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Announcements

Announcements. Exam 3 and second project presentations will be during the final exam period: Monday December 10 @ 10:30am

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Announcements

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  1. Announcements • Exam 3and second project presentations will be during the final exam period: Monday December 10 @ 10:30am • Homework: Chapter 23 # 27 & 28 +What is your numerical answer to the Drake equation. Give your estimate for the value of each term in the equation and why you think it is so. • Solution to all homework (except this week) is posted. This week’s solution will be posted next Friday.

  2. The Mathematics of Evolution

  3. Small mutations lead to a diversification of species

  4. Occasionally, a major mutation improves the species

  5. Example Problem When a mutation occurs it either gives the new form an advantage or disadvantage in breeding. Usually, the advantage is small but if a major advantage occurs, the new form quickly dominates. The percent of the population the old form represents after n generations is (pr)n where pris the percent difference in the reproductive rate. If Cro-Magnon man had a 10% reproduction advantage over Neanderthal man, what percentage of the population was Neanderthal after 20 generations?

  6. Example Solution Reproductive disadvantage is 90% = 0.90 Number of generations is 20 If a single generation is 20 years, this is only 400 years. In a span of 1,000 years the number is down to 0.515%

  7. The Drake Equation How many intelligent species are out there trying to communicate with us right now? This only considers species within the Milky Way galaxy

  8. F = total number of stars in the Milky Way We know this number with a fair degree of certainty. Roughly 300 billion

  9. fp = fraction of stars with planets Stellar formation theory suggest this number should be fairly close to one

  10. npm = number of planets or moons per solar system that are capable of supporting life

  11. fl = fraction of planets that are capable of supporting life that actually develop life

  12. fc = fraction of planets with life that develop intelligence and the technology to communicate

  13. L = likelihood the communicating civilization exists today

  14. What is the answer to the Drake Equation? The answer depends on your estimation of things that aren’t well known. Because so many of the terms are basically guesses, the range of answers is very large Zero or tens of thousands?

  15. The Message we sent from Arecibo in 1974 Can you read this? Do you think ET will be able to read it? What kind of answer will ET send back and will we be able to read it? Check out the Wikipedia page on the Arecibo Message

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