Oceanography Test Questions – Flashcards
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sun
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gravity concentrates material at the center of a cloud
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eddies
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proplanets form from smaller concentrations of matter
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protoearth
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-larger than Earth today -homogeneous composition -bombarded by meteorites: moon formed from collision with large asteroid
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outgassing
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occurred during density stratification (origin of earth's atmosphere)
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What is the difference between a sea and an ocean?
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seas are smaller in are. seas are shallower in average depth. seas are partly enclosed by land. seas have a salinity that is different from the main oceans. (answer is all of the above)
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which is not true about the earth after its formation?
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the atmosphere was composed mostly of oxygen
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why does the earth have a nickel-iron core at its center, surrounded by silicate mantle?
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because it is more massive, the core material sank to the center of the Earth
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why is the continental crust higher than ocean crust?
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continental crust is thicker and less dense than ocean crust so it floats higher to the mantle
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continental and ocean crusts have different levels because oceanic crust is denser, assuming no difference in structure what would happen if the two types of crust were made of the same material?
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there would still be a difference because continental crust is thicker than ocean crust but the heights would be nearly the same
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what invention made accurate open ocean navigation possible by determining longitude?
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Chronometer
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Charles Darwin considered a career as a minister what would have happened to the theory of evolution had he not become a scientist instead?
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somebody else would have proposed the same idea about the same time.
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radio isotopes of potassium decay to agron. if a rock sample begins with 12 billion K40 atoms. What will the quantities of K40 and AR40 be after 1 half-life and 2 Half lives?
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9 billion K40 Atoms and 3 Billion Ar40 atoms
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Which of the following is not true about the oxygen on earth?
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It is essential for anaerobic bacteria's survival
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What is a scientific theory?
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An explanation for a natural phenomenon that is supported by many observations and widely accepted
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Which of the following would isostatic adjustment apply to?
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the floating of the lithosphere upon denser mantle beneath
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How did Earth's atmosphere form and progress throughout geologic time?
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1. outgassing of earth 2. photosynthesis leads to an oxygen environment
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How do the oceans form on the Earth?
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Condensation resulting from outgassing of early earth starts precipitation resulting in a relentless rain. Acidic rain fosters dissolution of mineral from rock to provide salinity.
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Stanley Miller's experiment using primordial gases and a primordial ocean proved what concepts?
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Given the right inorganic molecules, energy, and time, organic molecules like amino acids can form in the primordial oceans.
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Heterotrophs and autotrophs are linked on earth by the processes of cellular respiration and photosynthesis, respectively. Why is this?
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The end products of photosynthesis are the starting materials for respiration and vice versa.
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Alfred Wegener's theory of continental drift seems so reasonable today. Why was it rejected during the early 20th century?
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His jigsaw puzzle fit of the continental land mass showed large gaps. -He could not provide a driving mechanism for the continents that could plow through the ocean basins. -His mountain formation concepts were not adequate. -The best evidence would not be available until sea floor dating and magnetic reversal data. ALL OF THE ABOVE is the answer.
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Why are earthquakes mainly found at the edges of plates?
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Breakage and deformation of the lithosphere are focused at plate edges.
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What happens when plate tectonics causes two continents to collide at a convergent plate boundary?
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Neither continent will subduct, so they crumple and form mountain ranges.
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How does ocean basin form?
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Convection cells in the asthenosphere pull the sea floor apart, and the spreading creates ocean lithosphere in the gap left between the pieces.
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What is the difference between an atoll and a tablemount (guyot)?
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An atoll top is at sea level, but a tablemount top is below sea level.
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Transform plate boundaries are parallel to the relative motion between two plates. What would happen if the direction of plate motion changed?
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The transform boundary would turn into another type of boundary, either convergent or divergent depending on the direction.
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You are exploring an ocean basin and trying to determine whether it formed by sea floor spreading. Which of the following evidence would you NOT expect to find in an actively spreading ocean?
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Dredging of the mid-ocean ridge would yield granite.
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Where do most of the largest earthquakes occur?
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Convergent Plate Boundaries
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The alternating reversals of Earth's magnetic field throughout history have been recorded in sea floor rocks in a particular pattern and chronology. How does this support plate tectonics?
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The pattern of alternating reversals indicates sea floor spreading and, as a result, continental drift.
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Why are oceanic ridges different from oceanic rises?
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-Oceanic rises spread quickly and produce vast amounts of rock while oceanic ridges spread slowly and accumulate steeply.
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In relation to plate tectonics what is a major overall trend in earthquakes?
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Earthquakes occur at plate boundaries
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Why do the Hawaiian Islands form a chain in the Pacific Ocean's northern hemisphere?
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The Pacific Plate is moving slowing, but the hotspot remains in the same location.
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If you traveled to another earthlike planet with an ocean, how could you determine if tectonic plates and plate tectonic movement existed?
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Look for mountain ranges, oceanic ridges, oceanic trenches, and volcanoes. -From satellite imaging, observe a jigsaw fit of the continental edges. -Check seismic readings for earthquake activity. ALL OF THE ABOVE is the answer
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How does the Continental Arc System of mountain building, in which volcanic arc activity is apparent near a subduction zone, form?
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An oceanic plate collides with a continental plate.
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Paleomagnetism can be demonstrated in which of the following examples?
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The rock of Africa and South America have different magnetic polarities in rock of the same age.
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How are fringing reefs, barrier reefs, and atolls related in structure and chronology?
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Fringing reefs give rise to barrier reefs and then to atolls.
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Many of the unique properties of water, such as cohesion and its reputation as a universal solvent come from its atomic structure. What causes these properties?
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Water molecules are electrically polarized.
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What is the unit that is equivalent to raising the temperature of 1 gram of water by 1 degree centigrade?
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Calorie
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Why does ocean temperature change little from day to night?
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High heat capacity absorbs solar energy quickly and releases it slowly
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What does the principle of constant proportions tell us?
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No matter the salinity of the ocean water the ratio of the major dissolved ions remains the same
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Which of the following is not part of the hydrologic cycle?
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Water is added to the oceans and atmosphere by volcanic activity
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How does the latent heat of evaporation moderate climate?
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By absorbing energy on evaporation and releasing it on condensation it keeps water cool when the air is warm (only answer with evaporation in it)
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Hydrothermal vents are considered both a source and sink for ocean salts. How can one factor both add and take away salt?
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As water interacts with hot rock, some materials are dissolved whereas others are deposited.
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In the oceans all of the following processes decrease local salinity except for?
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Evaporation
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How does water have such strong surface tension?
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Hydrogen bonds form between adjacent molecules due to Water polarity thus giving it strong surface tension
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Why are lakes like the dead sea and great salt lake so buoyant?
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the water is hypersaline it has a high amount of dissolved solids making it extremely dense and buoyant
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Water in the ocean combines with carbon dioxide to form a weak acid called carbonic acid. But the oceans Ph is 8.1 on average wihcih is slightly basic. How is this so?
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There is a natural buffer system
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What happens when plate tectonics causes two continents to collide at convergent plate boundary?
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One continent is sub ducted into the mantle
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Transform plate boundaries are parallel to the relative motion between two plates. What would happen if the direction of plate motion changes?
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transform boundary would turn into another type of boundary, either convergent or divergent depending on the direction
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The general scientific consensus is that if levels of human cause emissions continue to increase what will happen?
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Overall earth will get warmer and the global distribution of climate patterns will change
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Why is it that a winter may be colder for one season if earth is said to be experiencing global warming?
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Because one of the documented changes that correlates to global warming is increased variation in temperature extremes. Also the climate can still be warming in the long term even if temperatures drop for one season.
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Of all the human caused gases which gas makes the greatest relative contribution to increasing the greenhouse effect?
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Carbon dioxide
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What is causing the hole in the ozone layer?
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CFCs
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The basic idea of global warming is sunlight enters the atmosphere from space and is then transformed to what type of energy that is trapped by CO2 in the atmosphere?
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Infrared radiations
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What is the record of CO2 in the atmosphere that has been collected from from volcano in Hawaii?
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The keeling curve
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Although the concentration of Co2 is measured in Hawaii has been going up steadily over the last 40 years it always goes down during the period of April to October why is this?
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Plants blooming in the spring
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How could climate change affect the drinking water supplies of people in Asia?
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Melting the Himalayan glaciers
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The ice core record from Antarctica goes back how many years?
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650,000
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What is the average depth of the ocean in meters?
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4000m
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Why is the east coast of the United States considered a passive margin it is far from any plate boundary and experiences?
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no major tectonic activity
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Why is the topography of the coastal continents similar to the bathymetry of the continental shelf?
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The shelf is continental crust
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What geologic feature would you expect to find at the downslope end of steep walled of submarine canyons?
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Multiple sorted layers of boulders, pebbles.
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What right angle features connect parallel segments of mid ocean ridges?
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Transform faults
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What causes most places on earth to have season?
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The spin axis is tilted 23.5 degrees to the plane of the orbit, causing solar radiation to vary in angle as earth revolves around the sun
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Why is ocean climate divided into latitude parallel zones that become progressively colder from equator to pole?
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The average solar radiation striking the surface declines from equator to poles
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What is the effect on surface winds of hearting air at the equator?
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Surface winds converge at the equator
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What causes ocean surface currents to form large gyres?
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wind blowing over the ocean, barriers formed by the continents
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What is the main cause of surface water sinking to cause the deep thermohaline ocean currents?
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-mixing of Density increase caused by cold in polar regions and Density increase caused by greater salinity
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In the atlantic north atlantic deep water sinks near Greenland and heads southalong the ocean bottom. Antarctic bottom water sinks off Antarctica and moves north along the ocean bottom. What happens when the two bodies of water meet?
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ABW stays on the bottom and NADW overrides it
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salinity developed from?
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dissolved rock elements
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outer shell of the lithosphere is made up of?
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continental and oceanic crusts
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vikings
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first people to cross the atlantic ocean
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longitude
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east or west separation from an arbitrary origin
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latitude
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north or south separation along the meridian compared to the equator
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Matthew Maury
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first full-time oceanography
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UNOLS
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University National Oceanographic Laboratory System
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Ptolemic theory
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earth is the center of a system and heavenly bodies move around us
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heliocentric theory
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earth and planets are part of a heavenly system orbiting the sun and the earth rotates on its axis as it orbits
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creationist theory
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all species were created at one time by a higher power
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darwinism
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all of the present day species have evolved from ancestors that lived in earlier times
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deluvian theory
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earlier catastrophe, like a great flood, caused the present arrangement
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Alfred Wegener
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first proposed Continental Drift and Pangaea
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