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Darwin called the evolution of the Angiosperms a “ Perplexing phenomenon”

Darwin called the evolution of the Angiosperms a “ Perplexing phenomenon” …and in a letter to Joseph Hooker he called them an…. “Abominable Mystery” —Charles Darwin in a letter to Sir Joseph Hooker, 1879. Three Main Questions 1. Where did they come from?

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Darwin called the evolution of the Angiosperms a “ Perplexing phenomenon”

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  1. Darwin called the evolution of the Angiosperms a “ Perplexing phenomenon” …and in a letter to Joseph Hooker he called them an…

  2. “Abominable Mystery” —Charles Darwin in a letter to Sir Joseph Hooker, 1879. Three Main Questions 1. Where did they come from? 2. How did they diversify so quickly? 3. How do they maintain high diversity? www.jdhooker.org.uk

  3. Stamen series from leaf-like to a slender filament.

  4. Anthers with rust colored pollen Lilium philadelphicum, Wood Lily, Liliaceae

  5. Narcissus pollen is typical monocot pollen (monosulcate)

  6. Arabidopsis pollen is tricolpate (three long grooves) and is typical for a large number of dicots.

  7. Helianthus (Asteraceae) pollenremf.dartmouth.edu/images/botanicalPollenSEM/image/10asteraceae(helian.)pollen.jpg&imgrefurl=http://remf.dartmouth.edu/images/botanicalPollenSEM

  8. Ambrosia - Ragweed! Pollen

  9. Oak Pollen- wind dispersed

  10. Cathy Small ‘09 Impatiens pollen is tetracolpate (with 4 slits). Note sculpting of exine, slits for pollen germination, and raphide crystals.

  11. Sepal modified to be a nectar producing spur Impatiens pallida

  12. Raphide Crystals Pollen

  13. Rhingia naisica eating pollen of Impatiens pallida

  14. Sagina nodosa (Caryophyllaceae) Pollen Tube Stigmatic papillae Pollen Grain -polyporate (with many round pores)

  15. Pollen grains germinate to form the male gametophyte

  16. 1 2

  17. 3 4 2nd mitotic Division 5 Meiosis, 3 products Disintegrate leaving one megaspore 1st mitotic division

  18. Female Gametophyte (embryo sac) Polar Nuclei 3rd Mitotic Division All megaspore images from: http://images.google.com/imgres?imgurl=www.botany.hawaii.edu/faculty/webb/BOT410/Angiosperm

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