Earth Sciences 80A - 1995 Quiz #1

Instructions:

This is the first of 3 exams in this class. Each will count as 25% toward the total point accumulation possible for the course, and each will cover 1/3 of the lecture and reading material. The attendance and short paper in the discussion section will count for the other 25%. The quiz is to be completed in-class in 60 minutes or less. You cannot use any notes, and you are to do your own work (no discussion with classmates, no inspection of their answers). This exam has a total point value of 100.

Please write or print your short essay answers very clearly, so that your work can be easily read. Use appropriate size lettering so that you can fit your answer into the allowed space. Do not spill over onto the back of pages. Use reasonable grammar, but the substance of your answers is more important than style.

PRINT YOUR NAME CLEARLY in the indicated place at the top of each sheet of the exam (DO THIS NOW), because the graders will disassemble the exams.

When you have completed the quiz, take the entire exam to the front of the room and place it in the appropriate pile, and you are free to leave. Please try to minimize the disturbance of those around you as you depart. Good luck!

  1. Summarize your knowledge about the BIG BANG and expansion of the universe. When did the Big Bang occur; what are the lines of evidence supporting this hypothesis; what materials were produced during the process, etc.? (13 points)

     

  2. Consider the iron in your hemoglobin. Where in the universe did iron atoms originate? What processes and conditions were necessary, and what has happened to the place were the iron was formed? How did iron find its way to Earth? (13 points)

     

  3. Speculate, as we did in class, on how different the Earth system would be if the Mars-sized body which collided with it to produce the Moon had actually missed the Earth. List at least 3 major things that would be different. (10 points)

     

  4. In the left column there is a list of terms and names, each of which is associated with a concept in the column on the right (in the context of this class). In the blank space next to the terms on the left, write the letter of the term in the right hand column with which it is mostly clearly associated. There is a single 'best' association between all of the terms from the lectures, but some of the terms on the right do have secondary relationships to those on the left and you will get credit for picking a secondary relationship. (12 points)

     

    Gradualism             __________          A) Primordial soup
       
       
    Tycho's Star           __________          B) Earth Chemical Differentiation
       
       
    Doppler Shift          __________          C) Punctuated Equilibrium
       
       
    Condensation Sequence  __________          D) White Dwarf
       
       
    Amino Acids            __________          E) Anoxic bacteria
       
       
    Crust,Mantle,Core      __________          F) Supernova
       
       
    Magnetic field         __________          G) Planetisimal bombardment
       
       
    Magma Ocean            __________          H) Charles Lyell
       
       
    Sun's Fate             __________          I) Big Bang
       
       
    Spectroscopy           __________          J) Inhomogeneous Accretion
       
       
    Ocean thermal vents    __________          K) Cosmic abundance
       
       
    Extinctions            __________          L) Geodynamo
       

     

  5. Geologists love puzzle solving. The sketch below represents a cross section observed in a rock exposure. Using the basic ideas of "original horizontality", and "superposition", and your common sense, list the order in which the 6 rock formations were deposited, from first to most recent. A dike is an intrusion of molten rock, which would not have been deposited horizontally, but must be deposited in pre-existing rock. (6 points)

     

    Oldest Rock   _______     ______     ______     _______     _______     ______  Youngest
       

     

  6. Summarize your knowledge of the Cretaceous-Tertiary Extinction event. What are two hypotheses for the cause of this event, and what evidence supports each hypothesis? Is this event unique? (13 points)

     

  7. List at least 4 'Cosmic Coincidences' that have made the Earth a hospitable environment for our life form, and explain their significance (8 points)

     

  8. Describe how a combination of basic geologic ideas about rock depostition, fossils, and radioactive dating have yielded the geologic time scale. Discuss both relative and absolute time. (13 points).

     

  9. For each of the following statements, circle the most appropriate response (12 points total)
    1. Which of the following terms is not associated with ideas about how the dinosaurs went extinct:?
      • a) Deccan Traps
      • b) Iridium
      • c) Magma Ocean
      • d) Nemesis
    2. Nucleosynthesis is the process by which atoms are split by fission to produce new atoms.
      • a) True
      • b) False
    3. Which of the following terms is least associated with the idea that the Earth's core is mainly molten iron alloy?
      • a) cosmic abundance
      • b) radioactivity
      • c) magnetic field
      • d) density structure
    4. If you are a advocate of Uniformitarianism you are most likely to believe in which?
      • a) punctuated equilibrium
      • b) gradualism
      • c) bolide impacts
      • d) creationism
    5. As a modern Neo-Catastrophist (a modern Earth Scientist), which of the following Lyell doctrines are you least skeptical of:
      • a) Uniformity of Rate
      • b) Uniformity of Process
      • c) Uniformity of Physical Law
    6. Once life got started on Earth it was probably totally wiped out many times.
      • a) True
      • b) False
    7. We think the Earth's core existed before the Moon was formed because the Moon is enriched in iron.
      • a) True
      • b) False
    8. If you look at the very oldest stars in the Universe that are about the size of our sun, you would expect their spectroscopic 'fingerprints' to mainly indicate the presence of Hydrogen and Helium.
      • a) True
      • b) False
    9. About every 26 million years there has been a major extinction event on the Earth.
      • a) True
      • b) False
    10. The relative abundance of refractory materials in the Earth is not expected to be the same as the relative abundance of refractory materials in the sun.
      • a) True
      • b) False
    11. A rock at the surface of the Earth is not representative of the bulk composition of the Earth because the Earth is a chemically differentiated planet.
      • a) True
      • b) False
    12. The Earth had to build up an oxygen atmosphere before life as we know it could begin.
      • a) True
      • b) False

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