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Depends on the article you read :) This one sounds much scarier: http://blogs.discovermagazine.com/d-brief/2014/06/10/earths-magnetic-flips-may-triggered-mass-e

by geetee 12y ago

Depends on the article you read :) This one sounds much scarier: http://blogs.discovermagazine.com/d-brief/2014/06/10/earths-magnetic-flips-may-triggered-mass-extinctions/#.U8WdIvnHsbY http://blogs.discovermagazine.com/d-brief/2014/06/10/earths-... I wonder how it will affect animals that migrate...

dm2 12y ago
It sounds like a relatively gradual process, animals might be able to adapt quickly, they've done it before.
- pbhjpbhj 12y ago
  Gradual how? If there's no overall magnetic moment then surely navigation on magnetic field sensing organs will simply fail, if it switches/moves - even gradually - and stays the same strength then the animal likely ends up in entirely the wrong place with the wrong foodstuffs and climate. Can't see that either of those "gradual processes" is going to work well. Certainly the magnetic field has flipped before but do we know that animals that use magnetism for migratory guidance were able to "adapt quickly". Can you walk us through the evidence?
  - jdmichal 12y ago
    You're assuming that this is the only method of navigation they have, instead of it being one tool within their navigation tool belt. Also, I'm sure magnetic sensory organs have some natural error to them that they are constantly re-calibrating for. If the reversal happens within the bounds of natural error and recalibration, then I suspect they would have little trouble adapting.
    - thret 12y ago
      Correct, animals such as homing pigeons primarily rely on sight and landmarks. There are no known animals that exclusively use magnetic fields to navigate.
      - dm2 12y ago
        The Monarch Butterfly uses it when the sun isn't available: http://en.wikipedia.org/wiki/Monarch_butterfly#Migratory_Theory_Mechanisms http://en.wikipedia.org/wiki/Monarch_butterfly#Migratory_The... Apparently it "sees" the magnetic fields, but it also relies on the sun. I don't think it's been studied if it can reorient itself at birth if the poles are switched or if it's "hardcoded".
      - adrianN 12y ago
        There are some bacteria https://en.wikipedia.org/wiki/Magnetotactic_bacteria https://en.wikipedia.org/wiki/Magnetotactic_bacteria
        thret 12y ago
        This is a good point, although I submit that the magnetic direction is irrelevant for their purpose.
      - pbhjpbhj 12y ago
        I wonder how they manage when flying at night. Do those birds that are more capable night-flyers have superior magnetic senses?

by geetee 12y ago

dm2 12y ago

It sounds like a relatively gradual process, animals might be able to adapt quickly, they've done it before.

pbhjpbhj 12y ago
Gradual how? If there's no overall magnetic moment then surely navigation on magnetic field sensing organs will simply fail, if it switches/moves - even gradually - and stays the same strength then the animal likely ends up in entirely the wrong place with the wrong foodstuffs and climate. Can't see that either of those "gradual processes" is going to work well. Certainly the magnetic field has flipped before but do we know that animals that use magnetism for migratory guidance were able to "adapt quickly". Can you walk us through the evidence?
- jdmichal 12y ago
  You're assuming that this is the only method of navigation they have, instead of it being one tool within their navigation tool belt. Also, I'm sure magnetic sensory organs have some natural error to them that they are constantly re-calibrating for. If the reversal happens within the bounds of natural error and recalibration, then I suspect they would have little trouble adapting.
  - thret 12y ago
    Correct, animals such as homing pigeons primarily rely on sight and landmarks. There are no known animals that exclusively use magnetic fields to navigate.
    - dm2 12y ago
      The Monarch Butterfly uses it when the sun isn't available: http://en.wikipedia.org/wiki/Monarch_butterfly#Migratory_Theory_Mechanisms http://en.wikipedia.org/wiki/Monarch_butterfly#Migratory_The... Apparently it "sees" the magnetic fields, but it also relies on the sun. I don't think it's been studied if it can reorient itself at birth if the poles are switched or if it's "hardcoded".
    - adrianN 12y ago
      There are some bacteria https://en.wikipedia.org/wiki/Magnetotactic_bacteria https://en.wikipedia.org/wiki/Magnetotactic_bacteria
      - thret 12y ago
        This is a good point, although I submit that the magnetic direction is irrelevant for their purpose.
    - pbhjpbhj 12y ago
      I wonder how they manage when flying at night. Do those birds that are more capable night-flyers have superior magnetic senses?