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Is learning a characteristic of all organisms?

  1. Dec 18, 2011 #1
    Just heard someone make that claim...seems a little bit, well, stupid.

    Do all organisms possess the ability to learn new things? I would argue that moss on a rock, any plant (note: naturally responding to environmental change is not learning) etc. do not learn..
     
  2. jcsd
  3. Dec 18, 2011 #2

    apeiron

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    It of course depends whether you define learning narrowly or broadly. A general mid-range definition would be "modification of behaviour due to experience".

    If you are looking for a sharp dividing line, then not having a central nervous system would seem to rule out the plant kingdom.

    Except plants may then have some level of integrative memory in the form of signal-transduction networks....

     
  4. Dec 18, 2011 #3

    atyy

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    Phenotypic plasticity
    http://jeb.biologists.org/content/209/12/i.full

    There are different sorts of learning like associative/non-associative etc and different sorts of memory like declarative/procedural etc. so you'd probably like to refine your question according to one of those taxonomies. apeiron's turf, I believe, since I think he was a neural networks guy.
     
    Last edited: Dec 19, 2011
  5. Dec 19, 2011 #4
    Building upon what apeiron and atyy said, I would say that a basic principle in cellular signalling is that signalling pathways have evolved to respond to changes in stimuli rather than their absolute level. This acts like an effective filtering mechanism you could say, which gives accurate responses to stimuli and ignores background noise. Every time a receptor is activated it needs to be reset in order to accept new signals. Repeated cycles can cause them to desensitize over time. Cells usually accomplish this by blocking out receptors by special molecules or phosphorylation, for example repeated stimulation of β-androgenic receptor causes it to bind with β-Arrestin and prevents it from binding to hormones. This might very well be called molecular or cellular learning.

    You can even extend this to the immune system with their memory B cells and although that wouldn't be considered an organism.
     
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