Cover Image

HARDBACK
$59.00



View/Hide Left Panel
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.

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 THE PRESENT 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



The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement