The mass extinction of dinosaurs is still a mystery today but their are many theories supporting how and why approximately 70% of all living species on earth suddenly became extinct including dinosaurs‚ 66 million years ago. The most common and realistic theory is the astroid impact theory when a astroid 6-15 km in diameter hit earth with the force of five billion atomic bombs. Another possible theory is climate change‚ the dinosaurs didn’t adapt fast enough to the climate when it was changing and
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A number of different theories have been assessed throughout the course of this research to attempt to reach a conclusion as to the reason behind the extinction of the Tyrannosaurus Rex. Although all arguments are credible‚ and supportive with educated information and data‚ the most conclusive theory of all is The Alvarez Asteroid Impact theory. Alvarez‚ a researcher at the University of California‚ discovered a pencil thin layer of Iridium around the rocks in Gubbio‚ Italy. (New Scientist‚
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Stephen Jay Gould‘s (2002) essay: Sex‚ Drugs‚ disasters‚ and the Extinction of Dinosaurs‚ investigates dinosaur extinction theories. According to Gould‚ scientific conclusions are the consequence; not the essence. Gould believes science’s main problem is the failure to separate fascinating claims from the scientific methods used‚ stating that “…science is‚ basically‚ a way of knowing” (pg.267). Gould examines three proposed ideas of dinosaur extinction. They are sex‚ drugs‚ and violence. Since
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Critically evaluate the consequences of anthropogenic disruption of trophic cascades in terrestrial ecosystems. Throughout the biological history of the earth various mass extinction events have occurred (2) in which worldwide biodiversity greatly declined. Currently‚ we are in the process of the sixth mass extinction (3) which unlike those before it‚ is characterised be the loss of large bodied species and more specifically the loss of apex consumers (4.5). Furthermore; current extinctions are
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INVESTIGATIONS INTO THE EVOLUTION OF AUSTRALIAN MAMMALS WITH A FOCUS ON MONOTREMATA Thesis submitted by ANNE MARIE MUSSER August 2005 For the Degree of Doctor of Philosophy in the School of Biological‚ Earth & Environmental Sciences University of New South Wales ABSTRACT This thesis began as an investigation into evolution of the platypus family (Ornithorhynchidae‚ Monotremata)‚ now known from both Australia and South America. The thesis broadened its scope with inclusion of non-ornithorhynchid
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confidently identified as an angiosperm‚ Archaefructusliaoningensis‚ is dated to about 125 millionyears or also known as Cretaceous period‚ whereas pollen considered to be of angiosperm origin takes the fossil record back to about 130 million years ago. But some scientist says that ginkgo is the first angiosperm on Earth.Based on them the angiosperms appears in the mid-Cretaceous approximately 100 million years ago. The Island genetics provides one proposed
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Campanian-Coniacian Sirte-Rachmat shale of upper Cretaceous era. This source rock contains minor amounts of carbonates (Tagrifet limestone). TOC of this sequence ranges from 0.5 to 8% (avg. of 1.5 to 4%). (1) * Other sources include: (1) * The Cenomanian-Turonian Etel Formation (evaporates‚ shales‚ and minor carbonates) (Upper Cretaceous). * The Nubian lacustrine to lagoonal shale in the Hameimat trough of the Nubian formation (Lower Cretaceous). TOC is approximately 3%. * Operation of
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is the period where the first fish‚ corals‚ shellfish‚ insects‚ spiders‚ and swamp forests appeared. Mesozoic era - (350 to 65 million years ago)We are most interested in this era. This era contained 3 periods: Triassic period‚ Jurassic period‚ Cretaceous period. Triassic period – 245 million years ago: All the continents were joined together in one huge landmass‚ aka Pangaea. Climate was hot and dry but with rain seasons. The first tree ferns and coniferous trees were starting to appear. The first
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scientific disciplines‚ including physical anthropology‚ primatology‚ archaeology‚ linguistics‚ evolutionary psychology‚ embryology and genetics.[1] Genetic studies show that primates diverged from other mammals about 85 million years ago in the Late Cretaceous period‚ and the earliest fossils appear in the Paleocene‚ around 55 million years ago.[2] The family Hominidae diverged from the Hylobatidae (Gibbon) family 15-20 million years ago‚ and around 14 million years ago‚ the Ponginae (orangutans)‚ diverged
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extinct. The Cretaceous-Tertiary ExtinctionAlmost all the large vertebrates on Earth‚ on land‚ at sea‚ and in the air (all dinosaurs‚ plesiosaurs‚ mosasaurs‚ and pterosaurs) suddenly became extinct about 65 Ma‚ at the end of the Cretaceous Period. At the same time‚ most plankton and many tropical invertebrates‚ especially reef-dwellers‚ became extinct‚ and many land plants were severely affected. This extinction event marks a major boundary in Earth’s history‚ the K-T or Cretaceous-Tertiary boundary
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