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5 to 100 million species of organisms on Earth

5 to 100 million species of organisms on Earth. All organisms on Earth are genetically related. “Tree of Life”. All organisms are genetically related. Eukaryotes. Archaea. Bacteria. P HYLOGENY History of lineages changing through time. NSF Assembling the Tree of Life (ATOL) Program.

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5 to 100 million species of organisms on Earth

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  1. 5 to 100 million species of organisms on Earth

  2. All organisms on Earth are genetically related

  3. “Tree of Life” All organisms are genetically related Eukaryotes Archaea Bacteria

  4. PHYLOGENYHistory of lineages changing through time

  5. NSF Assembling the Tree of Life (ATOL) Program “Increased knowledge of phylogenetic relationships will improve human health, push the frontiers of comparative developmental biology, meet threats to agriculture and forestry from invasive species and pests, and improve management of our natural resources.” http://atol.sdsc.edu

  6. http://tolweb.org

  7. > 6000 web pages with scientific content > 500 scientific contributors Scientific Core Content

  8. > 6000 web pages with scientific content Most pages are still under construction…

  9. > 20,000 images, videos, audio files > 6000 web pages with scientific content > 200 treehouses (learning materials) Some content is provided by amateur contributors

  10. Leaf pages Bembidion zephyrum Rosa davurica Insects Branch pages Eukaryotes Life on Earth The structure of the Tree of Life web site illustrates phylogenetic relationships

  11. http://tolweb.org

  12. HomoplasyThe Scourge of Phylogentic Biologists!

  13. Reconstructed Tree A D A D B C many informative changes B C few informative changes Homoplasy in Sequence Data:Long Branch Attraction True Tree

  14. How to avoid long branch attraction? • Exclude long-branch taxa • Exclude characters that show evidence of excessive homoplasy • Use other inference methods that take branch lengths into account • Split long branches by adding more taxa

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