Lecture 04 - BIOLOGY 1001: LECTURE 4 EVIDENCE FOR EVOLUTION...

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BIOLOGY 1001: LECTURE 4 EVIDENCE FOR EVOLUTION I. Fossil record - Sedimentary rocks record history: lower levels are older and are overlain by younger layers. Hence, different layers indicate relative ages (e.g., Grand Canyon). A. Dating of fossils 1. Relative dating methods: examine the chronological relationships among the fossils or layers of rocks. This itself can be done by two methods: a. Superposition: relative positions of layers of rocks allow chronological ordering. b. Faunal succession: Use of common, widespread fossils that characterize a well- defined time period (index fossils). 2. Absolute dating methods (geochronology) - measure decay of radioisotopes (isotope = atoms that differ in numbers of neutrons) by determining proportions of original (parent) and decayed product (daughter). Examples: 14 C ==> 14 N; 40 K ==> 40 Ar B. Types of fossils 1. Impressions - footprints, tailprints, full body prints 2. Remains - preserved organic material (e.g., leaves), amber-preserved insects
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This note was uploaded on 01/20/2010 for the course BIOL 1001 taught by Professor Fall during the Fall '08 term at Minnesota.

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Lecture 04 - BIOLOGY 1001: LECTURE 4 EVIDENCE FOR EVOLUTION...

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