THE GEOLOGIC TIMESCALE Divisions of Geologic Time * Eras are subdivided into periods...periods are subdivided into epochs. * Geological time begins with Precambrian Time. Precambrian time covers approximately 88% of Earth’s history. FOUR Eras… * PRE-CAMBRIAN – 88% of earth’s history * Paleozoic (ancient life) * 544 million years ago…lasted 300 million yrs * Mesozoic (middle life) * 245 million years ago…lasted 180 million yrs * Cenozoic
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There are many theories on how dinosaurs became extinct but scientists have not yet found a proven reason why. About sixty-five million years ago Dinosauriformes‚ or as we call them Dinosaurs‚ walked and roamed planet Earth. These massive carnivores‚ herbivores‚ and omnivores lived many years on earth before humans appeared. There were several variations of dinosaurs such as land‚ sea‚ and air dinosaurs. For a millions of years the dinosaurs thrived in their environment. They had an abundant food
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Adaptive Radiation‚ Convergence and the Marsupials Abstract Metatheria (Marsupalia) originated upon Laurasia in the Cretaceous with the oldest fossilised remains having been dated to 125 Ma. The first period of metatherian diversification occurred in the late Cretaceous. The K-T mass extinction created an ecological void in which mammalian radiation occurred in the Palaeocene. With South America isolated from North America throughout the Tertiary‚ there was the second great period of metatherian
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have caused all of them to die-off. What caused the demise of the dinosaurs and 60% of life on Earth at the time? How did it affect life on Earth afterwards? Are all of the Dinosaurs dead? Will this happen to humans in the near future? The Cretaceous-Tertiary extinction event‚ or the K-T event‚ is the name given to the mass extinction of the dinosaurs and other species that took place about 65 million years ago. For many years‚ paleontologists believed this event was caused by climate and geological
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What Killed Dinosaurs: New Ideas About the Wipeout Volcanic eruptions may have been culling dinosaurs before an asteroid struck. An illustration of dinosaurs fleeing a meteorite impact. Illustration by Mark Garlick‚ Science Source Ker Than for National Geographic News Published February 12‚ 2013 New insights about the asteroid thought to have killed off the dinosaurs suggest it may have just been the final blow‚ and that the reptiles were already suffering from a finicky climate prompted
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Impacts from Space and Mass Extinction Events A. Understand the concept of a biosphere and Earth System Science and that the biosphere has evolved over time. -Mass extinction: a crisis that affects life right across the planet from the deepest oceans to the highest mountains -Biosphere: all life on Earth is a part of the biosphere‚ a thin layer of life that exists on the surface of the planet and that interacts with the hydrosphere (oceans‚ lakes‚ and rivers)‚ the atmosphere‚ and the lithosphere
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background extinctions‚ sometimes however extinction rates rise suddenly for a relatively short time and this is a mass extinction. Mass extinctions that have occurred through time. There have been a number of examples the most famous being the Cretaceous-Tertiary mass extinction or K-T extinction‚ this is because the dinosaurs became extinct during this particular mass extinction. This is also the most recent large scale mass extinction and has been relatively well documented in the rock strata
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Colegio Dr. Roque Diaz Tizol Yabucoa‚ P.R. The Mesozoic era Bilogy Class Mr. Kim 10th grade 1 /27/ 14 Introduction In this report I will be explaining a few facts about the Mesozoic era coming from the documentary “The day the Mesozoic Died”. This small film expresses how in many ways these creatures once inhabited our planet and disappeared completely in almost a blink of an eye. The Mesozoic Era could also be described
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Extinction Extinction is the termination of evolutionary lineage. The most common extinction event is the loss of a species. There are many reasons why a species might die out. Human intervention (either directly or indirectly) has become the leading cause of species extinction (possibly for the last fifteen thousand years). Species and Populations An important distinction must be made between true extinction and extirpation. Extirpation is the loss of a population‚ or loss of a species
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<b>Introduction</b><br>Think of a world which existed 290 million years ago. As you look out over the terane in front of you‚ you think that you are on an alien planet. You see volcanoes spewing ash and lava. Beside them is the ocean which is swarming with many different species of echinoderms‚ bryozoans and brachiopods. As you look down onto the sea floor you are amazed at the countless number of starfish and urchins. Some animals leave you can’t even describe and you have no idea even what phylum
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