Sixth extinction

The Holocene extinction, otherwise referred to as the sixth extinction or Anthropocene extinction, is the ongoing extinction event of species during the present Holocene epoch, mainly due to human activity. The large number of extinctions spans numerous families of plants and animals, including mammals, birds, amphibians, reptiles and arthropods. With widespread degradation of highly biodiverse habitats such as coral reefs and rainforest, as well as other areas, the vast majority of these extinctions is thought to be undocumented. The current rate of extinction of species is estimated at 100 to 1,000 times higher than natural background rates.

The Holocene extinction includes the disappearance of large land animals known as megafauna, starting at the end of the last Ice Age. Megafauna outside of the African continent, which did not evolve alongside humans, proved highly sensitive to the introduction of new predation, and many died out shortly after early humans began spreading and hunting across the Earth (additionally, many African species have also gone extinct in the Holocene). These extinctions, occurring near the –Holocene boundary, are sometimes referred to as the Quaternary extinction event.

The arrival of humans on different continents coincides with megafaunal extinction. The most popular theory is that human overhunting of species added to existing stress conditions. Although there is debate regarding how much human predation affected their decline, certain population declines have been directly correlated with human activity, such as the extinction events of New Zealand and Hawaii. Aside from humans, climate change may have been a driving factor in the megafaunal extinctions, especially at the end of the Quaternary.

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