Turtles Diversification (Giant tortoises are not so slow)-

• Proc Natl Acad Sci U S A. 2004 Apr 27;101(17):6514-9. Epub 2004 Apr 14.
• Giant tortoises are not so slow: Rapid diversification and biogeographic consensus in the Galápagos
  Luciano B. Beheregaray, James P. Gibbs, Nathan Havill, Thomas H. Fritts, Jeffrey R. Powell and Adalgisa Caccone
• Giant tortoise populations (or taxa) showed distinct levels of diversity. Hypothetically, this disparity could be the result of a smaller evolutionary population size in arid and isolated islands (e.g., Española and San Cristóbal); as opposed to larger population sizes in younger islands, which have higher elevations and more ecological complexity (6, 13). Another potential cause is the unequal exploitation of tortoise populations by whalers in the 17th to 19th centuries. Whalers heavily collected tortoises in the more accessible islands such as Pinta, Española, and San Cristóbal, whereas exploitation was less intense or was nonexistent on islands with higher volcanoes (13).
• A previous phylogenetic study (11) indicates that one of the earliest migrations was from either San Cristóbal or Española to Santa Cruz (founding La Caseta population). Our estimate for this event of 2 Myr is consistent with geological evidence (Fig. 1) and demographic history: La Caseta has the highest [theta] (10 x 10-3) and is the only taxon with a mismatch distribution of a relatively old population with stable demography.

El Nino (El Nino Causes Harm to Wildlife in Pacific Islands)-

• Beeneet Kothari beeneetk@writeme.com | Wei Min Chin wmchin@pl.jaring.my | Robert Victor rvictor@suffolk.lib.ny.us for Thinkquest © 1998
• El Nino -> less plankton -> starving marine life (ex.: fish) that eat plankton -> starving other creatures (ex.: birds)that eat those creatures -> starving other creatures (other carnivores) that eat those creatures, etc.
  • also: starving and dying animals don't bode well with tourists
• El Nino -> lots more rain
  • arid -> lush
  • volcanic craters becoming lakes
  • rivers flowing where no water should be
• Waved albatrosses
  • hatched no eggs, but corrected with 1 good year
• Seals and Sea Lions-
  • During 1983, food shortages resulted in the death of almost all seals and sea lions under five years old, and of about 30% of the adult sea population
• Marine Iguanas-
  • El Nino -> different vegetation than usual -> less nutritious diet -> Many iguanas starved and nearly 90% of the 1982 iguana hatchlings died
• earliest recorded El Nino in 1567
  • named by Peruvian fishermen after the Christ child whose birthday was around the same date that El Nino peaks
• El Nino = warm Pacific Ocean; La Nina = cold Pacific
• linked to weather aberrations around the world

Return to Top

This web page created by Jill A. Rowehl

Email the author at ig3@mit.edu

Last Edited on Friday, 08-Oct-2004