The Galpagos Islands Part 1 Environmental Setting BIO

The Galápagos Islands: Part 1 - Environmental Setting BIO 53 Fall 2007

Geography 13 large islands (>10 km 2), 6 smaller islands of 1 -2 km 2 Many islets, rocks Total land area: ~8, 000 km 2 (SC: ~77, 700 km 2)

Geology http: //alpha. dickinson. edu/departments/geol/gal_2003. htm

Cocos Plate Galápagos Pacific Plate Nazca Plate http: //commons. wikimedia. org/wiki/Image: Nazca_Plate_map-fr. png

The Galápagos Platform http: //oceanexplorer. noaa. gov/explorations/05 galapagos/background/hotspots/media/Galapagos_IS_Topo_600. jp g

Hot Spots and Volcanic Island Formation http: //www. tulane. edu/~sanelson/images/hotspot. gif

Lava flows (basalt) http: //alpha. dickinson. edu/departments/geol/gal_2003. htm

Eroding tuff formation http: //www. calstatela. edu/dept/geology/Hot. Spots. htm

Uplifted areas may include fossil-bearing (calcareous) rocks Baltra Island http: //www. geo. cornell. edu/geology/Galapagos. WWW/Santa. Cruz. html

Climate of the Galápagos http: //www. junglephotos. com/galapagos/gscenery/weather/climate. shtml

Climate patterns http: //www. galapagosonline. com/Galapagos_Natural_History/Oceanography/Climate. Weather/Climate. html

Climate patterns

Climate patterns

The Galápagos Islands: Part 2 – Darwin’s visit Darwin’s voyage on the H. M. S. Beagle (1831 -1836)

Charles Darwin (1809 - 1882) Darwin at age 31 (1840 portrait by Richmond)

Jean Baptist de Lamarck : (1744 -1829) • Belief in gradual changes in organisms over long time periods • Recognized the environment as an important influence on evolution: Inheritance of acquired characters • Published theory in 1809 http: //necsi. org/projects/evolution/lamarck/lamarck_lamarck. html

Charles Lyell: author of Principles of Geology (1830) • Proponent of uniformitarianism • Slow, steady, gradual changes have shaped earth surface • Earth at least millions (not thousands) of years old http: //www. mnsu. edu/emuseum/information/biography/klmno/lyell_charles. html

Figure 23. 1 Darwin and the Voyage of the Beagle (Part 2)

Sep. 17: Chatham (San Cristobal)

Arid lowlands and tortoises http: //www. mountaininterval. org/photos/galapagos/highlights/pages/10 -roll/25 -san-cristobal-tortoise. html

Sep. 23: Charles (Floreana)

Moist Uplands http: //www. unc. edu/depts/geog/lcsal/new/galapagos/images/photos. htm

Sep. 29: Albemarle (Isabela)

Iguanas

Oct. 8: James (Santiago/San Salvador)

Moist Uplands

Other observations 25 of 26 land bird species unique to the islands • Galapagos Dove

Finches

Mockingbirds http: //oikos. villanova. edu/Nesomimus/melanotis. html

Tortoises Saddleback Dome-shaped

Plants: number of species confined to the islands • • James: 38 of 71 Albemarle: 26 of 46 Chatham: 16 of 32 Charles: 29 of 68 • in modern terms: high levels of endemism