However, the compass used by homo sapiens may not be the only compass which exists, composed of magnetite: a natural compass has been discovered in several zoological species where deposits of magnetite appear to be the basis of the ability, also found in homo sapiens, though with no apparent use thus far. In essence, living organisms may be classified as living compasses.

Since times of the ancient Greek civilization, it has been observed that magnetite, also known commonly as lodestone, attracts metallic objects, which may be used as a compass to navigate, as it is sensitive to the earth’s magnetic fields. A magnetic field may also be addressed as the region in space within which magnetic force functions, the field flowing from north pole to south as in a bar magnet (SPH4). Magnetic fields may be attractive, which attracts materials to one another, or repulsive, where materials repel one another. The magnetic field of the earth is the result from movement of melted material within the earth’s core, which allows for the movement of magnetic north and south and a field which reverses, as has been discovered to have occurred many times. At present, it has been observed that the magnetic field may be in the process of reversal at this point, however the changes are slight in relation to our perception of rate.

Magnetic fields may be created by any wire which conducts current, such as a wire used to connect computers to the wall outlet or to each other, or an object such as a computer itself, as states the Principle of Electromagnetism. Artificial applications of electromagnetism include the lifting magnet as in automobile destruction, the telegraph for communication, a switch or relay, emergency lights, burglar systems, the door bell, the motor, and the moving coil galvanometer (SPH4).

The earth has possessed a magnetic field for millennia since its formation which has changed in orientation, the study of which is known as paleomagnetism. Since the invention of technology which has allowed for such study, it has been discovered that there have existed several field reversals, all of which have been found recorded in what was once hot lava. Lava is known heat rock to a very high temperature where crystals in the lava particles are organized haphazardly. As cooling rock approaches the a state known as the Curie point, the haphazard crystals begin to align with the earth’s magnetic field- if the temperature decreases to a point found proceeding the Curie point, the magnetic alignment is frozen within the rock. Marine samples from the Atlantic ocean provide the information of the past as discovered by J. Tuzo Wilson: the rift found in the Atlantic is as a dividing line between two moving plates, providing for the symmetry found in field reversals across the mid-Atlantic ridge, a form of geological recorder of past events (SPH4).

Biomagnetism

Several processes in the zoological body are based on electrical activities throughout the neural system and tissues, which generates an electromagnetic field around the body. One type of magnetism has been called "animal magnetism", a force which, as it has been alleged, is produced in animal tissues and may pass from one body to another with or without true contact, as asserted by Mesmer in 1775 (40). Although such may exist, this work intends to address a different form of magnetism, as found within organisms to be employed as a navigational aid or as a way to merely store iron in cells.

As has been discovered in a variety of zoological specimens, there is present in many species crystals of magnetite, a black, ferromagnetic mineral form of Iron (II) Iron (III) Oxide (Fe₃O₄) which crystallizes in isomeric system (or, all crystals have crystallographic axes of equal length, situated 90 to each other)(B). It is one of the major compounds of iron which is strongly magnetic and some are natural magnets, or lodestone. Its ferromagnetic crystals interacting more strongly with external magnetic forces than other magnetic materials which are diamagnetic or paramagnetic and is only generated by cells when needed (B). The discovery of such a biogenic substance may be accounted for as a major achievement towards the comprehension of how some living organisms may detect the earth’s magnetic field, found to be organized into linear, membrane-bound chains of a length of only a few micrometers ( m), possessing up to eighty crystals per chain, allowing for the analogy of a bar magnet to be employed (B).

Bundles of magnetite have been discovered in the brain of zoological specimens the navigate by compass direction, such as birds, bees, fish, amidst others, however it was also found to exist in the human brain in 1992: human brain tissue extracts taken from membranes surrounding the brain and spinal chord (including clustering in the region of the brain where the nose joins the skull) contained crystals of magnetite, although the function of magnetite within humans is still an enigma as it is not sure as to whether humans may detect magnetic fields or not (38). However, it is known that single-domain magnetite crystals, as found in the body, experience a torque when subjected to exposure to static and low-frequency magnetic fields, implying that perhaps, the magnetic fields generated by power lines, cell phones, computers, audio and visual apparatus’- including stereos and televisions- may be affecting the living body at this very point, human or otherwise (38). However, it has been found that some homo sapiens are sensitive to changes in weak magnetic fields, which some claim may also explain the ability known as extrasensory perception (ESP), as the ability of the body to transmit and receive faint electromagnetic signals from other bodies (O).

Biomagnetism: Applications

Research into how animals use earth’s magnetic fields to navigate travels of varying distances is continuous, as it is not entirely proven how animals detect the magnetic field, particularly since migrational species of birds may use celestial and light cues, where the magnetic field detection is regarded as a "backup" (Bahr3 152/153). It is, however, believed possible that there exists two forms of magnetic receptors found in zoological species which allows for the use of the field: there are iron-based receptors and light activated (A).

Iron-based receptors provide for an organisms to distinguish how far north or south they may be from any given latitude, although the determination of longitude poses, still, a confusion. Magnetite constitutes this ability, which floats in the receptor cells, making contact with the sides of the cells. In detecting the movement of the particles, the receptor detects the strength of the magnetic field, which strengthens as poles are neared (A). Light-activated receptors, however, found in the brain’s pineal gland, act very much like a simple compass, indicating only the general direction of north, yet mostly during the day. It is assumed that both systems may be utilized together to increase navigational skills, where one is used for direction and the other for position (A). In the case of some birds, it has been found that when the head is moved, impulses in the surrounding nerves are triggered and the packages of magnetite are activated, a response to the earth’s magnetic field (38).

Magnetite and navigational abilities accompanied by the [possible] use of magnetic fields have been discovered in a variety of organisms: homing and carrier pigeons to find their way home; lobsters; Eastern red-spotted newts and other newts; sea turtles, including the Loggerhead; birds, including Bobolinks, used particularly for migrational purposes; sea slugs, perhaps in the search for food; rats; frogs; humans; honeybees; the African elephant-nose fish, who generate and detect magnetic fields; the platypus; spiny anteaters; star-nosed moles; fish, such as the tuna; butterflies; dolphins; and magnetic-sensitive bacteria have been determined as employers of magnetic fields, or possible employers, as in the case of humans (A, 38). Loggerhead sea turtles may use magnetic sense to stay within the warm regions of the North Atlantic before returning to home beaches where newts may use magnetic sense to escape predators across a pond, by magnetically navigating to their home pond from a distance less than 12.9 km (approximately 8.0 miles) after journeying through the forest floor in the adolescent stage of development (A).

It is, however, possible for magnetite to occur within an organism without use as a magnetic compass: magnetite may exist in other cells, used for other purposes, such as some snails, who use magnetite on the tongue to scrape up food (A).

Summary

Although not expected of living organisms, it has been discovered that some animals may possess a natural compass in the form of the iron oxide, magnetite, found in the cells of the brain (or otherwise, for different purposes) which may be used in migration or general navigation. Homo sapiens have been observed to possess magnetite, although no true reason has occurred for its use. It has been discovered, however, that magnetic fields may make impact upon the living body, where even weak electromagnetic fields may accelerate the development and growth of some forms of cancers (O). As Soviet scientists have discovered, severe attacks of glaucoma caused by an increase of fluid present inside the eyeball have had a tendency to occur during sudden manipulations of the earth’s magnetic field, as created when flares from the surface of the sun transmit gusts of magnetized particles into the planet’s atmosphere (O). American scientists have observed the changes in psychiatric patients, reporting that patients have been known to turn suicidal with field manipulations of the earth (O). However, it is known that by mapping the magnetic patterns of healthy brains, the area of brain function may be derive, and that the magnetic fields of the brain are strongest when the body is asleep. Due to this discovery, a particular sleeping position is suggested: sleep with the head towards the east, legs towards the west in order to allow magnetic fields to run from the head through to the toes as the earths field is neutral, but the magnetic fields of the sun and moon are also affecting bodies on earth, which seem to play no apparent role in life of living organisms however still may impact (O).