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GTS (update your ToC ) Geologic Time Scale : How is the GTS organized? grouped by changes in global biotic turnover (many changes in flora/fauna species across the world in a relatively short time span) b. What are the units used to organize these events?
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GTS (update your ToC) • Geologic Time Scale: • How is the GTS organized? • grouped by changes in global biotic turnover (many changes in flora/fauna species across the world in a relatively short time span) • b. What are the units used to organize these events? • Eon Era Period Epoch • c. Is the GTS “scaled” mathematically? Explain. • No. New divisions are based on geologic and biotic changes on earth, NOT based on equal intervals of time. • d. What appears to be the major emphasis on the GTS? • changes in fauna in the very recent history (latest 1/2 Billion years)
GTS (cont) • Geologic Time Scale: • e. Why are new divisions in time made? • climate change, appearance of fossils of new type of family, disappearance of many families or species/mass extinction events • f. What patterns can you find? • * Greater diversity closer to “today” • * species appears, species disappear – “extinction happens” • * flora and fauna start in the water and later show up on the land • * life-forms generally become physically more sophisticated