<P> The Quaternary period saw the extinctions of numerous predominantly megafaunal species , which resulted in a collapse in faunal density and diversity , and the extinction of key ecological strata across the globe . The most prominent event in the Late Pleistocene is differentiated from previous Quaternary pulse extinctions by the widespread absence of ecological succession to replace these extinct species , and the regime shift of previously established faunal relationships and habitats as a consequence . The earliest casualties were incurred at 130,000 BCE ( the start of the Late Pleistocene ) , however the great majority of extinctions in Afro - Eurasia and the Americas occurred during the transition from the Pleistocene to the Holocene epoch ( 13,000 BCE to 8,000 BCE ) . However , this extinction wave did not stop at the end of the Pleistocene , but continued , especially on isolated islands , in human - caused extinctions , although there is debate as to whether these should be considered separate events or part of the same event . Among the main causes hypothesized by paleontologists are overkill by the widespread appearance of humans and natural climate change . A notable modern human presence first appeared during the Middle Pleistocene in Africa , and started to establish continuous , permanent populations in Eurasia and Australasia from 80,000 BCE , and the Americas from 22,000 BCE . A variant of the former possibility is the second - order predation hypothesis , which focuses more on the indirect damage caused by overcompetition with nonhuman predators . Recent studies have tended to favor the human - overkill theory . </P>
<P> The Quaternary period saw the extinctions of numerous predominantly megafaunal species , which resulted in a collapse in faunal density and diversity , and the extinction of key ecological strata across the globe . The most prominent event in the Late Pleistocene is differentiated from previous Quaternary pulse extinctions by the widespread absence of ecological succession to replace these extinct species , and the regime shift of previously established faunal relationships and habitats as a consequence . The earliest casualties were incurred at 130,000 BCE ( the start of the Late Pleistocene ) , however the great majority of extinctions in Afro - Eurasia and the Americas occurred during the transition from the Pleistocene to the Holocene epoch ( 13,000 BCE to 8,000 BCE ) . However , this extinction wave did not stop at the end of the Pleistocene , but continued , especially on isolated islands , in human - caused extinctions , although there is debate as to whether these should be considered separate events or part of the same event . Among the main causes hypothesized by paleontologists are overkill by the widespread appearance of humans and natural climate change . A notable modern human presence first appeared during the Middle Pleistocene in Africa , and started to establish continuous , permanent populations in Eurasia and Australasia from 80,000 BCE , and the Americas from 22,000 BCE . A variant of the former possibility is the second - order predation hypothesis , which focuses more on the indirect damage caused by overcompetition with nonhuman predators . Recent studies have tended to favor the human - overkill theory . </P>
when did the megafauna of north america go extinct
when did the megafauna of north america go extinct
The Quaternary period
The Quaternary period