BILD 3 Lecture Notes - Lecture 3: Precambrian, Paleozoic, Mesozoic
27 Oct 2016
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Document Summary
Chains of rna may have been the first things to replicate and evolve. Molecule needs to replicate, catalyze reactions, and store hereditary information. The first genetic material was probably rna, not dna. Rna molecules called ribozymes can catalyze: replication, self-splicing, other reactions. You need dna to make proteins, and proteins to make dna (chicken and the egg problem) Realized that rnas can replicate themselves and serve as biological catalysts. Just because rna predates dna doesn"t mean rna is the first. Probably created much later than the first signs of life on earth. Precambrian era - first 4 billion yrs ago. These different periods had major shifts/events that caused these changes in periods. Geographic bias: buried in shallow lake where there is a lack of oxygen (not mountain tops or rainforests. Taxonomic bias: structure of your bones and material used to fossilize. Temporal bias: there aren"t that many rocks from 2. 5 bya. The chance that they have survived is very low.
