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Reviewing the Mystery…

Reviewing the Mystery…. Why is the dark form becoming more common in areas downwind of manufacturing centers?. The Peppered Moth. Biston betularia f. typica Biston betularia f. carbonaria. 1950. Centers of pollution. Frequency of dark form. Glasgow. Manchester. London . 1600. 1900.

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Reviewing the Mystery…

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  1. Reviewing the Mystery… Why is the dark form becoming more common in areas downwind of manufacturing centers?

  2. The Peppered Moth Biston betularia f. typica Biston betularia f. carbonaria

  3. 1950 Centers of pollution Frequency of dark form Glasgow Manchester London 1600 1900 2000 1800 1700

  4. Light & Dark Forms lichen-covered tree soot-covered tree

  5. Natural Section & the Mystery Phenomenon J.W. Tutt (1858-1911) E.B. Ford (1901-1988) • The spread of the dark form is due to its physiological superiority over the light form. • The spread is limited to areas darkened by pollution owing to the handicap of dark coloration in unpolluted environments.

  6. Mystery PhenomenonPart 3

  7. H.B.D. Kettlewell The peppered moth Biston betularia (1907-1979)

  8. Kettlewell’s Investigations Mark-release-recapture experiment

  9. Film: Evolution in Progress

  10. Kettlewell’s m-r-r results 2x as likely to survive.

  11. Kettlewell’s m-m-r results 2x as likely to survive.

  12. Observations:bird predation order

  13. What are experiments?

  14. Are experiments necessary for progress in science?

  15. Have Kettlewell’s experiments convinced you that Ford’s theory is correct?

  16. The Mystery Continues • Kettlewell’s Conclusions • Not universally accepted • Issues with experimental design. • Lack of knowledge of behavior & ecology of moth. • Other scientists worked on the moth

  17. M. E. Majerus Ford

  18. Problems & Solutions Kettlewell Biston betularia found at rest on a horizontal tree branch (M. Majerus 2009)

  19. Expectations J.W. Tutt (1858-1911) M.E. Majerus (1954-2009)

  20. And What of the Moth? Centers of pollution Frequency of dark form Glasgow Manchester London 1600 1900 2000 1800 1700

  21. The Great Smog of 1952 • 4- day smog event • Reported that 4,000 people died • Recent research puts deaths at 12,000 • 10,000 people ill Nelson's Column, London

  22. Clean Air Act 1956 • Britain now had strict air pollution laws in place. • What happened to the frequency of the dark form?

  23. The Mystery Phenomenon Cooke Majerus ? Kettlewell Tutt Harrison Ford 165 years & counting

  24. Is that the Complete Story? ?

  25. Details, details. • 1’. The peppered moths has two dark forms, not one. Biston betularia f. typica Biston betularia f. carbonaria Biston betularia f. insularia

  26. When is it Enough? • Carbonaria is common in some rural areas (unpolluted). • Dark forms of other species have evolved for other reasons. • Scientific controversies not covered in detail.

  27. What Should Science Teachers Do? How much detail should science teachers give? How can simplified versions of a scientific account be useful? What problems can arise using simplified versions? Is there ever a “complete” version?

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