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5 Cards in this Set
- Front
- Back
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Summarize the theories for how organic molecules first formed on Earth.
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Alexander Oparin hypothesized that energy from the sun, lightning, and Earth's heat triggered chemical reactions to produce small organic molecules.
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Explain the relationship between early photosynthetic autotrophs and the eventual rise of aerobic life forms.
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Early autotrophs formed glucose by chemosynthesis instead of photosynthesis. Photosynthesizing prokaryotes capable of releasing oxygen from water evolve. Oxygen began to appear in air and aerobic life formed.
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Explain how the evolution of photosynthetic organisms helped protect life from the sun's ultraviolet radiation.
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The sun's rays would have concerted much of the oxygen into ozone molecules, providing an ozone layer.
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How did Pasteur's experiment finally disprove spontaneous generation?
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Pasteur filled flasks with broth which was boiled and used to kill all microorganisms. The flask allowed air to enter, but prevented microorganisms from entering the flask. He then tilted a flask, allowing the microorganisms to enter. The microorganisms soon grew in the broth, showing they come from microorganisms.
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How would the increasing number of photosynthesizing organisms on Earth have affected both Earth and its other organisms?
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It provided oxygen in Earth's atmosphere. It also formed ozone molecules, which would form an ozone layer.
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