Käklösa fiskar

Käklösa fiskar
Stratigrafisk utbredning: Tidig kambrium - Nutid
Systematik
DomänEukaryoter
Eukaryota
RikeDjur
Animalia
StamRyggsträngsdjur
Chordata
UnderstamRyggradsdjur
Vertebrata
ÖverklassKäklösa fiskar
Agnatha
Vetenskapligt namn
§ Agnatha
Klasser
Hitta fler artiklar om djur med

Käklösa fiskar (Agnatha) är en grupp fiskar som tillhör understammen ryggradsdjur. Det är en grupp som dök upp på jorden för drygt 500 miljoner år sedan, under Kambrium. De brukar kallas pansarrundmunnar och tillhör de käklösa fiskarna. Under Devonperioden för ungefär 350 miljoner år sedan konkurrerades de flesta arterna av käklösa fiskar ut. Nejonögon och pirålar är nu levande arter av käklösa fiskar. Totalt finns det endast ett femtiotal arter på jorden idag.[1]

Egenskaper

De viktigaste kännetecknen för Agnatha, genom vilka de avviker från Gnathostomata är att näsgången är oparig och har gemensam mynning med hypofysgången, munnen saknar verkliga käkar, gälarna är säckformiga, det inre skelettet är broskigt och att egentliga gälbågar saknas. Även extremiteter saknas, men dock finns hos en del fossila former ett främre par fenlika bihang, som dock kanske ej är homologa med fiskarnas bröstfenor.[2]

Klasser

Referenser

  1. ^ ”Käklösa fiskar (Agnata) - De första fiskarna”. http://www9.vgregion.se/vastarvet/gnm/evolution/rund1.htm. Läst 28 november 2014. 
  2. ^ Svensk Uppslagsbok, Band 1, 1947-1955. (spalt 329)
  3. ^ Sara Eliason. Solstenar och kattskallar - Gotländsk fossil- och geologiguide. sid. 112 
  4. ^ Shubin, Neil (2009). Your Inner Fish: A Journey into the 3.5 Billion Year History of the Human Body. Pantheon Books, New York. sid. 85–86. ISBN 978-0-30-727745-9 
  5. ^ William Antony S. Sarjeant, L. B. Halstead (1995) (på engelska). Vertebrate fossils and the evolution of scientific concepts: writings in tribute to Beverly Halstead. Gordon & Breach. ISBN 978-2-88124-996-9. http://books.google.com/?id=B3leE3TTeuIC&pg=PA146. Läst 28 november 2014 
  6. ^ P. C. J. Donoghue, M. P. Smith (2001). ”The anatomy of Turinia pagei (Powrie), and the phylogenetic status of the Thelodonti” (på engelska). Transactions of the Royal Society of Edinburgh: Earth Sciences 92 (1): sid. 15–37. doi:10.1017/S0263593301000025. http://www.ingentaconnect.com/content/rse/tes/2001/00000092/00000001/art00002. Läst 28 november 2014. 

Externa länkar

Read other articles:

G-numbers redirects here. For other uses, see G (number). List of G series military vehicles redirects here. For other uses, see G series. front cover G1 1930 This is the Group G series List of the United States military vehicles by (Ordnance) supply catalog designation, — one of the alpha-numeric Standard Nomenclature Lists (SNL) that were part of the overall List of the United States Army weapons by supply catalog designation, a Supply Catalog that was used by the United States Army Ordna...

 

Questa voce sull'argomento cestisti sudcoreani è solo un abbozzo. Contribuisci a migliorarla secondo le convenzioni di Wikipedia. Segui i suggerimenti del progetto di riferimento. Kim Jong-gyu Kim con la maglia della Corea del Sud Nazionalità  Corea del Sud Altezza 206 cm Peso 98 kg Pallacanestro Ruolo Centro Squadra  Wonju DB Promy Carriera Giovanili Kyung Hee University Squadre di club 2013-2019 Changwon Sakers2019- Wonju DB Promy Nazionale 2011- Corea del Sud Pal...

 

Fiore di Cassia La floricoltura o arte di coltivare i fiori, è un settore dell'agricoltura che ha lo scopo di produrre per il giardinaggio o il commercio, fiori recisi, piante fiorite in vaso o cassetta, materiale per la propagazione come semi, bulbi, tuberi, rizomi, ecc. Può essere praticata per hobby o come attività professionale. Le coltivazioni possono avvenire in vaso, in piena terra, in serra oppure in giardini all'aperto. L'umanità fin dai tempi antichi ha praticato la floricoltura...

Sebuah cuplikan dari kehidupan Petrus dari Verona: Seorang pria bisu secara ajaib disembuhkan Kesembuhan ilahi adalah praktek dua dan gerak tubuh (seperti penumpangan tangan) yang diyakini oleh beberapa orang memperuntukkan campur tangan ilahi dalam penyembuhan spiritual dan fisik, khususnya praktek Kristen.[1] Para orang percaya menganggap bahwa kesembuhan penyakit dan kecacatan dapat dilakukan lewat keyakinan agama melalui doa dan/atau ritual lainnya Catatan Referensi ^ Faith healin...

 

Not to be confused with AM broadcasting. AM RadioBackground informationOriginLos Angeles, California, U.S.GenresAlternative rock, alternative metalYears active2001–presentLabelsPPBaba MusicMembersKevin RidelJason MooreJustin FisherFrank ReinaPast membersGuy HarringtonAdam HurlbutJoe HigginsRowan RobertsonBryce SoderbergFrancesca Po Dan Flutur Juan RamirezWebsiteOfficial Site AM Radio is an American alternative rock band from Los Angeles, California. History AM Radio,[1][2] f...

 

Andréi Voznesenski En el Miami Book Fair International, 1990.Información personalNombre en ruso Андрей Вознесенский Nacimiento 12 de mayo de 1933Moscú, URSSFallecimiento 1 de junio de 2010 (77 años)Moscú, RusiaCausa de muerte Accidente cerebrovascular Sepultura Cementerio Novodévichi Nacionalidad RusiaRusiaLengua materna Ruso EducaciónEducado en Instituto de Arquitectura de Moscú Información profesionalOcupación poetaMovimiento ModernismoLengua literaria rusoG...

For the Greek footballer, see Konstantinos Georgakopoulos (footballer). Konstantinos GeorgakopoulosΚωνσταντίνος ΓεωργακόπουλοςKonstantinos GeorgakopoulosMinister of Education of GreeceIn officeAugust 6, 1936 – November 25, 1938Prime MinisterIoannis MetaxasCaretaker Prime Minister of GreeceIn officeMarch 3, 1958 – May 17, 1958Preceded byConstantine KaramanlisSucceeded byConstantine Karamanlis Personal detailsBorn(1890-12-26)26 December 1890Tripol...

 

Terowongan ChannelTerminal Britania di Cheriton, dari Pilgrims' WayIkhtisarLokasiDi bawah Selat DoverStatusAktifMulaiCalais, PerancisBerakhirFolkestone, Britania RayaOperasiMulai dibangun16 Februari 1987Dibuka6 Mei 1994Lalu lintasKeretaTeknisPanjang50 kilometer (31 mi)Lebar sepur1.435 mmKelajuan yang diizinkan300 km/h (185 mph) Terowongan Channel (Bahasa Inggris: Channel Tunnel; Bahasa Prancis: le tunnel sous la Manche) adalah sebuah terowongan rel sepanjang 50 kilometer di baw...

 

Constituency of the Madhya Pradesh legislative assembly in India HuzurConstituency for the Madhya Pradesh Legislative AssemblyConstituency detailsCountryIndiaRegionCentral IndiaStateMadhya PradeshDistrictBhopalLS constituencyBhopalEstablished2008ReservationNoneMember of Legislative Assembly16th Madhya Pradesh Legislative AssemblyIncumbent Rameshwar Sharma PartyBharatiya Janata Party Huzur is one of the 230 assembly constituencies of Madhya Pradesh. It is a part of Bhopal district and came int...

獲得メダル 1966年世界選手権 体操競技 オリンピック 金 1968 メキシコシティー 男子団体 銅 1968 メキシコシティー 男子床 世界体操競技選手権 金 1966 ドルトムント 男子団体 金 1970 リュブリャナ 男子団体 銀 1966 ドルトムント 男子跳馬 銅 1966 ドルトムント 男子あん馬 銅 1970 リュブリャナ 男子床 銅 1970 リュブリャナ 男子跳馬 加藤 武司(かとう たけし、1942年9月25日 - 1982...

 

У этого термина существуют и другие значения, см. Good Friday (значения). Великая пятница Распятие Христово (фреска Феофана Критянина в Крестоникитском монастыре Афона) Тип Седмичный день Дата пятница Страстной седмицы В 2022 15 апреля (католицизм) 9 апреля (22 апреля) (православие) ...

 

خايمي (بالإسبانية: Jaime de Borbón y Battenberg)‏  معلومات شخصية اسم الولادة (بالإسبانية: Jaime Leopoldo Isabelino Enrique Alejandro Alberto Alfonso Víctor Acacio Pedro Pablo María de Borbón y Battenberg)‏  الميلاد 23 يونيو 1908(1908-06-23)شقوبية الوفاة 20 مارس 1975 (66 سنة)سانت غالن سبب الوفاة سقوط  [لغات أخرى]‏  مكان الدفن بانتيون ...

Cosmin Contra Contra as a Getafe playerInformasi pribadiNama lengkap Cosmin Marius ContraTanggal lahir 15 Desember 1975 (umur 47)Tempat lahir Timişoara, RomaniaTinggi 180 m (590 ft 7 in)Posisi bermain Right back / MidfielderKarier junior1988–1993 Politehnica TimișoaraKarier senior*Tahun Tim Tampil (Gol)1993–1995 Politehnica Timișoara 51 (1)1996–1999 Dinamo Bucureşti 101 (8)1999–2001 Alavés 66 (5)2001–2002 Milan 29 (3)2002–2006 Atlético Madrid 34 (0)2004...

 

Olympus PEN E-PM2OverviewMakerOlympus CorporationSensor/mediumSensor typeCMOSSensor size17.3 x 13mm (Four Thirds type)Maximum resolution4608 x 3456 (16 megapixels)Film speed100-25600Recording mediumSD/SDHC/SDXCFocusingFocus areas35 focus pointsShutterShutter speeds1/4000s to 60sContinuous shooting8 frames per secondImage processingWhite balanceYesGeneralLCD screen3 inches with 460,000 dotsDimensions110 x 64 x 34mm (4.33 x 2.52 x 1.34 inches)Weight269g including battery The Olympus PEN E-PM2 i...

 

Church in Shropshire, England Church in Shrewsbury, United KingdomSt Chad's Church, ShrewsburyThe current building of St Chad's Church, Shrewsbury, seen from The QuarryLocationSt Chad's Terrace, Shrewsbury, SY1 1JXCountryUnited KingdomDenominationChurch of EnglandPrevious denominationRoman Catholic Celtic ChristianityChurchmanshipLiberal CatholicWebsitewww.stchadschurchshrewsbury.comHistoryFoundedc560Founder(s)? Brochwel Ysgithrog;? King OffaArchitectureHeritage designationGrade IDesignated10...

Species of honeysuckle plant Lonicera xylosteum Scientific classification Kingdom: Plantae Clade: Tracheophytes Clade: Angiosperms Clade: Eudicots Clade: Asterids Order: Dipsacales Family: Caprifoliaceae Genus: Lonicera Species: L. xylosteum Binomial name Lonicera xylosteumL. Lonicera xylosteum Lonicera xylosteum, commonly known as fly honeysuckle,[1] European fly honeysuckle, dwarf honeysuckle[2] or fly woodbine is a deciduous shrub.[1] The glossy red (or occasio...

 

Number of minor planets and comets visited by spacecraft The following tables list all minor planets and comets that have been visited by robotic spacecraft. List of minor planets visited by spacecraft A total of 18 minor planets (asteroids, dwarf planets, and Kuiper belt objects) have been visited by space probes. Moons (not directly orbiting the Sun) and planets are not minor planets and thus are not included in the table below. Minor planets and comets visited by spacecraft as of 2019 (exc...

 

Bài viết này là một bài mồ côi vì không có bài viết khác liên kết đến nó. Vui lòng tạo liên kết đến bài này từ các bài viết liên quan; có thể thử dùng công cụ tìm liên kết. (tháng 8 năm 2020) Lễ hội Opera BydgoszczLễ hội Opera Bydgoszcz (tiếng Ba Lan: Bydgoski Festiwal Operowy) là sự kiện văn hóa thường niên về nghệ thuật opera và múa ba lê ở thành phố Bydgoszcz. Đặc điểm Buổi biểu diễn Ca...

Poveri ma belliRenato Salvatori e Maurizio Arena in una scena del filmPaese di produzioneItalia, Francia Anno1957 Durata101 min Dati tecniciB/Nrapporto: 1,37:1 Generecommedia RegiaDino Risi SoggettoDino Risi SceneggiaturaPasquale Festa Campanile, Massimo Franciosa, Dino Risi ProduttoreSilvio Clementelli Casa di produzioneTitanus, S.G.C. Distribuzione in italianoTitanus FotografiaTonino Delli Colli MontaggioMario Serandrei MusicheGiorgio Fabor ScenografiaPiero Filippone CostumiBeni Montres...

 

American actor Santino FontanaBornSantino Anthony FontanaCalifornia, U.S.[1]Alma materUniversity of Minnesota (BFA)Occupations Actor singer Years active2007–presentSpouse Jessica Hershberg ​(m. 2015)​Children1[2] Santino Fontana is an American actor and singer. He began his career in 2007 and soon gained wide acclaim for his leading performances on Broadway and Off-Broadway. He has received a Tony Award, two Drama Desk Awards, an Outer ...

 

Strategi Solo vs Squad di Free Fire: Cara Menang Mudah!