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Bi 1 Lecture 29 Thursday, June 2, 2005 Evolution 3. Voyages to the Galapagos; The physiology of Diving Mammals

“Study nature, not books” (Louis Agassiz) . Bi 1 Lecture 29 Thursday, June 2, 2005 Evolution 3. Voyages to the Galapagos; The physiology of Diving Mammals. Announcements on the Bi 1 Web page: http://www.its.caltech.edu/~bi1/schedule.html.

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Bi 1 Lecture 29 Thursday, June 2, 2005 Evolution 3. Voyages to the Galapagos; The physiology of Diving Mammals

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  1. “Study nature, not books” (Louis Agassiz) Bi 1 Lecture 29 Thursday, June 2, 2005 Evolution 3. Voyages to the Galapagos; The physiology of Diving Mammals

  2. Announcements on the Bi 1 Web page: http://www.its.caltech.edu/~bi1/schedule.html Review Session takes place here, today, here, 4 - 6 PM. Sections meet as usual today and tomorrow. The final exam is posted Thursday (today) 6 PM; Due Fri 6/10 4:30PM in the Bi 1 Closet Graduating seniors: papers are due today 5 PM in the Bi 1 Closet

  3. Acknowledgements “It takes a village to teach Bi 1 at Caltech” TAs, both grads and undergrads Professional staff: Dr. Jane Mendel, Head TA: Sections and grading Patricia Mindorff, communications David Mathog, Molecular Graphics Eric Slimko, Webmaster Biology Electronics shop computer support: Mike Walsh and Pam Fong Guest lecturers: Robert Freedman David Anderson Cameo appearances from Biology Faculty Advice from other Core Curriculum Resources You, the students

  4. The Voyage of the HMS Beagle 1831-1836 Charles Darwin (born 1809), unpaid naturalist Azores Cape Verde Islands Canary Isles Cocos Islands Tahiti Bahia Rio de Janeiro King George Sound Cape of Good Hope Galapagos Islands 35 day visit Valparaiso Montevideo Tasmania New Zealand Falkland Islands journey out journey home Cape Horn

  5. Equator Punta Espinoza Age of the archipelago: ~ 1 million yr British Admiralty chart of the Galapagos Islands, based on the Beagle’s observations

  6. 13 Species, each endemic to the islands • El Nino poses a survival challenge • Highly specialized beaks • Observable evolution in beak size • Distinctive feeding habits Darwin’s Finches(5 genera, including Geospizia) cactus finch ground finch tree finch

  7. The voyage of the Beagle convinced Darwin that 1. Members of the same species often change slightly in appearance after becoming geographically isolated from each other 2. Organisms living on oceanic islands often resemble organisms found living on a close mainland 3. Factors other than or in addition to climate play a role in the development of plant and animal diversity 4. Organisms of the past and present are related to one another (but there are no fossils in the Galapagos)

  8. "The distribution of the tenants of this archipelago would not be nearly so wonderful, if, for instance, one island had a mocking-thrush, and a second island some other quite distinct genus.... But it is the circumstance, that several of the islands possess their own species of tortoise, mocking-thrush, finches and numerous plants, these species having the same general habits, occupying analogous situations, and obviously filling the same place in the natural economy of this archipelago, that strikes me with wonder...." Darwin, The Voyage of the Beagle http://www.literature.org/authors/darwin-charles/the-voyage-of-the-beagle/chapter-17.html

  9. Finch family tree based on a 660-nt sequence Molecular Biology and Evolution 18:299-311 (2001) Darwin’s Galapagos finches .01 change per position

  10. Red-Footed Booby (Ben Lester) Blue-Footed Booby

  11. Masked booby A recently discovered a behavior, called siblicide, occurs among booby chicks. The larger chick always kills the younger chick, sometimes aided by the parents. Scholars debate the selective advantage of such behavior. Perhaps the parents succeed better by insuring the survival of at least one chick.

  12. Male Frigate Bird Displaying no oil on feathers cannot land on water steals other birds’ fish

  13. Galapagos Waved Albatrosses in Courtship 2 m wingspan

  14. Video of Galapagos Waved Albatrosses in Courtship

  15. photo by Ben Lester Female Albatross on the nest

  16. photo by Ben Lester

  17. The Galapagos tortoises reach sexual maturity at the age of 40 and have clutches of 2 - 26 eggs. Eggs hatch at 85 -180 d.

  18. Galapagos Penguins World’s Northernmost population of penguins. After "El Nino" in 1983 the population decreased from 12,000 to just 2,000 birds.

  19. Marine Iguanas

  20. Marine Iguana feeding Marine iguanas feed once a day. The mature lizards swim out through the tidepools to dive to the bottom for algae; smaller iguanas feed off the rocks in the tidal zone. An iguana may lose up to 10 degrees C of body temperature on these feeding missions. Because they are cold-blooded ("ectothermic") , iguanas must bask on the hot lava rocks throughout the day until they raise their internal temperature.

  21. The increased rainfall that accompanies El Niño results in greater food availability for most terrestrial organisms in the Galápagos, but marine life generally suffers from the higher water temperature, which decreases the amount of dissolved oxygen. Green and red algal species, which are the marine iguanas' preferred food, disappear and are replaced in intertidal areas by brown algae which iguanas find hard to digest. Up to 90% of marine iguana populations on islands can die of starvation as a result of these environmental changes. During a recent El Niño event (1997–98), larger individuals of the two island populations shrank more than smaller individuals. The scale of the shrinkage — up to 20% of body length — means that it cannot simply be explained by decreases in cartilage and connective tissue, which together make up only 10% of total body length. Apparently bone absorption accounts for much of the reduction.

  22. The fight against salt at Punta Espinoza: marine iguanas cormorants sea lions Marine Iguana

  23. salt crystals

  24. Flightless Cormorant drying its feathers at Punta Espinoza large flightless birds are common on islands, e.g. kiwi (New Zealand) extinct: Great auk (north Atlantic), dodo (Mauritius), solitaire (Reunion, Rodrigues), moa (New Zealand)

  25. California Sea Lions

  26. short-eared owl (flies)

  27. Flamingos in a salt marsh

  28. Pelicans

  29. Land iguana (Conolophus sp)

  30. Lava lizard doing pushups

  31. Territorial iguana chase

  32. Sally Lightfoot crab Resembles black crab of Hawaii’s Big Island

  33. stingless bee

  34. Pinnacle Rock on Bartolome: Excellent diving, lots of marine life

  35. The Physiology of Diving

  36. Emperor penguins Aptenodytesforsteri 550 m 22 min typical: 2-10 min, 50-500 m

  37. Elephant seal Mirounga leonina 1600 m 120 min typical: 20-30 min, 200-800 m

  38. Weddell seal Leptonychotes weddellii > 600 m 82 min

  39. Bottlenose dolphin Tursiops truncutus 210 m 5 min typical 30 m, 120 s

  40. Blue whale Balaenoptera musculus 300 m 50 min

  41. Sperm whale Physeter macrocephalus 3000 m 90 min

  42. In metabolism, electrons move around inside cells until they reach oxygen, which has the highest electron affinity of the biological elements Little Alberts 2-7 © Garland

  43. Emperor penguin Baikal seal Weddell seal In the absence of oxygen, glucose ® pyruvate and lactic acid. ~ 2 moles of ADP are converted to ATP. In the presence of oxygen, glucose + O2® H20 + CO2. ~ 24 moles of ADP are converted to ATP enzymes and carriers transfer 40% of the bond energy to high-energy phosphate bonds, in small steps. Diving mammals must store oxygen in order to conduct aerobic metabolism

  44. two oxygen-carrying heme proteins Diving mammals have much higher: blood volume hemoglobin concentration and especially myoglobin than other mammals. More than 80% of the oxygen is in the blood and muscle.

  45. two oxygen-carrying heme proteins Diving mammals have much higher: blood volume hemoglobin concentration and especially myoglobin than other mammals. More than 80% of the oxygen is in the blood and muscle.

  46. Crittercam (UC Santa Cruz) 35 cm batteries and computer detachable CCD camera 8 mm tape recorder lens float transmitter Ti or Al housing 900 nm LEDs fins Audio channels (1) accelerometer (2) microphone Transducers for pressure, water speed, and compass bearing are sampled once per second, and the data are stored on a PCMCIA card. A separate housing (17 cm long and 5.5 cm in diameter) for the gimbaled flux-gate compass is positioned behind the main housing and connected to it with a cable.

  47. Diving mammals glide much of the time

  48. Diving mammals save ~ 28% of their energy by gliding (plexiglas dome)

  49. Bottlenose dolphins save energy by slowing their heart rate during a dive

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