BIO 360 M8A1: Environmental Errors & Developmental Symbiosis

1. Environmental Errors             Strange things have been happening to our frogs for the last 20 years. Throughout the United States and South Canada, there is a reported increase in the number of deformed frogs living in the wild, wild deformity ranging from having “extra or missing limbs, missing or misplaced eyes, deformed jaws, malformed hearts and guts” (Gilbert, 2000), and the appearance of intersex frogs, those having “traits associated with both males and females, such as male frogs whose testes contain eggs” (Zimmer, 2011).             Several studies have been conducted to discover this phenomenon. On one hand, some studies show that the deformities are caused by a flatworm parasite called Riberoia ondatrae, on the other, there is the increase in human activity that may have exacerbated the problem. The Riberoia parasites or trematodes, which “infects several species of frogs just as they are developing their limbs, causing an assortment of defects such as no legs or even multiple legs that jut out at weird angles from the frogs’ bodies” (Dell’Amore, 2011).  While the Riberoia occurs naturally, research shows that human activities have caused their sudden prevalence.             Today, there is indication that even in lakes where there are no trematodes, several frogs are found to be deformed (Gilbert, 2000). It is not known what caused these deformities, but scientists say that the culprit may be pesticides. David Skelly, professor of ecology at the Yale School of Forestry & Environmental Studies, set out to discover the truth behind this claim, and his results are disturbing. According to Skelly, “the highest rates of deformities were not occurring in and around farmlands, but in cities and suburbs” and that the deformities “are most certainly not caused by a single chemical, but rather by a suite of substances” (Zimmer, 2011). Animals are more sensi...