FDSCI 209 – Flashcards
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Which of the following observations about the fossil record occurs shortly after the Snowball Earth episode?
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Evidence of eukaryotic cells
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How did the Snowball Earth episodes set the stage for the development of multicellular life?
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It permanently increased the O2 content enough for multicellular life to thrive
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Describe the Keeling CO2 curve (Fig 27 of Goldilocks Planet). When did the Earth's atmosphere last have its current level of CO2?
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About 400,000 years ago- curve shows rise and fall of CO2 in the atmosphere
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Discuss how these human impacts might affect the Earth's habitability. Describe what you can do personally to be a better steward of the Earth and its resources.
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Reduce carbon footprint and water footprint
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Which statement best explains why theories are not just guesses or assumptions?
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Theories predict observations that we should be able to see if they are true, so we can test them
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According to LDS doctrine, what is Earth's age?
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The LDS church has no official doctrine on Earth's age
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According to scientists, Earth's age is approximately
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4.6 Billion Years Old
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Since all stars begin their lives with the same basic composition, what property most strongly determines what makes them different (in temperature, lifetime, etc)?
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Their mass
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Where were most of the heavy elements found inside your body (such as carbon and iron) made?
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In stars and from explosions generated by dying stars
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The astronomer Edwin Hubble discovered that virtually all galaxies are moving away from us and the further away they are, the faster they are moving. What is the best explanation of this observation?
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All of the material in the universe began at a central point and is expanding into preexisting space
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What does discovery of amino acids in meteorites and discovery of water and other molecules in interstellar space imply about the habitability of the universe?
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It implies that molecules critical to life can form by natural means in environments other than the Earth
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How do scientists think the Earth's atmosphere formed?
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Mostly from outgassing—volatiles incorporated in the Earth's interior were released during volcanic activity
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Which statement best describes how the Earth was formed (based on the scientific evidence we now possess)?
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Planets formed within a disk surrounding the infant Sun by small solid particles sticking together to form larger particles.
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How do scientists think the oceans formed?
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Volcanic activity outgassed water vapor (and other gases) that condensed into liquid and rained onto the surface
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Which statement below best describes the greenhouse effect?
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The Sun's visible light warms the ground, which radiates energy in the infrared. Gases such as CO2 and H2O absorb this energy.
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Which statement best describes how the Earth's carbon cycle contributes to making the Earth a habitable planet over long time periods?
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The amount of CO2 in the atmosphere changes in response to several of Earth's feedback cycles, including weathering of rock, volcanoes, the influence of life, carbon burial in the oceans, cloud formation, etc.
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Which statement below describes Earth's water cycle's most important contribution to making the Earth habitable (not the role water plays in life's processes)?- no sure
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If Earth's temperature increases, water vapor production increases, increasing precipitation. More precipitation = more CO2 is washed out of the atmosphere and more erosion, causing CO2 burial and cooling.
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Which statement below best describes plate tectonics role in making the Earth a habitable planet?
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It plays a critical role in regulating the Earth's climate
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Which statement best describes one of plate tectonics' role in the Earth's carbon cycle?
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Volcanoes dump CO2 back into the atmosphere
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Which of the following statements best describes why the Earth experiences seasons?
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Earth is tilted on its axis compared to its orbital plane around the Sun. The Northern hemisphere receives more energy from the Sun during July than during January.
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Which statement best describes the "oxygen revolution"?- not sure
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A short geological period (<3 million years) when free oxygen in Earth's atmosphere built up from almost nothing to nearly its present level
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Which statement best describes the impact mass extinctions have had on the history of life on Earth?
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Mass extinctions greatly affect the course of life's development on Earth; only survivors of a mass extinction can reproduce
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List the 7 "core truths" that Hazen states in his introduction
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1. Earth is made up of recycled and recycling atoms. 2. Earth is immensely old when compared to human time frames. 3. Earth is three-dimensional, and most action is hidden from view. 4. Rocks are the record keepers of Earth 5. Earth systems- rocks, oceans, atmosphere and life- are complexly interconnected 6. Earth history encompasses long periods of stasis punctuated by sometimes sudden, irreversible events 7. Life has changed and continues to change Earth's surface
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Discuss why scientists believe the universe and Earth are ancient—billions of earth years old.
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Geological phenomena that produce annual layering of material Ice core drilling, ice forms layer after layer, year after year
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Discuss the three theories about how the Moon formed before the Apollo astronauts landed on the Moon in 1969. How well did these theories explain the observations from the Moon rocks?
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Coaccretion- Earth and Moon made of same planetesimals- ought to have same iron content/non-volatile proportion, same O isotopes Fission- core formed, giving Earth enough spin to toss off a piece- ought to have same composition, same O isotopes, lack iron Capture- Moon have any composition- why O isotopes the same but not the rest of the composition
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Describe the capture hypothesis of the Moon's origin
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The Earth's gravity caused a large asteroid to begin orbiting around it.
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What does the coaccretion hypothesis predict about the density of the Moon?- not sure- ask
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The Moon's density should be the same as the Earth's uncompressed density.
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Which of the following statements best explains how the Moon's composition compares to Earth's?
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The Moon's composition is enriched in refractory elements and depleted in volatile elements-the Moon is missing iron.
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How does the giant impact hypothesis explain why the Moon's density is so low? - not sure
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The projectile's core merged with the Earth's core—the ejected material was made from Earth and projectile mantle
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Which list below are the 6 most abundant elements in the Earth?
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Oxygen, Silicon, Iron, Magnesium, Calcium, Aluminum
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Why is this list different than the 6 most abundant elements in the Sun?- not sure
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Earth was made of "dust" from the inner Solar System. This dust was made of rock and metals, so it had very little gaseous materials like hydrogen, helium, carbon, and nitrogen
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Why does partial melting lead to the creation of rocks that are different in composition than their parent rock?
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Different minerals melt at different temperatures
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What is basalt?
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basalt is an igneous rock produced when 2-3% of mantle rock melts and the melt moves to the Earth's surface
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Describe how granitic crust formed from the Earth's early basaltic crust
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Same idea as forming basalt from mantle rock—partial melting of basalt-type rock
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Which statement best describes scientist's current thinking about how the Earth's atmosphere formed?
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Mostly from outgassing—volatiles incorporated in the Earth's interior were released during volcanic activity
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Which of the following properties does water possess because it is a polar molecule
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Ice is less dense than liquid
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When did oceans form on Earth, according to the evidence from the Jack Hills zircons?
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Within the 100-200 MY after the giant impact
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How do scientists think the bulk of Earth's oceans formed?
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Volcanic activity outgassed water vapor (and other gases) that condensed into liquid and rained onto the surface
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Why does the granitic continental crust rise above the ocean crust to create dry land?
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It is less dense than the mantle and ocean crust, so it floats on top of the mantle
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How did the granitic continental crust form from Earth's original basaltic crust?
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Partial melting of the base of the original basaltic crust
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At which type of plate boundary do mid-ocean ridges occur?
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Diverging
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Ocean trenches occur at which type of plate boundary?
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Converging
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What are the two functions of proteins in cells?
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Create structures and act as enzymes (organic chemical catalysts)
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Which type of molecule listed below carry genetic information?
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Nucleic Acids
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What is significant about the handedness of amino acids?
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Non-life processes create a roughly 50:50 mixture of amino acids; life uses only left-handed amino acids
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How do scientists usually interpret the fact you answered in question 3 about the handedness of amino acids?
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Life had a common origin
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What is the "Great Oxygenation Event"?
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A short geological period (<3 million years) when free oxygen in Earth's atmosphere built up from almost nothing to nearly its present level
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Describe the significance of photosynthesis to the development of the Earth's atmosphere.
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Photosynthesis changed the Earth's atmosphere by liberating oxygen gas
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Photosynthesis necessarily gives off oxygen as a byproduct.
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False
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In addition to O2 releasing photosynthesis, what else must occur for O2 to build up in the atmosphere
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Organic carbon must be buried
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Which of the following cycles began near the beginning of the "boring billion"?
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The supercontinent cycle
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Why is the Mesoproterozoic called the "boring billion"?
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It was a period that no major changes in Earth's systems occurred, a period of relative stasis
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Why are cratons the key to our understanding of the Archean and Proterozoic Earth?
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They are easily created and destroyed; hence, they show us the processes that occurred during Earth's history
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Describe the significance of the "Canfield" ocean that existed during the "boring billion".
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The ocean allowed both sulfur-consuming bacteria and oxygen-producing bacteria to live in equilibrium
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Why did the breakup of Rodinia create conditions that led to a major icehouse stage of Earth's history?
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Breakup caused lots of continental shelf area and algae bloom and burial—CO2 converted into O2
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What permanent changes did the Snowball Earth events create in the Earth's systems?
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It led to the permanent buildup of oxygen in Earth's atmosphere
