BILD 3 Study Guide - Final Guide: Particulates, Gradualism, Background Extinction Rate
30 May 2016
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Organic samples: uranium-235"s half-life is 71. 3 million years b. i. Rocks and other minerals: uranium-238"s half-life is 4. 5 billion years. Identify what starts the clock for carbon-14 vs. uranium dating samples: carbon-14"s clock starts when the organism dies, uranium-235"s clock starts with rock solidifies. Other people, other conditions: lots of other organic molecules, including amino acids, nucleotides, and sugars: there is still a lot we don"t know about how life arose, origin of cells, the earliest life was probably non-cellular a. i. 3. 5 billion years ago: first fossils of cells: stromatolites, photosynthetic cyanobacteria found ~3. 5 bya that persist today, oldest known fossils are of stromatolites c. The chloroplast and mitochondria has their own ribosomes, double cell: first evidence of multicellular life. membranes, and has their own dna, the oldest fossils of eukaryotic cells are about 2. 1 billion years" old a. i. Eukaryotic algal fossils from lake superior: multicellularity has arisen many times b. i.
