It is estimated that over 99 percen

It is estimated that over 99 percent of all species that ever existed have become extinct. What causes extinction? When a species is no longer adapted to a change environment, it may perish. The exact causes of a species’ death vary from situation to situation. Rapid ecological change may render an environment hostile to a species. For example, temperatures may change and a species may not be adapt. Food resources may be affected by environmental changes, which will then cause problems for a species requiring these resources. Other species may become better adapted to an environment, resulting in competition and, ultimately, in the death of a species.

The fossil record reveals that extinction has occurred throughout the history of Earth. Recent analyses have also revealed that on some occasions many species became extinct at the same time - a mass extinction. One of the best - known examples of mass extinction occurred 65 million years ago with the demise of dinosaurs and many other forms of life. Perhaps the largest mass extinction was the one that occurred 225 million years ago, when approximately 95 percent of all species died. Mass extinctions can be caused by a relatively rapid change in the environment and can be worsened by the close interrelationship of many species. If, for example, something were to happen to destroy much of the plankton in the oceans, then the oxygen content of Earth would drop, affection even organisms not living in the oceans. Such a change would probably lead to a mass extinction.

One interesting, and controversial, finding is that extinctions during the past 250 million years have tended to be more intense every 26 million years. The periodic extinction might be due to intersection of the earth’s orbit with a cloud of comets, but this theory is purely speculative. Some researchers have also speculated that extinction may often be random. That is, certain species may be eliminated and others may survive for no particular reason. A species’ survival may have nothing to do with its ability or inability to adapt. If so, some of revolutionary history may reflect a sequence of essentially random events.

Kết quả (Hausa) 1:

An kiyasta cewa sama da 99 bisa dari na duka jinsin da ya taɓa kasancewa sun zama dadaddun. Abin da ya haddasa nau'i nau'i? A lõkacin da wata jinsin da aka ba saba da canji yanayi, kuma zai iya halaka. Ainihin Sanadin a jinsunan mutuwar bambanta daga halin da ake ciki to halin da ake ciki. M muhalli canjin iya sa wani yanayi maƙiya zuwa jinsunan. Alal misali, yanayin zafi na iya canja da wani nau'in iya ba za a daidaita. Abinci albarkatun iya shafi muhalli canje-canje, wanda zai sa to matsaloli ga wani jinsin bukata wadannan albarkatun. Wasu nau'in iya zama mafi alhẽri saba da wani yanayi, sakamakon shi da gasar, kyakkyawan, a cikin mutuwar wani nau'in. A daftarin burbushin halittu ya nuna cewa nau'i nau'i ya faru a ko'ina cikin tarihin duniya. 'Yan ƙididdiga sun kuma bayyana cewa, a wasu lokatai da dama jinsunan zama dadaddun a lokaci guda - a taro nau'i nau'i. Daya daga cikin mafi kyau - da aka sani misalai na taro nau'i nau'i faru 65 da miliyan da suka wuce tare da rasuwar dinosaur da kuma wasu masu siffofin rayuwa. Watakila mafi girma taro nau'i nau'i shi ne wanda ya faru 225 miliyan suka wuce, a lokacin da kimanin 95 bisa dari na duka jinsin mutu. Taro extinctions za a iya lalacewa ta hanyar wani in mun gwada da m canji a cikin yanayi da za a iya worsened da kusa interrelationship da dama jinsunan. Idan, misali, wani abu kasance faru da halaka da yawa daga cikin plankton a cikin teku, to, oxygen abun ciki na duniya, dã sauke, so ko da kwayoyin ba mai rai a cikin teku. Irin wannan canjin zai yiwuwa kai ga wani taro nau'i nau'i. Daya ban sha'awa, kuma mai kawo rigima, binciken shi ne cewa extinctions a lokacin da 250 shekaru miliyan sun kula zama mafi m kowace 26 shekaru miliyan. Da lokaci-lokaci nau'i nau'i zai yi saboda rarrabawa duniya ta madawwama biyu tare da gajimare na comets, amma wannan ka'idar ne zalla tabbas. Wasu masu bincike sun kuma cewar nau'i nau'i na iya zama sau da yawa bazuwar. Wato, wasu jinsunan iya shafe ta da kuma wasu na iya tsira ga wani dalili na musamman. A jinsunan 'rayuwa iya samun kõme ba su yi tare da ikon ko rashin daidaita. Idan haka ne, wasu daga neman sauyi tarihi yi tunãni a jerin gaske bazuwar abubuwan da suka faru.