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At the other end of the existence of species spectrum are extinctions. As near as scientists can estimate, only 1 in 1,000 species which have existed at some time on Planet Earth still exist today. This is 0.1%
of known species which exist today. The geologic record shows there have been five mass extinctions, the most recent being the K-T extinction 65 million years
ago at the end of the Cretaceous period.3.255 This extinction is popularized in the magazines and newspapers today as when the asteroid hit the Yucatan Peninsula and wiped out the non-avian dinosaurs and many other species.3.256, 3.257, 3.258
In the spirit of questioning, I have wondered if the meteor impact was the only cause for the dinosaur demise. Today, environmentalist tell us cattle, which of course includes Herefords, are one of the primary causes of global warming, because of the amount of methane that is a byproduct of digesting pasture grasses.3.259 Imagine how much more foraging a Brontosaurus had to do than a Hereford cow does. Now imagine the relative amount of flatulence, and just maybe the vegetarian
dinosaurs created their own global warming, which created the deserts, which destroyed the dinosaurs, and which are so artfully depicted in Walt Disney's animated movie Fantasia. Study of bubbles trapped in amber at the end of the Cretaceous System show oxygen quickly dropped from 35% to 28%. Time Magazine reported dinosaur demise was after a comet hit, there was a second jolt from volcanoes which may have closed the deal.3.260 More recent studies of the 125 mile diameter Chicxulab impact crater show the presence of carbonates and sulfate rocks. If these were vaporized by the asteroid impact it would have created sulfur and carbon dioxide.3.261 Then another study said the extinctions may be due to the release of methane from deep water frozen gas hydrates.3.262 I still like the methane from flatulence theory. And as interesting and as fun as these theories and speculations can be, they have virtually nothing to do with how you or I live our lives each day.
The fact extinctions have occurred in nature was first recognized in the 1800's. The Dodo, a meter-high (3 feet) flightless bird only found on islands in the Indian Ocean, is an often cited example of modern extinction. It became extinct in the mid 17th century.3.263 Scientist warn that we are currently in the early stages of a human caused mass extinction, which has been named the Holocene
extinction event. Biologist E.O. Wilson predicts that by 2028 AD 20% of all living populations will become extinct, and that by 2100 AD this will expand to 50% of all living populations on earth today.
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paradoxes