Flashcard Set Preview
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| 1 |
How old is Earth and how do we know?
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4.55-4.56 billion years old. We know this because astronomers have done radiometric dating...
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how old is the universe and how do we know?
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the universe is 13.7 billion years old and we know this because astronomers have measured trajectories...
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What chemicals were in early Earth's atmosphere and why was this beneficial to forming life?
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Methane, ammonia, water vapor, and hydrogen. this was beneficial for life because the early...
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why would oxygen make life impossible in the beginning?
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life could not arise from inorganic compunds if oxygen was present in the beginning because...
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What is the primordial soup model?
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This model suggests that the origin of life arose from the right ratio of chemicals mixed...
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| 6 |
What was the Miller-Urey experiment?
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This experiment simulated early earth by isolating hydrogen, ammonia, methane, and water vapor,...
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| 7 |
What were the first cells on Earth like?
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autotrophs that gained energy from inorganic compounds like sulfur and iron compounds.
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| 8 |
describe plate tectonics and their implications.
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the fact that the Earth's crust is broken into pieces. the crashing/touching/rubbing of plates...
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what is pangea and how many years ago did it exist?
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Pangea was Earth's supercontinent that existed 250 million years ago. about 180 million years...
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| 10 |
what is the evidence for the existence of Pangea?
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South America and African coastlines fit togethersimilar plant and animal fossils were found...
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| 11 |
What are the four great eras of the geological time scale? (oldest to newest)
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Precambrian, paleozoic (origin of most modern animal phyla), mesozoic, cenozoic (we are in...
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| 12 |
What is relative dating?
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when sedimentary rock forms, layers pile on top of layers. a layer is called a stratum. fossils...
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| 13 |
What is an isotope?
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the same atom with a different number of neutrons.
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| 14 |
describe radiometric dating.
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radioactive isotopes decay into more stable elements at predictable rates. scientists use half...
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| 15 |
Describe radiocarbon dating. How many years have to go by before is it no longer accurate?
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Carbon-14 decays into Nitrogen-14. Results are no longer valid after 50,000 years.
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| 16 |
What is dendrochronology?
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absolute dating technique. One ring is produced on a tree each year.
by matching tree growth...
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| 17 |
How many species have we documented on earth?
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1.8 million documented species
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| 18 |
What are the three domains of life and which ones are prokaryotic
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bacteria, archaea, and eukaryotes. Bacteria and archaea are prokaryotic.
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How many species to we estimate to exist on earth
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between 10-100 million
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