<?xml version="1.0" encoding="UTF-8" standalone="yes"?><oembed><version><![CDATA[1.0]]></version><provider_name><![CDATA[Azimuth]]></provider_name><provider_url><![CDATA[https://johncarlosbaez.wordpress.com]]></provider_url><author_name><![CDATA[John Baez]]></author_name><author_url><![CDATA[https://johncarlosbaez.wordpress.com/author/johncarlosbaez/]]></author_url><title><![CDATA[Biodiversity, Entropy and&nbsp;Thermodynamics]]></title><type><![CDATA[link]]></type><html><![CDATA[<p>&nbsp;</p>
<p><img width="450" src="https://i2.wp.com/math.ucr.edu/home/baez/bio_info/408px-Forest_fruits_from_Barro_Colorado.jpg" /></p>
<p>I&#8217;m giving a short 30-minute talk at a workshop on <a href="https://johncarlosbaez.wordpress.com/2014/01/31/bio-inspired-information-theory/"> Biological and Bio-Inspired Information Theory</a> at the Banff International Research Institute.</p>
<p>I&#8217;ll say more about the workshop later, but here&#8217;s my talk, in PDF and video form:</p>
<p>&bull; <a href="http://math.ucr.edu/home/baez/bio_info/">Biodiversity, entropy and thermodynamics</a>.</p>
<p>Most of the people at this workshop study neurobiology and cell signalling, not evolutionary game theory or biodiversity.  So, the talk is just a quick intro to some things we&#8217;ve seen before here.  Starting from scratch, I derive the Lotka&#8211;Volterra equation describing how the distribution of organisms of different species changes with time.  Then I use it to prove a version of the Second Law of Thermodynamics.</p>
<p>This law says that if there is a &#8216;dominant distribution&#8217;&#8212;a distribution of species whose mean fitness is at least as great as that of any population it finds itself amidst&#8212;then as time passes, the information <i>any</i> population has &#8216;left to learn&#8217; always decreases!</p>
<p>Of course reality is more complicated, but this result is a good start.</p>
<p>This was proved by Siavash Shahshahani in 1979.  For more, see:</p>
<p>&bull; Lou Jost, <a href="http://www.loujost.com/Statistics%20and%20Physics/Diversity%20and%20Similarity/JostEntropy%20AndDiversity.pdf">Entropy and diversity</a>.</p>
<p>&bull; Marc Harper, <a href="http://arxiv.org/abs/0911.1763">The replicator equation as an inference dynamic</a>.</p>
<p>&bull; Marc Harper, <a href="http://arxiv.org/abs/0911.1383">Information geometry and evolutionary game theory</a>.</p>
<p>and <a href="http://arxiv.org/find/math/1/au:+Harper\_M/0/1/0/all/0/1">more recent papers by Harper</a>.</p>
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