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TOPIC: Extinction


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RE: Extinction
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First the bad news - scientists are now 99 per cent certain mass extinction events on Earth are as regular as clockwork.
The good news? There's still 16 million years to go until the next one.
That's the finding from scientists from the University of Kansas and the Smithsonian Institute in the US, where they've mapped out all Earth's extinction events from the past 600 million years.

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Pinguinus impennis
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The Great Auk, Pinguinus impennis, formerly of the genus Alca, was a large, flightless alcid that became extinct in the mid-19th century.
The last pair of Great Auks were killed on the 3rd July 1844 on Eldey, Iceland.

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Dusky Seaside Sparrow

The Dusky Seaside Sparrow, Ammodramus maritimus nigrescens, was a non-migratory subspecies  of the Seaside Sparrow, found in Southern Florida in the natural salt marshes of Merritt Island and along the St. Johns River. The last one died on June 17, 1987  and the species was officially declared extinct in December 1990.
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Alaotra grebe
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A lake bird found only in parts of Madagascar, but not seen in more than 25 years, has been declared extinct - with its passing blamed on the introduction of a carnivorous fish.
The Alaotra grebe (Tachybaptus rufolavatus) lived in a tiny area to the east of the Indian Ocean island.

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RE: Extinction
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500 species of plants and animal vanish because of humans

Nearly 500 species of plants and animals have disappeared in England in the past 200 years, according to the first comprehensive audit of native wildlife.
The disappearances, which have been largely attributed to human activities, include four species that did not exist anywhere else. The great auk, a flightless seabird similar to a penguin, Ivells sea anemone, Mitten's beardless-moss and York groundsel, a weed, have all become extinct since 1800.

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Ancient clams discovered by College of Wooster geologist reveal how Earth rebounded from mass extinction

The rise of new clam types like those whose fossilised remains Wilson plucked from an Israeli hillside was part of a dramatic makeover of the world's oceans. As the planet rebounded from catastrophe, primitive marine animals gave way to the modern forms we recognise today.
The clams Wilson found were a sign of Earth's ongoing rejuvenation. They lived side by side in large mud mounds with other organisms - not as complex a community as the reefs that would come back later, but clearly an improvement in diversity.

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Out of sight, species quickly become out of mind

Once species disappear from the face of the Earth, they are quickly forgotten, says Samuel Turvey. In this week's Green Room, he warns that extinctions must be treated as a warning that human activities, such as overhunting and agriculture, are making the planet a poorer place to live.
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Australian megafauna
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Early humans caused extinction of Australia's giant animals

The mass extinction of Australias giant animals, such as huge kangaroos and rhinoceros-sized wombats, might have been more rapid than previously thought, according to new research from the University of Bristol. This suggests humans could have been responsible for wiping out the countrys megafauna between 50,000 and 40,000 years ago.
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New evidence links humans to megafauna demise

A new scientific paper co-authored by a University of Adelaide researcher reports strong evidence that humans, not climate change, caused the demise of Australia's megafauna - giant marsupials, huge reptiles and flightless birds - at least 40,000 years ago.
In a paper published today in the international journal Science, two Australian scientists claim that improved dating methods show that humans and megafauna only co-existed for a relatively short time after people inhabited Australia, adding weight to the argument that hunting led to the extinction of large-bodied species.

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Palaeontologists Find Extinction Rates Higher in Open-Ocean Settings During Mass Extinctions
For many years, paleobiological researchers interested in the history of biodiversity have focused on charting the many ups (evolutionary radiations) and downs (mass extinctions) that punctuate the history of life. Because the preserved record of marine (sea-dwelling) animals is unusually extensive in comparison, say, to that of terrestrial animals such as dinosaurs, it's been easier to accurately calibrate the diversity and extinction records of marine organisms.

"Paleontologists now recognise that there were five particularly large, worldwide mass extinction events during the history of life, known among the cognoscenti as 'The Big Five'. Much ink in research journals has been spilled over the past few decades on papers investigating the causes of these events" - Arnie Miller, University of Cincinnati professor of palaeontology in the McMicken College of Arts & Sciences.

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