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Chp. 22 bio

the origin and history of life

QuestionAnswer
fossils are perserved remains of past life on earth. includes bones, shells, and footprints.
Radioisotope dating/ carbon dating method used for estimating the age of the fossil
hlaf-life is the amount of time required for a radioisotope to decay to half of its initial amount.
Earth is estimated to be 4.55 billion years old.
Life began on earth between 3.5-4 billion years ago
Prokaryotic cells around archaean eon - 3.5bya
Eukaryotic cells aroused about a billion years later. 2.5bya
Multicellular eukaryotes appeared another billion years later. 1.5bya
cenozoic era is present day
RNA world rna is ancient molecule, scientist favor rna as most permitive oldest. 1. ability to store info. 2. self replicate 3. enzymatic function ribozymos.
Created by: 1574238891
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