Tortugas-

• Kricher, John. 2002. Galapagos. Smithsonian Natural History Series. Washington & London. Smithsonian Institution Press
• on 9 or 10 of the islands
• male 600 pounds, female 110 lb; shell about 1 m
• current population ~15k
• Vice Gov. Nicholas Lawson- show me a shell of any giant tortoise, and i can tell you from which island it was collected
  • -> Origin of Species (helped persuade Darwin of it)
• the most important food plants for the saddlebacks (turtles)= the tree-sized cacti of genus Opuntia
  • also all eat endemic scalesias and guayavita, poison apple, and various lichens and the brommeliad Tillandsia insularis
• nest= 12'' deep and 8'' wide in soil
  • then sealed in and left behind
  • incubate from 4-8 months, then must find own way back to safe habitat (usually highlands turtles are born in lowlands)
• 2-3 decades to reach sexual maturity; can get as old as 150 yrs
• rats, dogs, and pigs are most threat bcs dig up nests and eat eggs
  • before man, the only nest predator was galapagos hawk
• Charles Darwin Research Station- has to dig up eggs and take care of infants until they're big enough to survive
• 1 clutch = 5-10 eggs; 1 clutch per yr; approx 80 yrs of breeding = a lot of turtles
  • but a lot of predators
• Turtles and the Galapagos Tomato (Lycopersicon cheesemanii)
  • eat fruit-> seed goes into stomach -> seed goes onto ground
  • turtle has removed coarse seed coat; seed is far away from parent; seed has lots of nutrients around it (from turtle)
• Turtles and finches-
  • finches sit on back -> turtle steps on plant -> insects fly out -> finch eats insect
  • finches touch back -> turtles extend neck -> finch eats ticks off of turtle (helps turtle)
• Iguanas-
  • largest ~4.5 ft including tail, 20 lbs
  • ~250k population
  • shrink up to 20% in a yr, usually bcs of El Nino, reversed by La Nina
  • land iguana found on Santa Fe
  • territories of land iguans = 33'-65' in diameter
• Snakes - eaten by hawks, usually less than 4', keep out of site
• a reappraisal of the aquatic specialzations of the galapagos marine iguana. evolution 31:891-97
• variation among pop of gala land iguanas: contrasts of phylogeny and ecology. bio jour of the linnean society 21: 185-207
• lots of birds eat out of the sea
  • some dive, some sit on top, some steal
  • penguins
  • flightless cormorant
  • ~10k pairs of blue-footed bobby
    • if there isn't enough food, then parents feed largest and ignore the others
  • frigatebirds- catch fish w/o getting wet
    • wingspan ~7'
  • sea animals have diurnal migration (go to surface at night, deep at day) so waved albatross feed at night
• ~140 species of birds in the galapagos
• 1982-83 el nino brought heavy rains to Daphne Major; turned from arid to verdant
  • finch and mocking bird pops skyrocketed
  • some birds reproduced at 3 months

galapagos. key environments. J.E Treherne 1984. Pergamon Press. Sydney.

• Weber, W.A. and S.R. Gradsein. "Lichens and Bryophytes."
  • orchilla moss- early 20th century collected by prisoners to make dies
  • lichens everywhere (1972)
• Porter, Ducan M. Endemism and Evolution in Terrestrial Plants
  • 229 endemic species, subspecies or varieties of vascular plants in the flora of the Galapagos
  • +312 natives = 541 indigenous vascular plants
• Eliasson, Uno. Native Climax Forests
  • vegetation changes w/ altitude and moisture from sea lvl to the top of the volcanoes ~1600m
    • moisture increases upwards
  • climax vegetation- vegetation that "has ceased to change and has reached an equilibrium with the environment"
  • Santa Cruz- forests of Scalesia pedunculata
    • mostly alt 200-750m
    • 5-15m in height, flat-topped, form a canopy

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This web page created by Jill A. Rowehl

Email the author at ig3@mit.edu

Last Edited on Monday, 11-Oct-2004