Parallel evolutsiya

Parallel evolutsiya (parallel evolution) — bir-biri bilan yaqin qarindosh bo'lmagan, biroq o'xshash dastlabki belgiga (trait) ega bo'lgan alohida turlarda o'xshash evolyutsion bosim natijasida o'xshash xususiyatlarning rivojlanishidir.^[1]^[2]

Parallel va konvergent evolutsiya

Muayyan ajdoddan tarqalgan ikki naslning (lineage) har birida uchraydigan belgi berilgan bo'lsa, nazariy jihatdan parallel va konvergent evolyutsion tendensiyalarni qat'iy belgilash va ularni bir-biridan aniq farqlash mumkin.^[2] Biroq, amaliyotda konvergent evolutsiyani parallel evolutsiyadan farqlash mezonlari (criteria) noaniq bo'lganligi sababli, ixtiyoriy tashxis qo'yish holatlari ko'p uchraydi. Agar ikki tur o'xshash belgiga ega bo'lsa va ularning ajdodlari ham ushbu o'xshashlikka ega bo'lganligi ma'lum bo'lsa, evolutsiya parallel deb ta'riflanadi; agar bunday bo'lmasa, u konvergent deb hisoblanadi. Shunga qaramay, ko'rsatilgan shartlar daraja masalasidir, chunki barcha organizmlar umumiy ajdodlarga ega. Olimlar bu farqlashning foydali ekanligi borasida turlicha fikrda.^[3]^[4]

Xaltali va yo'ldoshli sutemizuvchilar o'rtasidagi parallel evolutsiya

Parallel evolutsiyaga oid ko'plab misollarni sutemizuvchilar (mammals) guruhining ikki asosiy tarmog'i — yo'ldoshli sutemizuvchilar (placentals) va xaltali sutemizuvchilar (marsupials) misolida ko'rish mumkin. Taxminan 100 million yil avval Gondvana (Gondwanaland) kabi quruqlik massalarining parchalanishidan so'ng, ushbu ikki guruh mustaqil evolyutsion yo'llarni bosib o'tgan. Janubiy Amerikada xaltalilar va yo'ldoshlilar bitta ekotizimni baham ko'rganlar (Katta Amerika almashinuvi (Great American Interchange) davrigacha); Avstraliyada xaltalilar ustunlik qilgan; Eski Dunyo va Shimoliy Amerikada esa yo'ldoshli sutemizuvchilar g'olib chiqqan. Shunga qaramay, barcha ushbu hududlarda sutemizuvchilar kichik bo'lgan va oltmish besh million yil oldingi Bo'r-paleogen qirg'ini (Cretaceous–Paleogene extinction event) natijasida dinozavrlar yo'q bo'lib ketgunga qadar ekotizimda cheklangan o'rinlarni egallagan. Bu vaqtga kelib, uchala quruqlikdagi sutemizuvchilar ham rang-barang shakllar va rollarni egallay boshlagan. Ba'zi shakllar har bir muhit uchun xos bo'lsa-da, ajratilgan qit'alarda ko'pincha hayratlanarli darajada o'xshash hayvonlar paydo bo'lgan. Bunga misol sifatida yo'ldoshli qilich tishli mushuklar (Machairodontinae) va Janubiy Amerikaning xaltali qilich tishli hayvoni (Thylacosmilus); Tasmaniya bo'risi (Tasmanian wolf) va Yevropa bo'risini keltirish mumkin. Shuningdek, xaltali va yo'ldoshli ko'rsichqonlar (moles), uchar tiyinlar (flying squirrels) va (bahsli bo'lsa-da) sichqonlar ham shular jumlasidandir.

Kolibri va nektarxo'rlar o'rtasida ekologik gildiyalarning shakllanishiga hissa qo'shuvchi belgilarning parallel koevolyutsiyasi

Yangi va Eski Dunyodagi nektarxo'rlar (nectarivore) qushlarning ikki tarmog'i — kolibrilar (hummingbirds) va nektarxo'rsimonlar (sunbirds) bir qator ixtisoslashgan xulq-atvor ekologiyasi (behavioral ecology) va anatomiya (anatomical) belgilarini parallel ravishda rivojlantirgan. Bu belgilar (tumshuq shakli, hazm qilish fermentlari va parvoz) qushlarga ular egallagan gul bilan oziqlanish va changlatish ekologik nishasiga (ecological niche) optimal tarzda moslashish imkonini beradi. Shunday qilib, qushlar o'rtasida parallel ravishda shakllangan koevolyutsion xulq-atvor sindromi yuqori darajada ixtisoslashgan qushlar va moslashgan o'simliklardan iborat emergensiya (emergent) gildiyasini (guild) yaratadi. Bunda Eski va Yangi Dunyoda ham har bir tomon gullarning changlanishidagi o'zaro hamkorlikdan foydalanadi.^[5]

Nektarxo'rlarning uzun va ninasimon tumshuq (bill) shakli ularga gulning urug'chisi yoki changchisi (pistil/stamen) tubiga yetib borish va ichidagi nektarni olish imkonini beradi. Nektarxo'rlar, shuningdek, o'zlarining ixtisoslashgan tumshuqlaridan «nektar o'g'irlash» (nectar robbing) uchun ham foydalanishlari mumkin. Bu amaliyot kolibrilarda ham, nektarxo'rlarda ham kuzatiladi. Bunda qush tumshug'ini standart usulda gulning naychasi orqali kiritish o'rniga, naychaning asosida teshik ochish orqali nektarni oladi. Shunday qilib, qush gulni changlatmasdan nektarni «o'g'irlaydi».^[6]

Nektarxo'rlar va ornitofil (ornithophilous) gullar ko'pincha qushning tumshug'i shakli, oziq manbasi va hazm qilish qobiliyati gulning naycha shakli va havoda muallaq turuvchi yoki qo'nuvchi qushlar tomonidan changlanishga moslashuvi bilan uyg'unlashgan mutualistik gildiya munosabatlarida bo'ladi. Qushlar o'zlarining uzun va ingichka tumshuqlari yordamida nektar iste'mol qiladilar va shu jarayonda tumshuqlariga chang to'playdilar; bu chang keyinchalik ular oziqlanadigan keyingi gulga o'tkaziladi. Ushbu mutualizm Eski Dunyo va Yangi Dunyo qushlari hamda ularning tegishli gullari o'rtasida parallel ravishda koevolyutsiyaga uchragan.^[7] Bundan tashqari, nektarxo'rlardagi hazm qilish fermenti faolligi o'z gullaridagi nektar tarkibiga mos kelishi qit'alar bo'ylab o'simliklar va changlatuvchilar o'rtasida parallel ravishda koevolyutsiyaga uchragan ko'rinadi. Chunki nektarxo'r nasllar mustaqil ravishda o'z gullariga xos nektarni hazm qilish qobiliyatini rivojlantirgan va bu alohida gildiyalarning shakllanishiga olib kelgan.^[7]^[8]

Nektarxo'rlarning saxarozani (sucrose) hazm qilish qobiliyati boshqa qush taksonlariga (taxa) qaraganda ancha yuqori. Bu farq saxarozani gidroliz (hydrolysis) qiluvchi ferment — saxaraza-izomaltazaning (sucrase-isomaltase) analogik yuqori konsentratsiyasi bilan bog'liq. Ichak yuzasining birlik maydoniga to'g'ri keladigan saxaraza faolligi nektarxo'rlarda boshqa qushlarga qaraganda yuqoriroq ekanligi aniqlangan, bu esa ushbu nektarxo'r qushlarning boshqa taksonlarga qaraganda ko'proq saxarozani tezroq hazm qila olishini anglatadi.^[8] Bundan tashqari, Adaptiv modulyatsiya gipotezasi (Adaptive Modulation Hypothesis) nektarxo'rlar va shakarni hazm qiluvchi fermentlar uchun qo'llanilmaydi, bu esa ikki nektarxo'r naslning har ikkalasi ham nektar bilan oziqlansa-da, ularning har ikkisida ham yuqori saxaraza-izomaltaza konsentratsiyasi bo'lishi shart emasligini anglatadi. Shunday qilib, analogik saxaroza hazm qilish qobiliyatining parallel ravishda egallanishi oqilona xulosa hisoblanadi, chunki ikki naslning ushbu yuqori ferment konsentratsiyasiga ega bo'lishi uchun boshqa aniq sabab yo'q.^[9]

Manbalar

↑ Parallel evolution, an example may be the Pyrotherians evolved a body plan similar to proboscideans: Online Biology Glossary (Wayback Machine saytida 2007-07-13 sanasida arxivlangan)
↑ ^2,0 ^2,1 Zhang, J. and Kumar, S. 1997. Detection of convergent and parallel evolution at the amino acid sequence level (Wayback Machine saytida 2016-03-03 sanasida arxivlangan). Mol. Biol. Evol. 14, 527-36.
↑ Arendt, J.; REZNICK, D. (January 2008). "Convergence and parallelism reconsidered: what have we learned about the genetics of adaptation?". Trends in Ecology & Evolution 23 (1): 26–32. doi:10.1016/j.tree.2007.09.011. PMID 18022278.
↑ Pearce, T. (10 November 2011). "Convergence and Parallelism in Evolution: A Neo-Gouldian Account". The British Journal for the Philosophy of Science 63 (2): 429–448. doi:10.1093/bjps/axr046.
↑ Janeček, Štěpán; Chmel, Kryštof; Uceda Gómez, Guillermo; Janečková, Petra; Chmelová, Eliška; Sejfová, Zuzana; Luma Ewome, Francis (February 2020). "Ecological fitting is a sufficient driver of tight interactions between sunbirds and ornithophilous plants". Ecology and Evolution 10 (4): 1784–1793. doi:10.1002/ece3.5942. ISSN 2045-7758. PMID 32128116. PMC 7042734. //www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=7042734.
↑ Juan Francisco Ornelas. Serrate Tomia: An Adaptation for Nectar Robbing in Hummingbirds?. The Auk, Volume 111, Issue 3, January 1994, pp. 703-710.
↑ ^7,0 ^7,1 Janeček, Štěpán; Bartoš, Michael; Njabo, Kevin Yana (2015-01-22). "Convergent evolution of sunbird pollination systems of Impatiens species in tropical Africa and hummingbird systems of the New World". Biological Journal of the Linnean Society 115 (1): 127–133. doi:10.1111/bij.12475. ISSN 0024-4066.
↑ ^8,0 ^8,1 McWhorter, Todd J.; Rader, Jonathan A.; Schondube, Jorge E.; Nicolson, Susan W.; Pinshow, Berry; Fleming, Patricia A.; Gutiérrez-Guerrero, Yocelyn T.; Martínez del Rio, Carlos (July 2021). "Sucrose digestion capacity in birds shows convergent coevolution with nectar composition across continents". iScience 24 (7). doi:10.1016/j.isci.2021.102717. ISSN 2589-0042. PMID 34235412. PMC 8246690. //www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=8246690.
↑ Karasov, W. H. (1992-09-01). "Tests of the adaptive modulation hypothesis for dietary control of intestinal nutrient transport" (en). American Journal of Physiology. Regulatory, Integrative and Comparative Physiology 263 (3): R496–R502. doi:10.1152/ajpregu.1992.263.3.R496. ISSN 0363-6119. PMID 1415633. https://www.physiology.org/doi/10.1152/ajpregu.1992.263.3.R496.

Izohlar

Dawkins, R. 1986. The Blind Watchmaker. Norton & Company.
Mayr. 1997. What is Biology. Harvard University Press
Schluter, D., E. A. Clifford, M. Nemethy, and J. S. McKinnon. 2004. Parallel evolution and inheritance of quantitative traits. American Naturalist 163: 809–822.
McGhee, G.R. 2011. Convergent Evolution: Limited Forms Most Beautiful. Vienna Series in Theoretical Biology, Massachusetts Institute of Technology Press, Cambridge (MA). 322 pp.

[1] Parallel evolution, an example may be the Pyrotherians evolved a body plan similar to proboscideans: Online Biology Glossary (Wayback Machine saytida 2007-07-13 sanasida arxivlangan)

[Zhang-2] 2,0 ^2,1 Zhang, J. and Kumar, S. 1997. Detection of convergent and parallel evolution at the amino acid sequence level (Wayback Machine saytida 2016-03-03 sanasida arxivlangan). Mol. Biol. Evol. 14, 527-36.

[3] Arendt, J.; REZNICK, D. (January 2008). "Convergence and parallelism reconsidered: what have we learned about the genetics of adaptation?". Trends in Ecology & Evolution 23 (1): 26–32. doi:10.1016/j.tree.2007.09.011. PMID 18022278.

[4] Pearce, T. (10 November 2011). "Convergence and Parallelism in Evolution: A Neo-Gouldian Account". The British Journal for the Philosophy of Science 63 (2): 429–448. doi:10.1093/bjps/axr046.

[5] Janeček, Štěpán; Chmel, Kryštof; Uceda Gómez, Guillermo; Janečková, Petra; Chmelová, Eliška; Sejfová, Zuzana; Luma Ewome, Francis (February 2020). "Ecological fitting is a sufficient driver of tight interactions between sunbirds and ornithophilous plants". Ecology and Evolution 10 (4): 1784–1793. doi:10.1002/ece3.5942. ISSN 2045-7758. PMID 32128116. PMC 7042734. //www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=7042734.

[6] Juan Francisco Ornelas. Serrate Tomia: An Adaptation for Nectar Robbing in Hummingbirds?. The Auk, Volume 111, Issue 3, January 1994, pp. 703-710.

[:0-7] 7,0 ^7,1 Janeček, Štěpán; Bartoš, Michael; Njabo, Kevin Yana (2015-01-22). "Convergent evolution of sunbird pollination systems of Impatiens species in tropical Africa and hummingbird systems of the New World". Biological Journal of the Linnean Society 115 (1): 127–133. doi:10.1111/bij.12475. ISSN 0024-4066.

[:1-8] 8,0 ^8,1 McWhorter, Todd J.; Rader, Jonathan A.; Schondube, Jorge E.; Nicolson, Susan W.; Pinshow, Berry; Fleming, Patricia A.; Gutiérrez-Guerrero, Yocelyn T.; Martínez del Rio, Carlos (July 2021). "Sucrose digestion capacity in birds shows convergent coevolution with nectar composition across continents". iScience 24 (7). doi:10.1016/j.isci.2021.102717. ISSN 2589-0042. PMID 34235412. PMC 8246690. //www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=8246690.

[9] Karasov, W. H. (1992-09-01). "Tests of the adaptive modulation hypothesis for dietary control of intestinal nutrient transport" (en). American Journal of Physiology. Regulatory, Integrative and Comparative Physiology 263 (3): R496–R502. doi:10.1152/ajpregu.1992.263.3.R496. ISSN 0363-6119. PMID 1415633. https://www.physiology.org/doi/10.1152/ajpregu.1992.263.3.R496.

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