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By Giovanni Casotti Department of Biology West Chester University, West Chester, PA Lost? Ask a Turtle: Navigation and Migration in Loggerheads.

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Presentation on theme: "By Giovanni Casotti Department of Biology West Chester University, West Chester, PA Lost? Ask a Turtle: Navigation and Migration in Loggerheads."— Presentation transcript:

1 by Giovanni Casotti Department of Biology West Chester University, West Chester, PA Lost? Ask a Turtle: Navigation and Migration in Loggerheads

2 Terminology Navigation o Moving along a course Migration o Moving from one region to another Homing o Returning back to a specific point 2

3 Migration Reproductive success –Sockeye salmon (lifecycle migration and homing) 3

4 Migration Reproductive success –Loggerhead turtles 4 −Elephant seals

5 Case Case Study Loggerhead turtles 1.How do hatchlings navigate to the ocean? What dangers are faced by newly emerging turtles hatchlings? 2.Once in the water, what mechanism do hatchling turtles use to make their way toward open ocean? 3.Once off the coast, juveniles make their way to the North Atlantic Current (Gyre). Describe this pathway. 5

6 Migration Food acquisition –Humpback whales 6

7 Navigation Strategies Trail following – Employed by invertebrates only (ants) 7 Piloting ‒Using landmarks to navigate (pigeons)

8 Navigation Strategies Path integration –Employed by invertebrates only (ants) 8 Return journey

9 Navigation Strategies Map and compass navigation –Used by long distance migrators (whales and turtles) 9

10 Terrestrial Animals Compass navigation –Using Earth’s magnetic field 10

11 Case Study Watch the video on turtle navigation: http://www.youtube.com/watch?v=LbiBXRtiVrg 11

12 Magnetite Receptors Located in beaks of birds 12

13 Magnetite Receptors 2 possible mechanisms of action 13

14 Case Study Question 4.How do hatchling and adult turtles find their way along their migratory pathway? What methods did scientists use to identify the mechanism responsible for long distance navigation in sea turtles? 14

15 Navigation Strategies Compass navigation –Using the sun (starlings) 15 Sunlight

16 Navigation Strategies Compass navigation –Using the stars (Indigo buntings) 16

17 Navigation Strategies Olfactory cues: Detection of dimethyl sulphide (DMS) 17

18 Case Study Questions 5.Birds might use DMS to navigate. What produces DMS and what methods did researchers use to determine this? In what oceans has DMS been measured? 6.What about seals? Why do the researchers think that seals use visual cues to navigate? 18

19 Case Study Questions 7.Why did the researchers discount the possibility of geomagnetic, celestial, acoustic and olfactory cues as navigational tools in seals? 8.Migrating in the open ocean can be more challenging than a land migration. Describe these differences. 19

20 Image Credits Slide 1 Photo ©Nexus7 | Dreamstime.com, ID#28139654, licensed for use. Slide 2 Photo by Hila Shaked, “Hatchling Loggerhead sea turtles near Atlit, Israel, on their way to the ocean,” http://commons.wikimedia.org/wiki/File:Hatchling_Loggerhead_Sea_Turtles_near_Atlit_Israel.jpg), CC BY-SA 3.0. Slide 3 (left) Photo of spawning sockeye salmon by Theinterior, http://commons.wikimedia.org/wiki/File:SockeyeSpawn_inAdams.JPG, CC BY 3.0. Slide 3 (right) Figure 5 from: Lohmann, K. J., Lohmann, C.M.F., and Endres, C.S. 2008. The sensory ecology of ocean navigation. J Exp Biol June 2008 vol. 211 no. 11 1719- 1728. http://jeb.biologists.org/content/211/11/1719/F5.expansion.html#ref-19. Slide 4 (left) Crop of Fig 3 in: Lohmann, K. J., Lohmann, C. M. F. and Endres, C. S. 2008. The sensory ecology of ocean navigation. J. Exp. Biol. 211: 1719–1728. Available online at http://jeb.biologists.org/content/211/11/1719.long. Last accessed March 27, 2014. CC-BY 3.0. Slide 4 (right) Distribution of the northern elephant seal (dark blue: breeding colonies; light blue: non-breeding individuals), by Mirko Thiessen, http://en.wikipedia.org/wiki/File:Mirounga_angustirostris_distribution.png, CC BY-SA 3.0. Slide 6 National Park Service, US Department of the Interior. Humpback Whale (Megaptera novaeangliae). http://www.nature.nps.gov/biology/migratoryspecies/humpbackwhale.cfm. Slide 7 (left) Photo of ant trail by Wikipedia User:Fir0002, http://commons.wikimedia.org/wiki/File:Ant_trail.jpg, CC BY-SA 3.0. Slide 7 (right) Julius Neubronner's tiny cameras strapped to homing pigeons, http://commons.wikimedia.org/wiki/File:Pigeoncameras.jpg, public domain. 20

21 21 Slide 8 Created by author. Slide 9 NASA, http://www.nasa.gov/images/content/607968main_geomagnetic-field-orig_full.jpg. Slide 10 Schematic of experimental setup and photo of turtle in harness provided by The Lohman Lab, Department of Biology, University of North Carolina, Chapel Hill, NC (http://www.unc.edu/depts/geomag/), used with permission. Slide 12 Figure 7 in: Pósafi, M., and R. E. Dunin-Borkowski. 2009. Magnetic nanocrystals in organisms. Elements 5: 235-240. Used with the permission of the Mineralogical Society of America. Slide 13 Panels B and C of Figure 4 in: Pósafi, M., and R. E. Dunin-Borkowski. 2009. Magnetic nanocrystals in organisms. Elements 5: 235-240. Used with the permission of the Mineralogical Society of America. Slide 15 Adapted from Fig. 27.21, page 603 In: Hickman CP, Roberts, L.S. Keen, SL, Larson, A., I’Anson, H and Eisenhour, D.J. (2008). Integrated Principles of Zoology. 14 th ed. McGraw-Hill, Boston. ISBN 978-0-07-722126-3. Slide 16 Modified from: Emlen, ST (1967). Migration orientation in the Indigo Bunting, Passerina cyanea: Part 1 Evidence for the use of celestial cues. The Auk, 84: (3) 309-342. https://sora.unm.edu/sites/default/files/journals/auk/v084n03/p0309-p0342.pdf Slide 17 Figure 1 in: Nevitt, G. A. and Bonadonna, F. 2005. Sensitivity to dimethyl sulphide suggests a mechanism for olfactory navigation by seabirds. 1: 303305. Available online at http://rsbl.royalsocietypublishing.org/content/1/3/303.full. Used with permission.


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