Uhlobo Chordates: isakhiwo kanye nasekuthuthukisweni kwezwekazi lase Amphioxus

Kutfutfukiswa Amphioxus futhi isikhundla salo ehlelekile isikhathi eside ayikaziwa. Manje ososayensi nizokwazi ngokuqinisekile ukuthi lo imelele uhlobo Chordates ukuthuthukiswa engesobala.

izici Jikelele uhlobo Chordates

Fish, izilwane eziphila emanzini nasezweni, ezihuquzelayo, izinyoni, izilwane ezincelisayo - zonke lezi zilwane ezimela uhlobo Chordates. What esihlanganisa eziphilayo ehlukene kangaka? It kuvela ukuthi zonke zibe uhlelo ezivamile isakhiwo.

Emongweni somzimba lwamathambo Axial, othiwa kuzithinta. Ngo Amphioxus ubelesela kukho konke ukuphila. Ngenhla kuzithinta kuyinto neural tube. Phakathi yokuguqukela kwesinye isimo iningi abameleli uhlobo kwakhiwa emgogodleni ingqondo it is. Ngaphansi Axial skeleton amathumbu emise njengoba ngamapayipi. Uqhoqhoqho kuzithinta kukhona izimbotshana gill. Ngo zilwane ezihlala emanzini, lesi sici lugcinwa, ngenkathi izwe sici kuphela yentuthuko sombungu.

Umlando yokutholakala Amphioxus

Kungani Amphioxus ukuthuthukiswa isikhathi eside yabangela impikiswano nemibuzo? Iqiniso liwukuthi isikhathi eside ukuthi lalibhekwa njengendawo silwanyana. Amphioxus (isithombe ngezansi sibonisa Sakhiwo sangaphandle yayo) ubukeka ngempela lezi zilwane. Unomzimba esingeke ezithambile ayevumela futhi uhlala imvelo yasemanzini - emanzini wezilwandle nasolwandle. Kodwa ikakhulukazi inhlangano yangaphakathi kube lula ukubona ukuthi nabo ehlukile amayunithi ehlelekile.

Ngaphezu kwalokho, ngenxa yemizamo Petra Pallasa futhi Aleksandra Kovalevskogo kwatholakala ukuthi lezi zilwane amadlozi yezilwane ezinomgogodla yesimanje. Ososayensi shayela la magciwane izinsalela zamathambo ophilayo. Kukholakala ukuthi lancelet hhayi kwazivelela, njengoba ingashintshwa ngokuphelele imvelo nendlela yempilo ngokungabi bikho izimbangi.

Izici Ezihilelekile Kule Sakhiwo sangaphandle

Ngenxa komzimba lalesi silwane ke linegama engavamile - lancelet. Photo ebonisa ukuthi umzimba ufana ithuluzi kuhlinzwa lasendulo ukuthi iloliwe nhlangothi zombili. Ibizwa ngokuthi i-Lancet. Lokhu ukufana kahle utjengisa ukukhambelana izici Sakhiwo sangaphandle.

Amphioxus umzimba ifinyelela umkhawulo wobude 8 cm. It hemmed izinhlangothi wamkhomba ekupheleni. Kolunye uhlangothi kule mpi we longitudinal nesibaya umzimba yakha amaphiko - amaphiko futhi caudal. Lancelet ekupheleni ezingemuva umzimba ungcwatshwa isihlabathi. On the front kuyinto wentaba preoral, sizungezwe ihambe.

Skeleton kanye nemisipha

Kutfutfukiswa Amphioxus libhekene aphikelele kuzithinta kukho konke ukuphila kwakhe. Ngo umucu ke welula kuwo wonke umzimba kusukela ngaphambili kuze kube sekupheleni labaqaphi elingemuva. Kuzo zombili izinhlangothi kuzithinta ahlelwe ezintweni eziningi imisipha. Lokhu Ukwakheka kohlelo locomotor ivumela Amphioxus ukuhambisa efanayo. Muscle Kufinyeta kuholele eguqa yomzimba, futhi esebenzisa imisindo kuyinto ukulungiswa kwananoma yayo.

sakhiwo sangekhatsi

emizimbeni Amphioxus yakha zonke izinhlelo bokuphila. Wokugaya ukudla ethulwa ukuvulwa temlomo, emphinjeni kanye namathumbu ngokusebenzisa-tube ne yayifanekisela nomxhantela hepatic, okuyinto wenza umsebenzi we endlaleni engasesinyeni. Ngu hlobo lwamandla Amphioxus kukhona heterotrophic isihlungi esebenza ngogesi. Le nqubo Ihlobene ngokuseduze ukuphefumula, okuyinto eyenziwa ngokusebenzisa gills kanye umzimba wonke ebusweni.

Ngo ingaphakathi okolozhabernuyu eziyishumi nemitshingo Ukukhetha evulekile. Basuke emelelwa amashubhu eziningi abhanqiwe - Nephridia. Amphioxus isimiso sokujikeleza kwegazi angavaliwe. Siqukethe izitsha ventral kanye amaphiko.

izitho Amphioxus zokuzala ngokuthi gonads. Lokhu nezindlala abhanqiwe okukhishwa ezingasetshenziswa afinyelela 25. Amphioxus yizilwane dioecious. Ngakho-ke, ukuthuthukisa amaqanda noma testes. Amapayipi zangasese, lezi zilwane akudingeki. Ngakho-ke, amaseli faka ingaphakathi ngesikhathi gonads ikhefu okolozhabernuyu noma izindonga umzimba.

Lokuzaliswa nokuthuthukiswa

Izitho zokuzala ka Amphioxus ukunikeza kokukhulelwa zabo zangaphandle. Gametes zitholakala emanzini, lapho coalesce. Izinsikazi amaqanda ngemva kokushona kwelanga kuzo zonke izinkathi zonyaka ngaphandle ebusika. germ cells yabo aqukethe kancane kakhulu Iqanda isikhuphasha libhekene usayizi encane - mayelana 100 microns.

Ngisho nangaphambi kokuba ukuchotshozwa okuqukethwe Iqanda Amphioxus umahluko ku ezintathu izingqimba lwegciwane: ecto, Meso futhi endoderm. Phakathi ukwahlukana okwalandela ngamunye okuyinto yakha abafanele isitho uhlelo.

Kutfutfukiswa Amphioxus kunikeza umbono mayelana nezici yale nqubo e chordates. Siqukethe uchungechunge izinqubo ngokulandelana sokukhulelwa, cleavage, gastro futhi neurulation organogeneza.Razmnozhenie Amphioxus, kanye nentuthuko yabo eminye zihlobene kakhulu amanzi. Iqanda eselivundisiwe ezinsukwini 4-5 ekuthuthukiseni isibungu. It has a usayizi kuze kube 5mm futhi zintanta ngokukhululekile emanzini ngenxa cilia eziningi. Isigaba elalikudle lapho liseyisibungu sihlala 3 izinyanga. Ebusuku-ke antante phezulu amanzi, futhi emini nokucwila.

Amfioksidy - kangaka okuthiwa izibungu enkulu Amphioxus, okuyinto lo mkhuba isilwane emhlabeni. Okokuqala, base aphanjaniswe abadala. Kodwa ucwaningo oluningana kuphethwa ngokuthi bahlalaphi kuphela phezu yamanzi yokwakheka plankton. Amfioksidy elingase afinyelele 11 mm, ukugcina zonke izici izakhiwo elalikudle lapho liseyisibungu. umzimba wabo embozwe cilia, cishe ongakasetshenzwa tentacles temlomo okolozhabernaya umgodi futhi gonads.

Ngakho Amphioxus kukhona chordates bakudala zasolwandle. Basonta bescherepnyh subtype, ikilasi Golovohordovye. Amphioxus elinesimo yokuphila umzimba, ngokuba izilwane dioecious nge kokukhulelwa zangaphandle kanye nohlobo ongaqondile ukuthuthukiswa.