Las dos grandes extinciones en masa conocidas de la Historia de la Tierra
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2022-07-12
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Jaén: Universidad de Jaén
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[ES] El concepto extinción hace referencia a aspectos negativos, la desaparación de un conjunto de individuos o de una proporción de biodiversidad, pero también tiene matices positivos como la aparición de nuevas especies después de producirse dicho proceso, en particular de forma masiva. A lo largo de la historia de la TIerra se han dado cinco grandes extinciones en masa, entre las que, destacan la del límite Pérmico-Triásico hace 251 Ma y la del límite Cretácico-Paleógeno ocurrida hace 66 Ma. Ninguna de ellas ha supuesto el fin de la biodiversidad, siempre ha sucedido un proceso evolutivo. En efecto, posteriormente a la extinción del Pérmico-Triásico, durante la cual desapareció aproximadamente el 96% de las especies marinas y el 70% de los vertebrados terrestres, surgen los primeros mamíferos y las gimnospermas abundan en el planeta. Nos preguntamos si actualmente nos encontramos ante una secta extinción masiva, ya que, según los estudios de varios especialistas en extinción de especies, la pérdida de muchas de éstas en los últimos tiempos ha sido más rápida de lo normal, siendo un tanto alarmante.
[EN] The concept of extinction refers to negative aspects, the disappearance of a group of individuals or a proportion of biodiversity, but it also has positive nuances such as the appearance of new species after the process has occurred, particularly in a massive way. Throughout the history of the Earth, there have been five major mass extinctions, including the Permian-Triassic boundary 251 Ma ago and the Cretaceous-Paleogene boundary 66 Ma ago. None of them has meant the end of biodiversity; there has always been an evolutionary process. Indeed, after the Permian-Triassic extinction, during which approximately 96% of marine species and 70% of terrestrial vertebrates disappeared, the first mammals appeared and gymnosperms abounded on the planet. We wonder if we are currently facing a mass extinction sect, since, according to studies by several specialists in species extinction, the loss of many species in recent times has been more rapid than normal, being somewhat alarming.
[EN] The concept of extinction refers to negative aspects, the disappearance of a group of individuals or a proportion of biodiversity, but it also has positive nuances such as the appearance of new species after the process has occurred, particularly in a massive way. Throughout the history of the Earth, there have been five major mass extinctions, including the Permian-Triassic boundary 251 Ma ago and the Cretaceous-Paleogene boundary 66 Ma ago. None of them has meant the end of biodiversity; there has always been an evolutionary process. Indeed, after the Permian-Triassic extinction, during which approximately 96% of marine species and 70% of terrestrial vertebrates disappeared, the first mammals appeared and gymnosperms abounded on the planet. We wonder if we are currently facing a mass extinction sect, since, according to studies by several specialists in species extinction, the loss of many species in recent times has been more rapid than normal, being somewhat alarming.