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Notes from Research on
Monday, 11-Oct-2004
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
- 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
- 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