Izityalo imithambo zingabokuqala ukubonakala. Nangona kungekho mahluko ungako njengokuba kukho ii-angiosperms, abalinganiswa bethu abaphambili bakwiqela labo bakwazileyo ukoyisa indawo apho kungekho sityalo seentyatyambo esikwaziyo ukusinda. Ngapha koko, eli hlathi, lihlathi leenyamakazi elifumaneka eYurophu, ligubungela ummandla omalunga ne-16.800.099 XNUMX yeekhilomitha ezizikwere.
Kulapho, ihlobo lifutshane kakhulu kwaye ubusika buyabanda kwaye bude. Qho ngonyaka imbonakalo yomhlaba igutyungelwa likhephu, kwaye iintyatyambo zenza konke okusemandleni ukuze ziye phambili, ukuya kwinqanaba lokuba ziyeke ukukhula de kubuye imozulu elungileyo. Kodwa yile nto ijimnosperms: abasindileyo bokwenyani. Yazi imbali yayo.
Zivela nini izityalo zejimnosperm?
IiGymnosperms zizityalo ezingaphambi kwembali, ethi baqala ukuvela kwabo malunga neminyaka engama-300 yezigidi eyadlulayo, ngexesha leMesozoic. Eyona nto inomdla kukuba kwiminyaka emalunga nezigidi ezingama-50 ibingabo kuphela eMhlabeni, ukusukela Iinkqubo, oko kukuthi, iintyatyambo, zavela malunga neminyaka engama-250 yezigidi eyadlulayo. Ke sinokuthatha ngokungakhathali ukuba ii-dinosaurs ezirhabaxa zikwazile ukungcamla ezo ntlobo zakudala.
Ngexesha lePermian, malunga nezigidi ezingama-300 zeminyaka eyadlulayo, kwabakho uthotho lweenguqu zemozulu kwiplanethi eyadala ukuba imeko yemozulu yome kwaye yome. Ngale nto, i-glaciation eyaqala ngexesha lokugqibela kweCarboniferous yaphela, apho uninzi lweentlobo zanyamalala njengoko zazingakwazi ukuziqhelanisa neemeko zokuphila ezintsha. Kodwa konke oku, nangona oko kwakuthetha ukuphela kwezityalo ezininzi, yayisisiqalo sejimnosperm ezininzi esizaziyo namhlanje.
Yintoni iijimnosperms?
Olona phawu luphambili lolu hlobo lwesityalo ziimbewu zayo: ezi zishiywa zingakhuselekanga, rhoqo, ukusukela kumzuzu wokuqala apho i-ovule yeentyatyambo ichunyiswa ide imbewu igqibe ukukhula. Ngapha koko, ixesha lokuvuthwa linokude kakhulu, ukuya kuthi ga kwiminyaka emithathu kwezinye iimeko.
Oku kuthetha ukuba kukho indidi encinci xa kuthelekiswa naleyo yee-angiosperms; inyaniso, kukho malunga ne-15 leentsapho zezityalo, ezibandakanya malunga ne-80 yezifo kunye ne-820 zizonke (Kukho malunga nama-257 amawaka eentlobo ze-angiosperms). Oko kukuthi, bambalwa, kodwa inyani kukuba bakwazile ukuhlala phantse kuyo yonke imimandla yehlabathi.
Ukwahlulahlula ii-gymnosperms
Iindidi ezine zibekiwe ezikwazileyo ukufikelela kwiintsuku zethu, kwaye zezi:
- ICycadidae: okanye ii-cycads. Kukholelwa ukuba imvelaphi yabo ibuyele kwiCarboniferous, kwaye zizityalo ezifanayo - azifani - njengemithi yesundu, enesiqu esithanda ukuya kwisebe kunye namagqabi aluhlaza kunye nofele. Njengemizekelo sine Icycas revoluta okanye al UDioon edule.
- Ginkgoidae: okwangoku kukho kuphela Ginkgo biloba, ongumthi onqabileyo wemfuza onxulumene neecycads (olunye ulwazi) kwasekuqaleni kwiPermian.
- Gnetidae: zinomdla wokuzivocavoca, kuba njengee-conifers azizikhuseli iimbewu zazo, kodwa zinezakhiwo ezifanayo neentyatyambo ze-angiosperms. Ummeli walo ophezulu ngu iWelwitschia mirabilis.
- IPinidae: okanye njengoko aziwa njalo: iiConifers. Yimithi okanye ityholwana eguqukileyo ukusukela kwiCarboniferous esezantsi, kwaye sinokuyifumana kumahlathi ashushu nakumahlathi ashinyeneyo. Kweli qela sinePinus, vula, Cupressus, kunye ITaxus, phakathi kwabanye.
Imizekelo yejimnosperms
Nangona sele sichazile ezimbalwa, siza kwazi ezinye zeendidi kunye neempawu zazo:
IAraucaria auracana
Umfanekiso -Wikimedia / MdE
La araucaria okanye pewén Sisityalo esihlala siluhlaza esidala kwiPehuén, eChile. Ikhula ukuya kwi-50 yeemitha ukuphakama, kwaye ivelise isiqu esithe nkqo ukuya kuthi ga kwiimitha ezi-3 ubukhulu. Yenza amasebe aliqela kwiimitha zomhlaba, ikhulisa amasebe anamagqabi afana nenaliti ukuya kwiisentimitha ezi-4 ubude. Ixhasa ukuya kuthi ga kwi-18ºC.
Icycas revoluta
Umfanekiso -Flickr / iincwadi zokupheka
Eyaziwa njenge-cica okanye umthi wesundu wobuxoki, sisihlahla esihlala sihlaza esihlala emazantsi eJapan. Inomboko omalunga neesentimitha ezingama-20 ukutyeba ukuya kuthi ga kwi-7 yeemitha ukuphakamaIsithsaba ngamagqabi aphinikiweyo malunga neesentimitha eziyi-150 ubude. Ivelisa inflorescence yabasetyhini kunye neyamadoda kwiindidi ezahlukeneyo, eyokuqala inkulu. Ixhasa ukuya kuthi ga kwi -7ºC.
Ginkgo biloba
I-ginkgo, ekwabizwa ngokuba ngumthi wamakhaka angamashumi amane, ngumthi onqabileyo okhoyo iminyaka engama-250 yezigidi. Kukholelwa ukuba yeyokuzalwa kwindawo ngoku eyi China, kwaye Sisityalo esifikelela kwiimitha ezingama-35. Umboko uthe nkqo, kwaye uvelisa isithsaba esenziwe ngephiramidi esenziwe ngamagqabi aluhlaza amile okwe fan, nangona ajika abe tyheli ekwindla ngaphambi kokuwa. Ivelisa iintyatyambo zabasetyhini nezamadoda kwiindidi ezahlukeneyo, kwaye iziqhamo ziyafana nedrupe, malunga neesentimitha ezi-2-3. Inqaba ukuya kuthi ga kwi -18ºC.
IPinus pinea
Umfanekiso -Wikimedia / GPodkolzin
El ipine yamatye sisityalo esihlala siluhlaza esidala kwingingqi yeMeditera. Ikhula ukuya kwi-50 yeemitha ukuphakama ngezihlandlo ezithile, kodwa into eqhelekileyo kukuba ayidluli kwiimitha ezingama-20. Umboko wayo uthanda ukuxhomekeka okanye ukujija kancinci kule minyaka idlulileyo. Isithsaba sijikeleze kwaye senziwe ngamagqabi e-acicular ukuya kwi-20 cm ubude. Uvelisa iikhowuni ngamantongomane ompayini. Inqaba ukuya kuthi ga kwi -12ºC.
iWelwitschia mirabilis
Umfanekiso - Wikimedia / Hans Hillewaert
La welwitschia Sisityalo esihlala sodwa kwintlango yaseNamib, eAfrika. Yeyona nto inomdla kakhulu kuba inamagqabi amabini kuphela anokuba malunga nemitha enye ubude. Xa ifikelela ebudaleni, ivelisa iintyatyambo ezizimazi okanye ezamadoda kwiindidi ezahlukeneyo. Ayikuxhasi ukubanda okanye iqabaka.
Siyathemba ukuba uyithandile yonke into esikuxelele yona malunga neejimnosperms.