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Magnetism inNatureAlejandro Ronda Morales

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Outline

What is magnetism?

Animal magnetism

Bees

Birds

Turtles

Cetaceans

Humans

Magnetotactic bacteria

Earths magnetism and extinctions

Applications

Conclusions

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What is magnetism?

Magnetic field

all region ofspace where actions areexerted on a magnetic polelocated at any point of it.

Produced by moving charges

Magnetic dipole differs fromgeographic dipole

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Animal magnetism

Bees Magnetite on their abdomen

Does not mean they use it

An experiment pointed thatinfluenced on their orientation

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Animal magnetism

Birds Orientation by detection

of magnetic field

An experiment with mespigeons pointed biggerimportance of magnetic than vision

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Animal magnetism

Turtles Orientation to birth place from

any point of the planetmapsense

Lute turtles detect inclination ofmagnetic field lines and intensity

Loggerhead turtle has the mostperfect animal compass

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Animal magnetism

Cetaceans Magnetite in their crania

Migrations following Eartmagnetic field lines

Strandings in coasts due orientation loss or geomadisturbances

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Animal magnetism

Humans Magnetite in brain tissue

Absorption of microwaveradiation; unknown effects ofmagnetic fields

Almost total loss of orientationby magnetic field

Experiment on orientation withstudentsImportance ofmagnetic field

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Magnetotactic bacteria

Aerotolerant aquatic bacte

Magnetosomesallow moalong magnetic field lines(magnetotaxis)

Synthesis of high purity cry

Magnetite (Fe3O4)

Greigite (Fe3S4)

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Magnetotactic bacteria

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Earths magnetism and extinctions

Possible relationship between

magnetic field inversions andextinctions

Silurian and Carboniferous:magnetically stablefew extinctions

Permian: magnetically instablemany extinctions

Cretaceous: no magnetic inversiongreater accumulation of organisms

Pliocene: last magnetic field inversionextinction ofAustralopithecusandHomo habilis

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Applications

Biomedicine

Diagnostic tool for detectumours, proteins, antibconjugation, etc.

Chronological dating

Shows magnetic remanelakes and oceans

Characterization ofpalaeoclimate andpalaeoenvironment

Rapid mineral replacem(Fe3+, iron sulphites)

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Applications

Astrobiology

Meteorite ALH84001

Carbide globules

Magnetite and greigite crystals

Polycyclic hydrocarbons

Evidence of primitive extra-

terrestrial life?

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Conclusions

Magnetism has been a very important factor for Earth, andtherefore life, since their origins.

Many possible applications, still under study, ranging frompalaeontological dating to clinical diagnosis and searching oterrestrial life.