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8/13/2019 Magnetism in Nature
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Magnetism inNatureAlejandro Ronda Morales
8/13/2019 Magnetism in Nature
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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.