Fossils – Geology – Flashcards
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petrified fossil
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fossils in which minerals replace all or part of an organism
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mold
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a hollow area in sediment in the shape of an organism
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cast
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a solid copy of the shape of the organism
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carbon film
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an extremely thin coating of carbon on rock
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trace fossils
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evidence of the activities of ancient organisms
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preserved fossils
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remains of organisms in tar, amber, or ice
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How is mold related to a cast?
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Water deposits minerals in a mold which creates a cast.
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What can a paleontologist tell from fossil footprints of a dinosaur?
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It can show how they walked and the way they walked. It can show them the activities of a dinosaur.
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What can the fossil record reveal about the evolution of life on Earth?
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Millions of organisms have evolved, some have even gone extinct.
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evolution
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the process by which all the different kinds of living things have changed over long period of time
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sedimentary rock
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the type of rock that is made of hardened sediment
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extinct
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a type of organism that no longer exists and will never again live on Earth
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paleontologist
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scientist who studies fossils
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fossils
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preserved remains or traces of living things
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scientific theory
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a well tested concept that explains a wide range of observations
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fault
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a break in Earth's crust
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extrusion
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a hardened layer of lava on Earth's surface
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unconformity
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the surface where new rock layers meet a much older rock surface beneath them
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relative age
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the age of a rock compared with the age of other rocks
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law of superposition
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the way to determine relative ages of rocks
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intrusion
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a hardened layer of magma beneath Earth's surface
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absolute age
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the number of years since a rock has formed
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index fossil
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fossils used to help geologists match rock layers
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inference
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An educated guess and drawing conclusions from observations and data
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geologists
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people that study rocks
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What are 2 ways of determining relative age?
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law of superposition study extrusions and intrusions of igneous rock, faults and gaps in the geologic record
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pre-history
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story that began when humans were not alive
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What % of life is now extinct?
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99%
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What was the first creature that had eyes?
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trilibite
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What was the first creature that could breathe and have it's weight supported on land?
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fish
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What creature was able to survive both "Ages of Extinction" and is still thriving today?
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Cockroaches
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What was the size of the first horse?
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It was like the size of a dog.
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What is the oldest flower on Earth?
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Magmalia
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element
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a type of matter in which all the atoms making up the matter are the same
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True or false? All elements decay over time.
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False
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What occurs during radioactive decay?
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The atoms of one element break down to form atoms of another element.
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What rock does radioactive dating work well with?
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igneous
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How do scientists use the rate at which radioactive elements decay in rocks?
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The rocks change over time and form elements. They calculate the rock's age.
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What is true about radioactive decay? a) Over time, the amount of a radioactive element in igneous rock will increase. b) The rate of decay of each radioactive element is always changing. c) The rate of radioactive decay is an element's half-life. d) The half-life of a radioactive element is the time it takes for half of the radioactive atoms to decay.
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c and d
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True or false? Geologists use radioactive dating to find the absolute ages of rocks.
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True
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What 2 things must scientists measure to find the absolute age of a rock?
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The measure the amount of carbon 14 that is left in the organism's remains. They measure the radioactive element to the stable element.
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True or false? By comparing the amount of the radioactive element with the amount of the stable element, scientists can determine the absolute age of a rock.
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True
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What is the half life of Potassium 40?
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1.3 billion
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What does Potassium 40 decay to?
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stable argon 40
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What is Potassium 40 used for?
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the most ancient rocks
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What does Carbon 14 decay to?
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stable nitrogen 14
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What is Carbon 14 used for?
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material from plants and animals that are less 50,000 years old
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What is the half life of Carbon 14?
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5,730
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True or false? Carbon 14 can be used to date only organic materials that are less than about 50,000 years old.
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True
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True or false? Radioactive dating can be used only for igneous rocks, not sedimentary or metamorphic rocks.
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True, scientists date the igneous intrusions and extrusions near the sedimentary rock layers.
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What periods are the Paleozoic Era?
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Cambrian Ordovician Silurian Devonian Carboniferous Permian
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Cambrian
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1. Great explosion of invertebrate life occurs in seas 2. invertebrate with shells appear, including trilobites and mollusks
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Ordovician
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1. invertebrates dominate the oceans 2. early vertebrates, jaw-less fish become common
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Silurian
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1. fish with jaws develop 2. land plants appear 3. insects and spiders appears
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Devonian
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1. Age of Fishes begins as sharks and fish with scales and bony skeletons become common 2.Trilobites and corals flourish in the oceans 3. Lungfish develop 4. first amphibians reach land
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Carboniferous
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1. great swamp forests of huge, woody trees cover eastern North America and parts of Europe 2. first true reptiles appear 3. winged insects appear
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Permian
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1. reptiles become dominant on land 2. warm blooded reptiles appear 3. mass extinction of many marine invertebrates including trilobites
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When did Earth form?
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4.6 billion years ago
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What physical features formed during Earth's several hundred million years?
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volcanic landforms
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What do scientists think were the first organisms to evolve on Earth?
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Bacteria
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What were the periods of the Mesozoic Era?
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Triassic, Jurassic, Cretaceous
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Triassic
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1. some living things survived 2. the first dinosaurs appeared 3. Age of Reptiles started 4. mammals first appeared 5. mammals were very small, and now all mammals have evolved from them 6. trees form
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Jurassic
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1. dinosaurs become the dominant animals on land 2. the first birds evolved
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Cretaceous
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1. reptiles including dinosaurs dominated this era 2. flying reptiles became extinct 3. flowering plants sprouted 4. first snakes 5. mass extinction destroys everything
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What are the periods of the Cenozoic Era?
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Tertiary and Quaternary
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Tertiary
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1. Earth's climate was warm and mild 2. marine mammals evolved in the ocean 3. flowering plants 4. Age of mammals 5. first grass 6. horses, elephants, and bears appear 7. ancestors of humans
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Quaternary
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1. Mammals, flowering plants, and insects dominate 2. humans evolve in Africa 3. ice age wiped out animals
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True or False? During the Cambrian Period, all animals lived in the sea.
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True
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vertebrate
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an animal with a backbone
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mass extinction
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many types of living things become extinct at the same time
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What is one theory for the mass extinction at the end of the Paleozoic Era?
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Climate change resulting from continental drift
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What happened to Earth's continents during the Permian Period?
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Pangaea formed
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True or false? The formation of Pangaea caused the climate on Earth to change.
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True
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What type of living thing was most successful during the Mesozoic Era?
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reptiles
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mammal
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the first warmblooded wertebrates that fed their young with milk, appeared during the Triassic Period
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What is one hypothesis for the mass extinction at the end of the Cretaceous Period?
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An object from space struck Earth.
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Why didn't mammals evolve more during the Mesozoic Era?
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Dinosaurs dominated the Earth
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True or false? Whales and dolphins are all mammals that evolved in the oceans during the Tertiary period.
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True
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How did Earth's climate change in the Quaternary period?
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Earth's climate cooled which caused ice ages
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What is the order of the Era's from oldest to youngest?
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Precambrian Time Paleozoic Era Mesozoic Era Cenozoic Era
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Why is the geologic time scale used to show Earth's history?
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The time span of Earth's past is so great.
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What methods did geologists use when they first developed the geologic time scale?
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They studied rock layers and index fossils worldwide.
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How did geologists decide where one division of the geologic time scale?
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Major changes in life forms.
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The Geologic Time Scale
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the record of life forms and geologic events in Earth's history
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What was the Cambrian Explosion?
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When many life forms formed
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What are the 2 probable causes of two mass extinctions?
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Climate change and asteroids
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What created an opportunity for mammals in the Cenozoic Era?
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Extinction of dinosaurs
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What did mammals face in the Quaternary Period?
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Ice ages
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reptile
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animal with strong legs and eggs with thick shells
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amphibian
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animal that evolved from lung fish
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What is the longest time period?
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Precambrian
