...had little change of taking over. Then, 65 million years ago, the dinosaurs disappeared from the world altogether. Did they meet a quick and catastrophic end, or did they fade away gradually? What happened 65 million years ago? In the search for answers to what killed the dinosaurs at the end of the Cretaceous Period in the Mesozoic Era, scientists have looked beyond fossils. Geological evidence also holds clues and has led to many hypotheses, working explanations, of how dinosaurs may have become extinct. The extinction mystery is far from a simple “whodunit.” The same piece of evidence is sometimes subject to multiple interpretations. And, as yet, there is no obvious answer, no piece of evidence that strongly supports only one hypothesis while showing that all others are incorrect. So what do we know about dinosaur extinction, and how do we know it. Evidence: Scientific evidence and observations are the building blocks of hypotheses. At first the same evidence and observations may support different hypotheses. As more evidence becomes available, some hypotheses are proven, others are disproved, and new ones are formed. Hypotheses: A dinosaur extinction hypothesis is a testable statement describing factors that may have played a part in the dinosaur’s extinction and how long the process may have taken. Evidence, observations, and experimentation can serve to support or disprove a hypothesis. Regardless of its acceptance...
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...• English/US • Answers • Store • Outreach • Media • Kids • Education • Donate • Answers in Genesis • Answers • Animals • Dinosaurs • Dinosaur Extinction • The Extinction of the Dinosaurs The Extinction of the Dinosaurs by Michael J. Oard on August 1, 1997 Share: • • • • Originally published in Journal of Creation 11, no 2 (August 1997): 137-154. Shop Now First published: TJ (now Journal of Creation) 11(2):137–154 August 1997 by Michael J. Oard Dinosaur extinction is still a major enigma of earth history. In this review article, extinctions in the geological record will be briefly mentioned. Many of the imaginative theories for the extinction of the dinosaurs will also be presented. Within the uniformitarian paradigm, the meteorite impact theory, once considered ‘outrageous’, now is the dominant theory. However, the volcanic theory is still believed by a majority of palaeontologists. Both theories have their strengths and weaknesses. The unscientific behaviour of those involved in the meteorite paradigm change will be briefly explored. Evidence that the dinosaurs died in a cataclysm of global proportions will be presented, such as the huge water-laid dinosaur graveyards found over the earth. Occasional monospecific bone-beds and the rarity of fossils of very young dinosaurs suggest a catastrophic death and burial. The billions of dinosaur tracks recently discovered provide testimony to unusual, stressful conditions. Nests, eggs, and babies...
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...Dinosaur extinction is still a major mystery of earth history. In this review article, extinctions in the geological record will be briefly mentioned. Many of the imaginative theories for the extinction of the dinosaurs will also be presented. Within the uniformitarian paradigm, the meteorite impact theory, once considered ‘outrageous’, now is the dominant theory. However, the volcanic theory is still believed by a majority of paleontologists. Both theories have their strengths and weaknesses. The unscientific behavior of those involved in the meteorite paradigm change will be briefly explored. Evidence that the dinosaurs died in a cataclysm of global proportions will be presented, such as the huge water-laid dinosaur graveyards found over the earth. Occasional nonspecific bone-beds and the rarity of fossils of very young dinosaurs suggest a catastrophic death and burial. The billions of dinosaur tracks recently discovered provide testimony to unusual, stressful conditions. Nests, eggs, and babies are a challenge to a Flood model, but there are enough unknowns associated with the data that solid conclusions are difficult to draw. The part that impacts and volcanism play in a Flood paradigm will be briefly discussed. The question of whether the K/T boundary and the extinction of the dinosaurs should be considered a synchronous event within the Flood will be considered. Introduction Dinosaurs bring wonder to children and adults alike. That such great beasts once roamed the earth...
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...pieces, with one large piece detonating about 34 km above the surface, and a second, much larger piece detonating at an altitude of approximately 21 km” (Tagliaferri, 1998). Scientists were lucky to record this data via satellite to study the force an asteroid can have when impacting firsthand. There is evidence of asteroid impacts covering the surface of the earth and other surrounding planets in space. There are also many theories involving asteroid impacts causing mass extinctions on Earth, the most common being the extinction of the dinosaurs 65 million years ago (deGrasse Tyson, 2005). Most of the impact evidence shows that the earth has been attacked by these asteroids since its formation billions of years ago. Evidence all around us tells us that the Earth will be struck, and another major asteroid impact will occur. The most common and highly argued impact event is the one that may have wiped out the dinosaurs. This event in itself has many theories, but the one common element in most sound dinosaur extinction theories is that a major impact event occurred around the same time the dinosaurs stopped roaming the Earth. Most of the scientific community agrees that an asteroid impact did destroy the dinosaurs. Some scientists; however, claim that the dinosaurs were dying off well before the asteroid strike, due to climate changes, and that the impact only “finished them off” (Archibald, 2005). This very well could be...
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...The history of reptiles began when the first reptiles evolved from amphibians. Fossils of the first reptiles have been found in deposits from the early Carboniferous period (359-299 mya) and possessed characteristics that made them greatly resemble lizards; they were small in size, had four legs, were vertebrates, and possessed teeth that classified them as insectivores. These reptiles flourished due to the sheer amount of insects available around them, and by the end of the Permian period (299-251 mya) they had become the dominant land vertebrates. The Permian Period ended with the formation of Pangaea. Reptiles were successful in the interior of Pangaea because of the arid climate that they were adapted to; however, the end of the Permian...
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...generation regards the possibility of a forthcoming, human-induced mass extinction event and what it’s effects would be upon the evolution rate of species. In the search for understanding this possibility and its effects, scientists must look to the past where it is widely accepted that there have been 5 previous periods of mass extinction. The term ‘mass extinction event’ is defined as any period when abnormally large numbers of species die out simultaneously or within a limited time frame. Such occurrences have been observed at 5 places in history- the Ordovician-Silurian, Late Devonian, Permian, Triassic Jurassic and Cretaceous periods. What was the cause of these extinction periods? Well... no one can say for sure. Although there are a number of plausible hypotheses, the sheer amount of time and space between today and the events in question makes it very difficult to place a theory as anything more than conjecture. In saying this, it is known that these cataclysms were random occurrences and not caused by the actions of any one single species. The extinction of species is not normally considered an important element of Neodarwinian theory, in contrast to the opposite phenomenon, speciation. In the wake of mass extinction periods, the fossil records provide an accurate and reliable source of information invaluable to the study of evolution. Today, there is evidence mounting to suggest that the sixth mass extinction may be beginning- but the apocalypse this time is us. Human activities...
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...period the Earth saw the disappearance of seed-fern floras but the gymnosperms and true ferns were thriving"(Brannan 2012). Early Jurassic- The Liassic Epoch (176 to 200 mya) • Brought much warmer/wetter rainforest climate • Marine reptiles evolved such as, Ichthyosaurus, Temnodontosaurus, Euycleidus. • Terrestrial animals made an appearance such as the Stegosaurs, Tetanurae, Berberosaurus, Heterdonosaurids. In the Early Jurassic, the Colorado Plateau region again became arid and the eolian sandstones record zonal as well as monsoonal circulation (Parrish 1993). Following the dramatic decline, ichthyosaur diversity increased again to reach pre-extinction levels in the Early Jurassic, after which the group dwindled in diversity through the Middle and Late Jurassic and much of the Cretaceous until it disappeared at the end of the Cenomanian, 100 Ma, after 150 Myr of significant ecological dominance(Thorne, Ruta, Benton 2011). Berberosaurus is the oldest known abelisauroid, and it represents a considerable temporal...
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...passage and answer questions about it. In a real test, you would have 20 minutes to read the passage and answer the questions. Candidates with disabilities may request a time extension. Meteorite Impact and Dinosaur Extinction There is increasing evidence that the impacts of meteorites have had important effects on Earth, particularly in the field of biological evolution. Such impacts continue to pose a natural hazard to life on Earth. Twice in the twentieth century, large meteorite objects are known to have collided with Earth. 5 If an impact is large enough, it can disturb the environment of the entire Earth and cause an ecological catastrophe. The best-documented such impact took place 65 million years ago at the end of the Cretaceous period of geological history. This break in Earth’s history is marked by a mass extinction, when as many as half the species on the planet became extinct. While there are a dozen or more mass extinctions in the geological record, the Cretaceous mass extinction has always intrigued paleontologists because it marks the end of the age of the dinosaurs. For tens of millions of years, those great creatures had flourished. Then, suddenly, they disappeared. The body that impacted Earth at the end of the Cretaceous period was a meteorite with a mass of more than a trillion tons and a diameter of at least 10 kilometers. Scientists first identified this impact in 1980 from the worldwide layer of sediment deposited from the dust cloud that enveloped the planet...
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...Have you ever noticed that all the continents have edges that seem to fit together like a puzzle piece? That’s because the world used to be one big landmass called Pangaea. Pangaea, by definition is the hypothetical landmass that existed when all continents were joined, from about 300 to 200 million years ago (dictionary.com). Pangaea is also sometimes referred to as the “supercontinent.” Pangaea actually means “All-Earth.” Since there was only one continent, there was only one ocean. This ocean was called Panthalassa. Panthalassa means “All sea.” It’s very similar to Pangaea’s actual meaning. Since the land was one mass, the currents would’ve been calm and slow. Pangaea had different stages and turned into new masses of land. There were...
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...passage and answer questions about it. In a real test, you would have 20 minutes to read the passage and answer the questions. Candidates with disabilities may request a time extension. Meteorite Impact and Dinosaur Extinction There is increasing evidence that the impacts of meteorites have had important effects on Earth, particularly in the field of biological evolution. Such impacts continue to pose a natural hazard to life on Earth. Twice in the twentieth century, large meteorite objects are known to have collided with Earth. 5 If an impact is large enough, it can disturb the environment of the entire Earth and cause an ecological catastrophe. The best-documented such impact took place 65 million years ago at the end of the Cretaceous period of geological history. This break in Earth’s history is marked by a mass extinction, when as many as half the species on the planet became extinct. While there are a dozen or more mass extinctions in the geological record, the Cretaceous mass extinction has always intrigued paleontologists because it marks the end of the age of the dinosaurs. For tens of millions of years, those great creatures had flourished. Then, suddenly, they disappeared. The body that impacted Earth at the end of the Cretaceous period was a meteorite with a mass of more than a trillion tons and a diameter of at least 10 kilometers. Scientists first identified this impact in 1980 from the worldwide layer of sediment deposited from the dust cloud that enveloped the planet...
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...In the last five hundred and forty million years, the Earth has been the host to five mass extinctions (AccessScience Editors, 2014). Mass extinctions are defined as a global event during which at least fifty percent of all species die out in a geological period of time that is too short to allow adaptation (Mass Extinction, n.d.). It is important to note that species are always going extinct, just at a much slower rate than that of a mass extinction. This slow but constant extinction is known as background extinction, and is a normal part of the Earth’s cycle which has much less of an effect on biodiversity (Kohrs, 2018). Biodiversity is an invaluable resource to humans, which makes the recent changes in the Earth system alarming because many...
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...The extinction of dinosaurs can be seen as a lot of speculation. In “Sex, Drugs, Disasters, and the Extinction of Dinosaurs” Stephen Jay Gould explains how “science, is a fruitful mode of inquiry, not a list of enticing conclusions.” (Gould, 216). What makes something speculation and not science, which of the three theories are speculation, and what makes Gould question the theories. In “Sex, Drugs, Disasters, and the Extinction of Dinosaurs” Gould explains the differences of science and speculation. Science starts with a hypothesis and from there the scientist looks for evidence to back up his or her hypothesis. This evidence helps give the hypothesis validity and also allows other scientists to test said hypothesis. Gould states that “We can never be completely sure that a...
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...typically cause extinctions. One estimate is that less than 1% of the species that have existed on Earth are extant.[1] Biodiversity biodiversity is divided into three, phenotypic, genoti, environmental Ecological diversity refers to the sum of the different types of environment or Ecosystem present in a region or the habitat which is the sum total of the climate, vegetation and geography of a region. Ecosystem is a unit of the biosphere in which there is an interaction between the living and nonliving factors so as to maintain a continuous flow of energy. It is a structural and functional unit of a biosphere. There are several kinds of habitats or ecosystems around the world. The variety of diversity of species in an ecosystem is influenced by the ecosystem it self. Examples of ecosystems: Grass land, wet land, desert, aquatic ecosystem etc. Species diversity is the variety of different species in a given area. It is very difficult to estimate the different species in a given area. Most of the species are found near the equator and a few at the poles. Genetic Diversity may be defined as variation in genes with a particular species. It refers to the heritable variation. Sexual reproduction play an important role genetic diversity. A species having more genetic diversity can adapt better to the changed environmental conditions. Threats to biodiversity Extinction of Species Since the planet came into existence, it has been subjected to five mass extinctions, which...
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...Session 1.3: The Evolution of Cellular Life Exam review view in a separate window In this session we focus on the natural history of cells and the evolutionary timelines of their appearance. The modern phylogenetic classification of domains is used to categorize the different types of cells: bacteria, archea, and eukarya. The names of periods and organisms and certain dates are often helpful in remembering or understanding events that occur in the natural history of evolution. However, we do not expect you to know the names of all organisms mentioned nor all dates (you may find some of the sound attachments on complicated figures useful for review). Those names and dates mentioned below are the ones to key on. The focus in this session is macroevolution which looks broadly at the time lines and changes over long intervals of time. Remember that small changes over millions of years are the framework for evolving complexity from simplicity. Summary of concepts and idea An initial step in covering this material is an understanding of the different types of cells (prokaryotic, eukaryotic animal and plant), their differences, and their place in the phylogeny of life. 1. Information from pre-class reading, Bioflix animations and briefly summarized in class discusses the fundamental components of the prokaryotic and eukaryotic cells. You need to know the differences and understand the basic functions of the cellular components as cells as they are the fundamental...
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...include: the Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian. Early in the Paleozoic the continents were far apart but moving tectonic plates caused continents to move together into one large continent called Pangaea. Some of the significant geologic events that occurred during the Paleozoic era includes the evolution of a large number of animals, some of which are distant ancestors to modern organisms, between 530 and 520 million years ago. Also during this time period, there was an introduction to animals without backbones (invertebrates). Organisms such as corals, brachiopods, mollusks, and arthropods populated the early and middle parts of the Paleozoic era. A massive extinction event known as “The Great Dying” marked the end of the Paleozoic era. During this mass extinction, as many...
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