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| Proposed Sequence to Origin of Life |
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Definition
1) Abiotic synthesis of small organic molecules, such as amino acids and nucleotides
2) The joining of these small molecules (monomers) into polymers, including proteins and nucleic acids
3) The packaging of these molecules into "protobionts"
4) The origin of self-replicating molecules that eventually made inheritance possible |
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Definition
| Aggregates of abiotically produced molecules surrounded by a membrane or membrane-like structure; droplets with membranes that maintained an internal chemistry different from that of their surroundings. |
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| An enzyme-like RNA molecule that catalyzes reactions during RNA splicing. |
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| A method paleontologists use for determining the ages of rocks and fossils on a scale of absolute time, based on the half-life of radioactive isotopes. |
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| The number of years it takes for 50% of the original sample to decay; unaffected by temperature, pressure, and other environmental variables. |
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| A reversal of the polarity of Earth's magnetic field. |
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| The division of Earth's history into time periods, grouped into three eras: Archaean, Proterozoic, and Phanerozoic; further subdivided into eras and epochs. |
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| Two Most Major Instances of Mass Extinction |
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Definition
1) At the end of the Paleozoic era appx 250 million years ago; between Permian and Triassic periods.
2) At the end of the Mesozoic era appx 65 million years ago; between the Cretaceous and Paleogene periods. |
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| Oldest known fossils; rocklike structures composed of many layers of bacteria and sediment. |
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| A model of the origin of eukaryotes consisting of a sequence of endosymbiotic events in which mitochondria, chloroplasts, and perhaps other cellular structures were derived from small prokaryotes that had bene engulfed by larger cells. |
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Definition
| The production of a new genome through the transfer of part of the genome of one organism to another organism. |
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| Snowball Earth Hypothesis |
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Definition
| The hypothesis that glaciers covered the planet's landmasses from pole to pole 750-570 million years ago, confining life to very limited areas. |
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Definition
| Collections of autonomously replicating cells. |
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| The latest supercontinent that formed 250 million years ago. |
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