著者

西村 勉 毛利 佳年雄 福島 雅典

出版者

文部省科学研究費総合研究(B)「原始地球上における生命の起源に関する研究」班

雑誌

Viva origino (ISSN:09104003)

巻号頁・発行日

vol.36, no.1, pp.44-50, 2009

参考文献数

80

---

A number of ecological and evolutionary patterns or 'rules' dealing with body size have been proposed over the years, the most prominent being Bergmann's rule, Cope's rule, and Rensch's rule. The mechanisms underlying these patterns remain enigmatic. We focused on the relationship between magnetic field (MF) exposure and animal body size because Bergmann's rule holds that organisms tend to be larger at higher latitudes, where the geomagnetic field is more than two fold stronger than at lower latitudes. We researched the relationship between electromagnetic field (EMF) exposure and change in animal body weight using data in the literature. We conducted a meta-regression analysis to examine the impact of EMF exposure on animal weight as compared with the weight of unexposed controls. Meta-regression showed that EMF exposure had a statistically significant positive association with relative weight in males but not in females. The increase in body weight would explain Rensch's rule. The increase in the relative weights of males would explain Bergmann's and Cope's rules. Over successive generations, animals would gradually gain a considerable amount of body size if environmental MF and/or EMF become stronger over the course of time, which explains Cope's rule.