley A.|title=Encyclopedia of evolution|publisher=Infobase Publishing|year=2007|page=75|isbn=978-0-8160-5515-9}}</ref>

DeuterostomaDeuterostomia sluit ook [[Hemichordata]], of die kraagdraers, in.<ref>{{cite book |last1=Tobin |first1=Allan J.|last2=Dusheck |first2=Jennie |title=Asking about life |year=2005 |publisher=Cengage Learning |isbn=978-0-534-40653-0 |page=497}}</ref><ref>{{Cite journal|title = Hemichordate genomes and deuterostome origins|url = http://www.nature.com/nature/journal/v527/n7579/full/nature16150.html|journal = Nature|date = 26 November 2015|issn = 0028-0836|pages = 459–465|volume = 527|issue = 7579|doi = 10.1038/nature16150|first = Oleg|last = Simakov|first2 = Takeshi|last2 = Kawashima|first3 = Ferdinand|last3 = Marlétaz|first4 = Jerry|last4 = Jenkins|first5 = Ryo|last5 = Koyanagi|first6 = Therese|last6 = Mitros|first7 = Kanako|last7 = Hisata|first8 = Jessen|last8 = Bredeson|first9 = Eiichi|last9 = Shoguchi|pmid=26580012|pmc=4729200|bibcode = 2015Natur.527..459S}}</ref> Hoewel hulle nie vandag juis volop is nie, behoort die belangrike fossiele [[graptoliet]]e dalk tot hierdie groep.<ref>{{cite book|last=Safra|first=Jacob E.|title=The New Encyclopædia Britannica, Volume 19|year=2003|publisher=Encyclopædia Britannica|isbn=978-0-85229-961-6|page=791}}</ref>

Die [[Ecdysozoa]] behoort tot ProtostomaProtostomia en is genoem na die algemene eienskap van groei deur vervelling.<ref>{{cite book |last=Dawkins |first=Richard |title=The Ancestor's Tale: A Pilgrimage to the Dawn of Evolution |year=2005 |publisher=Houghton Mifflin Harcourt |isbn=978-0-618-61916-0 |page=381}}</ref> Dit sluit die grootste dierfilum, die [[Arthropoda]], in en bevat [[insek]]te, [[spinnekop]]pe, [[krap]]pe, ens. Al dié diere se liggaam is in herhalende segmente verdeel wat gewoonlik in pare voorkom. Twee kleiner filums, Onychophora en Tardigrada, is nabye verwante en deel dié eienskappe. Ecdysozoa sluit ook die [[Nematoda]], of rondewurms, in wat dalk die tweede grootste dierfilum is. Rondewurms is meestal mikroskopies en kom voor in feitlik elke omgewing waar daar water is.<ref>{{cite book |last1=Prewitt |first1=Nancy L. |last2=Underwood |first2=Larry S. |last3=Surver |first3=William |title=BioInquiry: making connections in biology |year=2003 |publisher=John Wiley |isbn=978-0-471-20228-8 |page=289}}</ref> ’n Paar is belangrike parasiete.<ref>{{cite book |title=Parasites in social insects |year=1998 |publisher=Princeton University Press |isbn=978-0-691-05924-2 |last=Schmid-Hempel |first=Paul |page=75}}</ref> Kleiner filums wat aan hulle verwant is, is Nematomorpha, of die perdehaarwurms, Kinorhyncha, Priapulida en Loricifera. Hierdie groepe het ’n klein buikholte, wat ’n skynbuikholte genoem word.