地磁场与生物的磁感应现象

两千多年前，人类发明了指南针用于辨别方向；而如今科学家们发现，很多动物也能利用体内的生物指南针感应磁场。笔者从磁场的产生入手，详细介绍了地磁场的性质和生物磁感应现象的产生。候鸟是最早被注意到能利用磁场导航，且目前已获得最多磁生物学研究结果的一类高等生物。大量的行为学实验证明，候鸟在长距离迁徙的过程中主要靠对地磁场的感应来确定方向，它们的大脑能记录下每一个特殊地点的磁特征，并据此找出到达各个目的地的飞行路线。不仅如此，部分鸟类的磁导航还有一定程度的蓝光依赖性、会受到异常磁场的干扰，这种现象可以用生物磁受体的磁铁矿的感应假说和化学感受假说来解释。很多生物，包括人类也都有与候鸟类似的磁受体，有些动物能用它们感受磁场并以此作为视觉和听觉的辅助，而其他生物的磁感应能力也许已经在进化的某个阶段被别的功能替代或是直接消失了。目前人们对于生物磁现象的研究才刚刚起步，还有很多未知的谜团等待我们去揭开，希望在不久的将来能看到更多令人惊讶的实验结果。

The effect of geomagnetism on biomagnetism

Many living things have an internal compass which can get the information of orientation from geomagnetism as well as people using a real compass. We start from the generation of magnetism, and then introduce the property of geomagnetism and biological magnetic induction. Birds having migratory behavior are the kinds of Vertebrata which has firstly been found to have a remarkable ability of perceiving the Earth’s magnetic field. Research results show that, migratory birds can perceive and remember the magnetic features of the place they have ever been and get route direction from them. In addition, some of the avian compass have a dependence on blue light, and may be disrupted by anomalous magnetic field. Such phenomenon can be explained by two prevalent modes of magneto-reception, the magnetite-based magneto-reception and chemical magneto-reception, either or both of them could be found in organisms that have the so-called sixth sensation. Many other creatures, including human beings, have the same kind of magneto-receptors as well. However, not all of them use the sixth sensation as a visual or auditory aid, during the long term evolution this ability may be disappeared or replaced by something else. This review also focuses on progress in biological magnetic phenomena and biological perspective of hypo-magnetic field; they are expected to elicit more amazing results.