Several mass extinctions have occurred during the Earth ’s history. The Cretaceous Tertiary Boundary (K-T) Extinction caused the loss of at least three-quarters of all species known at that time including the dinosaurs. The cause of this mass extinction is a controversial subject among scientists but the fossil evidence of it ’s occurrence is abundant. INTRODUCTION The K-T Extinction occurred 65 million years ago. Many species perished in that extinction. Today evidence for this extinction can be
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The Cause of the Mass Extinction in the Late Cretaceous Period Dinosaurs first appeared around 245 million years ago‚ and they lived for 180 million years. Then suddenly‚ 65 million years ago they went extinct. Not only did all the dinosaurs die out‚ but also up "to 75% of all marine genera were lost" ("mass extinction"). This leaves scientists wondering about what could have led to this mass extinction in the Cretaceous Period. They have collected evidence from fossils and earth’s geography‚ to
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decide which of three explanations for the extinction of the dinosaurs you like best. Write an explanation of why you like it. Sex: Testes function only in a narrow range of temperature. (Those of mammals hang externally in a scrotal sac because internal body temperatures are too high for their proper function.) A worldwide rise in temperature at the close of the Cretaceous period caused the testes of dinosaurs to stop functioning and led to their extinction by sterilization of males. Drugs: Angiosperms
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Bemaraha Woolly Lemur Avahi cleesei Description Named after the comedian John Cleese‚ the Bemaraha woolly lemur is a little known Madagascan primate first described in 2005. Like other woolly lemurs‚ this species has thick‚ tightly-curled‚ brown-grey fur‚ and a long tail that is often rolled up against the back. Pale fur on the small‚ rounded head extends from the forehead‚ down towards the nose‚ forming a distinctive triangular shape. The Bemaraha woolly lemur is different from related species
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The Extinction of Baiji The Baiji‚ also known as the Chinese River Dolphin‚ are part of the family Plantanistiade‚ the river dolphin family. They had exsited in the Yangtze River in China for thousand of years. Nevertheless‚ the Baiji was recently declared extinct. The baiji’s demise can be attributed to over fishing‚ its lethal environment and the Great Leap Forward in China. Excessive and illegal fishing was a great threat to the baiji’s way of life. Electric fishing and the fishing method
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GMO’s inside a lab and work to expel the uncontrolled production of GMOs‚ because of the fact that the genetically modified organisms can interact with the environment and cause the transfer of harmful genes which can lead to the elimination and extinction of all natural organisms. It may not be a well known fact but GMOs have greatly increased our quality of life. GMOs have mainly helped our agricultural industries by increasing the size and the quality
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BIODIVERSITY AND EXTINCTION Biodiversity is determined by the variety of species extant in a specific ecosystem; this includes both animals and plants. Biodiversity is what gives an ecosystem a continuing and symbiotic relationship between all the organic and inorganic elements; maintaining the proper balance of different gases such as nitrogen‚ oxygen‚ hydrogen‚ carbon dioxide and many other elements‚ which differ in composition depending on the type of environment (such as subterranean‚ aquatic
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According to “Why Bee Extinction Would Mean the End of Humanity” written by Ishan Daftardar‚ Not only would humans be affected but animals a well. Cattles depend on alfalfa and lupins‚ both of which depend on insect pollination. No bees‚ means no milk or meat. The extinction of bees would also affect our fuel and clothing. Canola‚ responsible for fuel and cooking oil‚ needs bee pollination. We need
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The Role of Extinction in Evolution In contrast to the opposite phenomenon‚ speciation. This is surprising in view of the special importance Darwin attached to extinction‚ and because the number of species extinctions in the history of life is almost the same as the number of originations; present-day biodiversity is the result of a trivial surplus of originations‚ cumulated over millions of years. For an evolutionary biologist to ignore extinction is probably as foolhardy as for a demographer
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ourselves. They are innocent sufferers in a hell of our making. (JEFFREY MOUSSAIEFF MASSON & SUSAN MCCARTHY‚ When Elephants Weep) Now a days is common to listen that more and more kind of animals are going to be part of a long list of species in extinction called “the red list”‚ When a animal is endangered it means that they are disappearing fast or have a very small population. Every day we can see in the media the great campaign that is carried out to preserve these animals‚ as for example: they
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