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

Geography 13 large islands (>10 km2), 6 smaller islands of 1-2 km2 Many islets, rocks Total land area: ~8,000 km2 (SC: ~77,700 km2) Mainland Ecuador ~960 km to east Costa Rica ~1100 km away

Geology http://alpha.dickinson.edu/departments/geol/gal_2003.htm Fernandina 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/05galapagos/background/hotspots/media/Galapagos_IS_Topo_600.jpg

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

Uplifted areas may include fossil-bearing (calcareous) rocks Baltra Island http://www.geo.cornell.edu/geology/GalapagosWWW/SantaCruz.html

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

Climate patterns http://www.galapagosonline.com/Galapagos_Natural_History/Oceanography/ClimateWeather/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_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 http://op2.lb.nagasaki-u.ac.jp/galapagos/en/plant1.html

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

Finches

Mockingbirds http://oikos.villanova.edu/Nesomimus/melanotis.html San Cristóbal Mockingbird Nesomimus melanotis 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