Holocene extinction From Wikipedia, the free encyclopedia Sixth extinction redirects here. For other uses, see Sixth extinction (disambiguation). The dodo, a flightless bird of Mauritius, became extinct during the mid-late seventeenth century after humans destroyed the forests where the birds made their homes and introduced mammals that ate their eggs. The quagga became extinct in 1883. The passenger pigeon became extinct in 1914. The Mexican grizzly bear became extinct in 1964. The Caribbean monk seal was officially declared extinct in 2008. The Holocene extinction, sometimes called the Sixth Extinction, is a name proposed to describe the extinction event of species that has occurred during the present Holocene epoch (since around 10,000 BCE) mainly due to human activity. The large number of extinctions span numerous families of plants and animals including mammals, birds, amphibians, reptiles and arthropods. Although 875 extinctions occurring between 1500 and 2009 have been documented by the International Union for Conservation of Nature and Natural Resources,[1] the vast majority are undocumented. According to the species-area theory and based on upper-bound estimating, the present rate of extinction may be up to 140,000 species per year.[2] The Holocene extinction includes the disappearance of large mammals known as megafauna, starting between 9,000 and 13,000 years ago, the end of the last Ice Age. This may have been due to the extinction of the mammoth that had maintained grasslands that became birch forests without the mammoths.[3] The new forest and the resulting forest fires may have induced climate change.[3] Such disappearances might be the result of the proliferation of modern humans which led to climate change. These extinctions, occurring near the Pleistocene–Holocene boundary, are sometimes referred to as the Quaternary extinction event. The Holocene extinction continues into the 21st century. There is no general agreement on whether to consider this as merely part of the Quaternary extinction event, or just a result of human caused changes.[3][4] Only during these most recent parts of the extinction have plants also suffered large losses. Overall, the Holocene extinction can be characterized by humanitys presence
Posted on: Tue, 16 Dec 2014 02:10:06 +0000
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