. "2 Are We in the Midst of the Sixth Mass Extinction? A View from the World of Amphibians--DAVID B. WAKE and VANCE T. VREDENBURG." In the Light of Evolution, Volume II: Biodiversity and Extinction. Washington, DC: The National Academies Press, 2008.
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In the Light of Evolution: Volume II—Biodiversity and Extinction
FIGURE 2.5 Distribution of species of amphibians discovered and named during the period 2004–2007. Bar indicates number of new species per country. (Inset) Baseline world map. Visualization is based on density-equalizing cartograms prepared by M. Koo.
salamanders, and caecilians will survive the current extinction event on their own or with help, even as their ancestors survived the four preceding mass extinctions.
WHAT IS THE PRINCIPAL CAUSE OF THEPRESENT EXTINCTION SPASM?
Human activities are associated directly or indirectly with nearly every aspect of the current extinction spasm. The sheer magnitude of the human population has profound implications because of the demands placed on the environment. Population growth, which has increased so dramatically since industrialization, is connected to nearly every aspect of the current extinction event. Amphibians may be taken as a case study for terrestrial organisms. They have been severely impacted by habitat modification and destruction, which frequently has been accompanied by use of fertilizers and pesticides (Hayes et al., 2002). In addition, many other pollutants that have negative effects on amphibians are byproducts of human activities. Humans have been direct or indirect agents for the introduction of exotic organisms. Furthermore, with the expansion of human populations into