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Bioelectromagnetism

into UVC (0.10–0.28 μm), UVB (0.28–0.32 μm), and UVA (0.32–0.40 μm). Te IR is divided into IRA

(0.78–1.40 μm), IRB (1.40–3.00 μm), and IRC (3.00 μm–1 mm).

Tere are a variety of electromagnetic phenomena on earth. Since prehistoric times, biological sys­

tems have been exposed to the electromagnetic felds produced by the earth itself, atmospheric ions, and

electromagnetic felds associated with lightning discharge and solar activity. Terefore, it is presumed

that the evolution of life has been afected by these electromagnetic phenomena in various ways. In other

words, the question of what relationship exists between electromagnetic phenomena on earth and the

evolution of life has been a matter of great interest to both scientists and the general public. For example,

it has been reported that animals use actively the geomagnetic feld. Tese include magnetite-based

magnetotactic bacteria, the behavior of honeybees, and the migration of bird. It has also been reported

that diferent kinds of fsh use the Lorenzini organ to sense electric feld and control their behavior.

Electromagnetic felds are ubiquitous in earth’s atmosphere. Natural electromagnetic felds are consid­

ered to be one of the most important environmental factors.

Biological systems and their surrounding environment are closely related to each other. Te speci­

fcity of this relationship is said to be a major characteristic that sustains life. Among these environ­

ments, there has already been a great deal of research on the relationship between biological systems and

atmospheric pressure, temperature, humidity, visible light, UV, IR, radiation, and gravity. A number

of papers and books have been published. However, research on the relationship between the electro­

magnetic environment and biological systems has not progressed as much. Tis may be because we are

not considered to have electromagnetic receptors for light as we do for vision and sound as we do for

hearing.

In this chapter, we will discuss mainly how electromagnetic phenomena generated from atmospheric

activity relate to biological systems. In addition, we will focus on electroreception and magnetorecep­

tion. Tey have a connection with the change of electromagnetic felds in nature. Electroreception is the

ability to detect external electric feld. Magnetoreception is the ability to sense changes in a magnetic

feld to perceive direction, position, and navigation.

3.2 Atmospheric and Cosmic Environments

Earth was born as one planet in the solar system 4.6 billion years ago. Te primordial atmosphere con­

sisted of volcanic gases that erupted slowly from earth’s crust, and its main components are thought to

have been carbon dioxide, nitrogen, hydrogen, and water vapor. Nitrogen, which makes up 80% of air, is

contained in the amino acids that form proteins and the nucleic acids that form genes. Nitrogen is also

important for our respiration, making it a necessary element for life on earth.

Te synthesis of amino acids, the precursors for making proteins, is well known from Miller’s experi­

ments (Miller, 1953). A fask containing methane, ammonia, and water was heated to boiling, and the

resulting vapor was repeatedly discharged. As a result, organic substances including amino acids such

as glycine and alanine were produced. Miller’s experiment was based on the assumption of electrical

discharge in nature. Later, it was revealed that UV from the sun, radiation, and thermal energy can also

produce amino acids.

Afer hundreds of millions of years, the water vapor coagulated into water, which creates oceans

that covered about 70% of the earth’s surface. It transforms the earth into a watery planet. Te carbon

dioxide in the atmosphere was gradually replaced by oxygen through the photosynthetic action of cya­

nobacteria and green algae. Tus, it is believed that a water- and oxygen-rich global environment was

formed that enabled life to live.

On the ancient earth, intense UV poured down from the sky. Te UV light’s energy prevented the

emergence of life, so the frst life was born in the ocean, where the UV light could not reach. It has been

found in rocks about two billion years ago as fossils of cyanobacteria. Te presence of polymeric hydro­

carbons, which are also thought to be the decomposition products of chloroplasts, have been found in

the rocks. It suggests that photosynthesis was already present at that time. Tis increase in atmospheric