TNRTB Archive – Retained for reference information
A team of European and American conservation biologists has developed the most powerful and comprehensive field evidence to date for a major tenet of RTB’s speciation model. RTB’s model posits that large-body-sized species manifest a high probability for rapid extinction and a very low probability for speciation and, thus, are not candidates for natural evolution. The biologists’ study of 4,000 land mammal species spanning a body mass range from 2 grams to 4,000 kilograms showed that the slope of extinction risk against six established predictors of extinction becomes steeper with increasing body mass. In particular, a sharp increase in extinction risk occurs at a body mass of three kilograms. Above this size body mass “extinction risk begins to be compounded by the cumulative effects of multiple threatening factors,” the authors note. The team’s study establishes that land mammals with large body sizes possess extinction rates that are orders of magnitude larger than the most optimistic speciation rates. Consequently, mammals with large body sizes cannot be the product of natural process evolution.
- Marcel Cardillo et al., “Multiple Causes of High Extinction Risk in Large Mammal Species,” Science 309 (2005): 1239-41.
- Related Resource
- Hugh Ross, “The Faint Sun Paradox”