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Biogeography: Influence of Temperature on Needlefish Distribution

Explore how temperature affects the distribution of needlefish species. Not all species occur in all places and their occurrence is strongly influenced by water temperature. Discover examples of Gondwanaland and Lauratian distributions in various fish taxa and learn about the hypotheses explaining the distribution of cichlids.

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Biogeography: Influence of Temperature on Needlefish Distribution

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  1. Lecture 10. Wednesday, September 17. 1. Biogeography - Why do things occur where they do?

  2. Needlefish distribution is strongly influenced by temperature. Occur in water above 23.9C.However - not all species occur in all places.

  3. www.scotese.com

  4. www.scotese.com

  5. Gondwanaland Distribution Example 1 - Cichlids

  6. Gondwanaland Distribution Example 2 - Characiformes

  7. Gondwanaland Distribution Example 3 - Osteoglossids

  8. Lungfishes • Distribution thought to reflect Gondwana connections of southern continents

  9. Lauratian Distribution Example #1 - Percidae

  10. Lauratian Distribution Example #2 - Esocidae

  11. Cypriniformes, Catostomidae 13 genera 70 species

  12. Lauratian Distribution Example #3 - Cypriniformes 53 genera 286 species

  13. www.scotese.com

  14. Gondwanaland Distribution Example 1 - Cichlids

  15. Cichlidae - 900 species in African rift lakes = species flocks L. Victoria

  16. Molecular Clock Data Indicate that Cichlids diverged after breakup of Gondwanaland

  17. Group Activity #1 -Draw the phylogenetic tree & distinguishing traits for: group a - Myxiniformes, Gnathostomata, Chondrichthyes, Osteichthyes group b - Petromyzontiformes, Elasmobranchii, Holocephali, Sarcopterygii, Actinopterygii group c - Elasmobranchii, Holocephali, Sarcopterygii, Actinopterygii group d - Myxiniformes, Petromyzontiformes, Chondrichthyes, Sarcopterygii

  18. Group Activity #3 - Design a dichotomous key that would allow one to distinguish these groups For example . . . Step 1 - lacks vertebrae --> Myxiniformes if not --> go to step 2 Step 2 - lacks jaws --> Petromyzontiformes if not --> go to step 3

  19. Review Questions: 1. Distinguish between the “Intrinsic Limitations” hypothesis versus the “Vicariance” hypothesis for the distribution of fish. What assumptions do each make concerning dispersal? 2. List 2 major geological factors that can affect fish distributions. How does glaciation affect fish distribution? 3. List 4 taxa that show a “Gondwanaland” distribution. Which ones have clear-cut fossil support? List 3 taxa that show a “Lauration” distribution. 4. What were the 3 hypotheses for explaining the distribution of cichlids? What evidence is there to support (or reject) each one? How did scientists calibrate a “molecular clock” for cichlids? How did they use it to estimate the origin of cichlids? Do you think it likely that cichlids migrated between Africa & South America? What is neutral DNA? 5. Speculate on the relative roles of vicariance versus dispersal for marine versus freshwater fish. Do you think their relative importance differs between saltwater and freshwater fish? What evidence does your book present on this matter?

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