Scientists are debating whether Earth is now in the midst of a sixth mass extinction. Scientists believe that volcanic eruptions in India caused global warming that also may have contributed to the mass extinction. A large crater off of Mexico’s Yucatán Peninsula suggests that an asteroid most likely struck there. Dinosaurs met their end about 65 million years ago in another mass extinction at the end of the Cretaceous period. Those losses, however, also paved the way for dinosaurs to evolve into existence, as mass extinctions create a chance for new species to emerge. Most of the Earth’s species went extinct roughly 266 million to 252 million years ago in the Permian extinction. Six mass extinctionsįossils show that there have been five previous periods of history when an unusually high number of extinctions occurred in what are known as mass extinctions. That’s why National Geographic and photographer Joel Sartore are building a Photo Ark, documenting every species in captivity, including those at risk of extinction. Many of the species that keep our planet diverse and healthy are rapidly disappearing in the wild. Passenger pigeons, billions of which frequently blanketed North American skies when Europeans arrived on the continent, went extinct when the last one died at the Cincinnati Zoo in 1914. Even the rapid growth of the human population is causing extinction by ruining natural habitats.Īmong the most famous species driven to extinction by humans is the dodo, a bird that primarily lived in the island nation of Mauritius and was popularized by its appearance in Lewis Carroll’s book “Alice’s Adventures in Wonderland.” Dodos were first mentioned by Dutch sailors in the late 16th century and last seen in 1662 after having been hunted to extinction. Humans also cause other species to become extinct by hunting, overharvesting, introducing invasive species to the wild, polluting, and changing wetlands and forests to croplands and urban areas. Changes to habitats and poor reproductive trends are among the factors that can make a species’ death rate higher than its birth rate for long enough that eventually, none are left. A quarter of mammals is at risk of extinction, according to IUCN Red List estimates. The disappearance of species from Earth is ongoing, and rates have varied over time. One thing we do know: The western black rhinoceros, the Tasmanian tiger, and the woolly mammoth are among the creatures whose populations at one point dwindled to zero, and it’s possible that species extinction is happening a thousand times more quickly because of humans.Įxtinction happens when environmental factors or evolutionary problems cause a species to die out. The most recent estimate put that number at 2 billion, and that will most likely change at some point. The truth is, scientists don’t know how many species of plants, animals, fungi, and bacteria exist on Earth.
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