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SCIENCE NEWS

SCIENCE NEWS . Google wants to buy, sell electricity in US http:// news.yahoo.com/s/afp/20100108/tc_afp/usitinternetcompanygoogleelectricity Experts: Cold snap doesn't disprove global warming http :// news.yahoo.com/s/ap/20100107/ap_on_sc/sci_big_chill. What do you think? .

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SCIENCE NEWS

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  1. SCIENCE NEWS • Google wants to buy, sell electricity in US • http://news.yahoo.com/s/afp/20100108/tc_afp/usitinternetcompanygoogleelectricity • Experts: Cold snap doesn't disprove global warming • http://news.yahoo.com/s/ap/20100107/ap_on_sc/sci_big_chill

  2. What do you think? • How was the Earth created? • What was the earth like after it was formed?

  3. What are the benefits of studying Fossils and the Rock Record? Geologist can reconstruct aspects of earth’s history

  4. Geologic Time Scale Enables scientist to find relationships among geological events, environmental conditions and fossilized life forms

  5. Geologic Time Scale • Geologic time scale – Earth history • Subdivides geologic history into time units • Time units are based largely on the fossils within the rocks • Originally created using relative dates

  6. Structure of the geologic time units scale • Eonsare subdivided into • Eras are subdivided into • periodsare subdivided into • epochs • See text p 591

  7. Eon – the greatest expanse of time • Phanerozoic– “visible life”, most recent eon • Proterozoic– before life • Archean – ancient • Hadean– mythical subterranean world of departed spirits, oldest eon • Precambrian: Proterozoic, Archean, Hadean

  8. Eons • Largest of the time units • Three earliest eons make up 90% of geologic time also know as Precambrian • Fossil evidence suggest simple life forms in the Archean Eon • At end of Proterozoic Eon life evolved into complex organisms • What eon are we currently in?

  9. What do you think was alive in the Hadean and early Archean eon? Bacteria

  10. Era – subdivision of an eon • 10 – 100 millions of years • Defined by life forms found in the rocks Greek roots • Paleo = old • Meso = middle • Ceno = recent • Zoic = of life Example: Mesozoic = middle life

  11. Periods • 10 of millions • Named for geographic region in which rocks or fossils characterizing the age was first observed and described

  12. Epochs • 100 to Millions of years • Rocks & sediments are most complete less time for weathering and erosion

  13. Evolution & Geologic Time

  14. What Eon, Era, Period and Epoch are we currently living in? • Phanerozoic, • Cenozoic • Neogene • Plesitocene

  15. When?? • What eras were the age of the dinosaurs? • What era did mammals increase in numbers and diversity? • What era did the Appalachian Mountains start to form?

  16. ANY QUESTIONS?

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