Flashcards and Answers – Geologic Time Scale
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Geologic Time Scale
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(GTS) is a system of chronological measurement that relates stratigraphy to time, and is used by geologists, paleontologists, and other earth scientists to describe the timing and relationships between events that have occurred throughout Earth's history
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EON
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an indefinite and very long period of time, often a period exaggerated for humorous or rhetorical effect
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ERA
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a long and distinct period of history with a particular feature or characteristic.
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PERIOD
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a rather large interval of time that is meaningful in the life of a person, in history, etc
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EPOCHS
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a period of time in history or a person's life, typically one marked by notable events or particular characteristics
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EVOLUTION
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the process by which different kinds of living organisms are thought to have developed and diversified from earlier forms during the history of the earth
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NATURAL SELECTION
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the process whereby organisms better adapted to their environment tend to survive and produce more offspring. The theory of its action was first fully expounded by Charles Darwin and is now believed to be the main process that brings about evolution.
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PRECAMBRIAN
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of, relating to, or denoting the earliest eon, preceding the Cambrian period and the Phanerozoic eon.
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SHIELD
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a broad piece of metal or another suitable material, held by straps or a handle attached on one side, used as a protection against blows or missiles.
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STROMATOLITE
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a calcareous mound built up of layers of lime-secreting cyanobacteria and trapped sediment, found in Precambrian rocks as the earliest known fossils, and still being formed in lagoons in Australasia
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TRILOBITE
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an extinct marine arthropod that occurred abundantly during the Paleozoic era, with a carapace over the forepart, and a segmented hind part divided longitudinally into three lobes.
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GRAPTOLITE
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an extinct marine invertebrate animal of the Paleozoic era, forming mainly planktonic colonies and believed to be related to the pterobranchs.
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EURYPTERID
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an extinct marine arthropod of a group occurring in the Paleozoic era. They are related to horseshoe crabs and resemble large scorpions with a terminal pair of paddle-shaped swimming appendages
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CRINOID
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an echinoderm of the class Crinoidea, which comprises the sea lilies and feather stars.
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FORAMINIFERA
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a single-celled planktonic animal with a perforated chalky shell through which slender protrusions of protoplasm extend. Most kinds are marine, and when they die, their shells form thick ocean-floor sediments.
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AMMONITES
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an ammonoid that belongs to the order Ammonitida, typically having elaborately frilled suture lines.
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PALEOZOIC ERA
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It is the longest of the Phanerozoic eras, and is subdivided into six geologic periods (from oldest to youngest): the Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian. The Paleozoic comes after the Neoproterozoic Era of the Proterozoic Eon, and is followed by the Mesozoic Era.
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MESOZOIC ERA
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Of, belonging to, or designating the era of geologic time that includes the Triassic, Jurassic, and Cretaceous periods and is characterized by the development of flying reptiles, birds, and flowering plants and by the appearance and extinction of dinosaurs. See Table at geologic time. n. The Mesozoic Era.
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Jurassic period
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The Jurassic constitutes the middle period of the Mesozoic Era, also known as the Age of Reptiles. The start of the period is marked by the major Triassic-Jurassic extinction event.
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Triassic period
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from 230 million to 190 million years ago; dinosaurs, marine reptiles; volcanic activity. Triassic. Age of Reptiles, Mesozoic, Mesozoic era - from 230 million to 63 million years ago.
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cretaceous period
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from 135 million to 63 million years ago; end of the age of reptiles; appearance of modern insects and flowering plants. Cretaceous. Age of Reptiles, Mesozoic, Mesozoic era - from 230 million to 63 million years ago.
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CENOZOIC ERA
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The Cenozoic Era is the current and most recent of the three Phanerozoic geological eras, following the Mesozoic Era and covering the period from 66 million years ago to the present.
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HOMINIDS
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a primate of a family ( Hominidae ) that includes humans and their fossil ancestors.
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Homo sapiens
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the modern species of humans, the only extant species of the primate family Hominidae.
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BIPEDAL
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(of an animal) using only two legs for walking.
