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Lecture 1
Origins
Question | Answer |
---|---|
When was our solar system formed? | about 4.5 billion years ago |
What sort of state was our solar system like in the beginning? | gassy |
Earth is rocky/solid making it a what sort of planet? | Terrestrial Planet |
Gravity pulled what two elements inward to form the present day Earth's core? | iron and nickel |
Lighter elements rose to the surface forming what two parts of the Earth? | the mantle and crust |
The Earth's core remains partially molten through what? | Radioactive Decay |
Early atmosphere was composed mostly of what 8 things? | water vapor. nitrogen gas. carbon dioxide. methane. carbon monoxide. sulfur dioxide. HCl. ammonia. |
What elements was not in the early atmosphere? | oxygen |
What is a major determinant of the salinity of the ocean? | chlorine |
The ocean is estimated to how many years old? | about 3.8 billion years old |
What two conditions are critical to development of life? | lack of oxygen and the presence of water |
Cells are composed of proteins, carbohydrates, lipids, nucleic acids, etc that are assembled from using what from the environment? | energy |
The two scientists that created the early atmosphere model where? | Miller, Urey |
Earliest forms of life on Earth arose when? | about 3.8 billion years ago |
Early cells were? | prokaryotic, probably just membrane bags of self-replicating RNA, DNA, other molecules. |
Populations diverged in two major directions... | Archaea and Eukarya (Eukaryotes), Bacteria |
Percentages of present-day atmosphere... | 78% Nitrogen, 21% Oxygen, <1% Argon, <0.03% Carbon Dioxide |