May 7th, 2012

the bacterium Magnetospirillum magneticum

These naturally magnetic microorganisms usually live in aquatic environments such as ponds and lakes, below the surface where oxygen is scarce.

They swim following the Earth’s magnetic field lines, aligning in the magnetic field like compass needles, in search of preferred oxygen concentrations.

When the bacteria ingest iron, proteins inside their bodies interact with it to produce tiny crystals of the mineral magnetite, the most magnetic mineral on Earth.

Having studied the way the microbes collect, shape and position these nano-magnets inside themselves, the researchers copied the method and applied it outside the bacteria, effectively “growing” magnets that could in future help to build hard drives.

“We are quickly reaching the limits of traditional electronic manufacturing as computer components get smaller,” said lead researcher Dr Sarah Staniland of the University of Leeds.

“The machines we’ve traditionally used to build them are clumsy at such small scales.

“Nature has provided us with the perfect tool to [deal with] this problem.”

More: BBC Technology

September 21st, 2010

neato magneto

The European Robin doesn’t need a map. Photo: Ernst Vickne

Wiki:

Magnetoception (or magnetoreception) is the ability to detect a magnetic field to perceive direction, altitude or location.

Wikipedia notes that biological stores of the magnetic mineral Magnetite are present in many animals. This mineral is what enables, through various different mechanisms, an organic ability to use Earth’s magnetic field for the purposes of navigation.

One of several fascinating examples:

In 2008, a research team led by Hynek Burda using Google Earth accidentally discovered that magnetic fields affect the body orientation of cows and deer during grazing or resting. In a followup study in 2009, Burda and Sabine Begall observed that magnetic fields generated by power lines disrupted the orientation of cows from the Earth’s magnetic field.

According to the same article, there are even vestigial amounts of Magnetite in we humans, which might suggest that we once relied on this system. Maybe there came a time when our increased intelligence made the ingenious mechanism of megnetoception obsolete.

Based on my experience negotiating large metropolitan areas, I estimate that my stores of Magnetite are very vestigial indeed.

Magnetoception @ wikipedia

January 31st, 2013

infrasound pigeon navigation

He said: “The way birds navigate is that they use a compass and they use a map. The compass is usually the position of the Sun or the Earth’s magnetic field, but the map has been unknown for decades.

“I have found they are using sound as their map… and this will tell them where they are relative to their home.”

The pigeons, he said, use “infrasound”, which is an extremely low-frequency sound that is below the range of human hearing.

He explained: “The sound originates in the ocean. Waves in the deep ocean are interfering and they create sound in both the atmosphere and the Earth. You can pick this energy up anywhere on Earth, in the centre of a continent even.”

He believes that when the birds are at their unfamiliar release site, they listen for the signature of the infrasound signal from their home – and then use this to find their bearings.

However, infrasound can be affected by changes in the atmosphere.

BBC. (Related posts)

October 15th, 2010

electroreception

Platypuses can detect their prey using electrodetectors located in their bills:

The Platypus can determine the direction of an electric source, perhaps by comparing differences in signal strength across the sheet of electroreceptors. This would explain the characteristic side-to-side motion of the animal’s head while hunting. The cortical convergence of electrosensory and tactile inputs suggests a mechanism for determining the distance of prey items which, when they move, emit both electrical signals and mechanical pressure pulses: the difference between the times of arrival of the two signals would allow computation of distance.

The Platypus feeds by neither sight nor smell, closing its eyes, ears, and nose each time it dives. Rather, when it digs in the bottom of streams with its bill, its electroreceptors detect tiny electrical currents generated by muscular contractions of its prey, so enabling it to distinguish between animate and inanimate objects, which continuously stimulate its mechanoreceptors. Experiments have shown that the Platypus will even react to an “artificial shrimp” if a small electrical current is passed through it.

Wikipedia.

See also: Magnetoception.






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