1 Darwin C. 1859. The origin of species by means of natural selection. London: John Murray (1996 printing of the 2nd edition. Oxford: Oxford University Press).
2 Darwin C. 1875. Insectivorous plants. D. Appleton and Company, New York.
3 MacArthur, RH and EO Wilson. 1967. The Theory of Island Biogeography. Princeton University Press, Princeton NJ.
4 NOAA Ocean Service Education website. http://oceanservice.noaa.gov/education/kits/currents/05currents1.html
5 US Fish and Wildlife Service Climate Change website. http://www.fws.gov/home/climatechange/
6 Webb, SD. 1976. Mammalian faunal dynamics of the great American interchange. Paleobiology 2:220-234.