Lokacin Quaternary

A cikin bayanan da suka gabata mun bincika yadda yake aiki lokacin ilimin kasa kuma yayi bitar mahimman abubuwan da suka faru a zamanin Mesozoic y en el Preeambrian Aeon. Yau zamu koma zamanin Cenozoic wanda zamuyi nazarin abin da ke faruwa a ciki lokacin Quaternary. Labari ne game da lokacin ƙarshe na zamanin Cenozoic kuma wannan ya haɗa da zamani biyu na zamani "zamani", Pleistocene da Holocene.

Shin kana son sanin muhimman abubuwanda suka faru a wannan lokacin? Ci gaba da karatu domin zamu fada muku komai.

Zuwan kankara da mutum

Bayan wucewar miliyoyin shekaru, muna kusantar abin da ya kasance "yau". A cikin Quaternary, wanda fara miliyan 2,59 shekaru da suka gabata, shine lokacin da muke a yau. Quaternary ba kawai ya hada da Pleistocene da Holocene ba, amma don daidaito yayin yin bincike game da canje-canjen da suka faru a duniya, za a iya haɗawa da shekarun Gelasia. A wannan zamanin akwai canje-canje masu matukar mahimmanci a rayuwa a doron ƙasa, yanayi da tekuna saboda yanayin shekarun kankara.

Zamanin biyu na Quaternary sune Pleistocene da Holocene. Pleistocene shine mafi tsayi kuma ya haɗa da ƙarni da ƙarni na kankara. An san shi da Lokacin kankara. Zuwa wani sabon kwanan nan muna da Holocene, wanda aka ɗauka azaman ɓangaren bayan glacial kuma wannan shine abin da muke dashi a yau.

Lokacin magana game da Pleistocene, mutane da yawa suna magana akan "Shekarun mutum" tunda asalin Homo ya fara samuwa a wannan zamanin. Ya riga ya zama lokacin cikin Holocene, ɗan adam na iya haɓaka rayuwa mai tsari a cikin ƙungiyoyin zamantakewar jama'a wanda ake kira wayewa.

Halayen Pleistocene

Zamu fara da bayanin Quaternary tare da farkon sa. Shekaru miliyan 2,59 da suka gabata sun ba da farkon Pleistocene wanda ya ƙare shekaru 12.000 kawai da suka wuce. A wannan lokacin kankara ta yadu a cikin yanayin kankara har mamaye fiye da rubu'in ƙasa. Kankara ta isa yankunan da ba a taba kaiwa ba. Kuma shine lokacin da muke magana game da kankara ko zamanin kankara abin da ake tunani shi ne cewa duk duniya ta rufe kankara, gami da teku. Wannan ba haka bane. Kusan kashi 25% na duk duniyar da aka lulluɓe kankara abin al'ajabi ne.

Saboda yawan dusar kankara a duniya, matakin teku ya sauka zuwa mita 100 kuma rayuwa a doron kasa dole ne ta saba da sababbin yanayin muhalli ko kuma ta bace. A yankunan da babu kankara, kusan dukkanin flora da fauna sun kasance iri ɗaya ne a lokacin da ya gabata (Pliocene).

Akwai manyan tsarin glacial warwatse ko'ina cikin yankunan sanyi da kankara. Na farko shine kankara a cikin Scandinavia wanda ya faɗi kudu da gabas a duk arewacin Jamus da yammacin Rasha. Ya isa Tsibirin Birtaniyya, don haka zaku iya tunanin girman wannan dusar kankara.

A gefe guda kuma, mun sami wani babban tsarin glacial wanda yake ko'ina cikin yawancin Siberia. Wani tsarin glacial ya bazu daga Kanada zuwa Amurka. Duk waɗannan tsarukan kankara, bayan tasirin su da samuwar su, sun haifar da tsarin ƙanƙanin kankara wanda zamu iya lura dashi yau a duk waɗannan wuraren.

Glaciations, flora da fauna

Kamar yadda za'a iya hangowa, yankin Arctic da Antarctic suma an rufe su da kankara, kamar yadda yawancin duwatsu suke a duniya. Matsayin dusar kankara ya sauka zuwa matakan da ba a taɓa lura da su ba a yau. Kamar yadda na ambata a baya, ana iya ganin duk ayyukan da dusar kankara da narkar da su a gaba har yau a sassa da yawa na duniya.

Ba wai kawai akwai glaciation daya a lokacin Pleistocene ba, amma akwai shida. Tsakanin kowane ɗayansu akwai lokutan da yanayi ya ɗan fi ɗumi da ƙanƙara ta sake ja da baya. A yanzu haka, ana ɗauka cewa muna cikin ɗayan waɗannan lokutan hutu na hutu.

Dangane da flora da fauna da suka dace da wuraren daskararru gaba daya, mun sami mammoths, reindeer, giant deer and polar bears. Ciyawar dake wannan yankin ta kunshi gabaɗaya da ledoji da mosses. Ya kasance kwatankwacin tundra na yanzu. A cikin matakan kabilanci, suna da yanayin zafi mai yawa da ƙasa da ƙanƙan da ke rufe kankara, zasu iya rayuwa dawakai, dabbobi masu manyan hauren giwa da karkanda.

Wasu speciesan wasu nau'in fauna sun dace da sauyin yanayi sosai don su daɗe da rayuwa. Muna magana ne game da bison, Elk, fox da wildcat. A cikin sassan Arewacin Amurka masu sanyi, nau'ikan halittu kamar su rakumi, yak, llama, tapir da doki. A lokacin da Pleistocene ya ƙare, yawancin dabbobi masu shayarwa irin su mastodon, sanannen damisa mai haƙori, da kuma babban barewa sun riga sun ɓace daga duniya baki ɗaya.

Juyin halittar mutum da Holocene

Yanzu muna magana game da juyin halittar mutum wanda muke dashi a cikin Paleolithic a cikin Pleistocene, inda Homo habilis fara tattarawa da farauta. Daga baya, Homo erectus sanya wasu ingantattun makamai da farauta cikin kungiyoyi. Homo Neanderthalensis jinsi ne da ya dace da sanyin da ya bayyana shekaru 230.000 da suka gabata.

Muna ci gaba da bayanin kwanan nan na Quaternary: Holocene. Shine inda muke a yau. Ya fara shekaru 12.000 da suka gabata kuma hanyar canjin canjin yanayin ya fara lokacin narkewa a duk duniya. Wannan narkewar ta haifar da hauhawar matakin teku da mita talatin.  An ce wannan zamanin na rikice-rikice na iya ƙarewa cikin sabon zamanin kankara.

A cikin wadannan shekaru 12.000, dadaddun abubuwa sun ci gaba kuma an kara hanzarta su cikin shekaru 100 da suka gabata ta gaban ɗan adam da ci gaban fasaha. A duniya an sami halaye 5 masu girma. Saboda wannan dalili, ana kiran kisan gillar da take yi a yau halaka ta shida.

Rayuwar makiyaya ta ɗan adam ta ƙare tare da haɓaka noma da kiwo. Haka kuma kamun kifi ya yiwa ci gaban ɗan adam falala. Aƙarshe, Holocene galibi ana yin karatunsa har zuwa ƙirƙirar rubutu, inda abin da muke kira Tarihi ya fara karatu.

Ina fatan wannan rubutun ya kara muku sani game da lokacin karshe na Duniya.