Posts tagged ‘second law’

June 22, 2011

Fisher on Thermodynamics and Evolution

by Lucas Wilkins

I’ve been reading Ronald Fishers book: The Genetical Theory of Natural Selection, which is now publicly available. I was a little surprised to find he wrote a page or two on thermodynamics and entropy in evolution, here it is, verbatim, with a couple of comments on the numbered points. First though, his definition, in words, of the fundamental theorum of Natural Selection:

The rate of increase in fitness of any organism at any time is equal to its genetic variance at that time.

with that in mind…

May 9, 2011

Is the second law of thermodynamics connected to the expansion of the universe?

by Nathaniel Virgo

This is just a bit of idle wondering, another little bit of amateur cosmology from someone who should probably know better. The question I’m asking myself today is, is the second law of thermodynamics connected to the expansion of the universe?

April 15, 2011

Entropy is Not Disorder

by Nathaniel Virgo

The second law of thermodynamics — the law of entropy — is a fascinating thing.  It’s the law that makes the past different from the future; it’s the law that predicts an effective end to the Universe, yet it’s the law that makes life possible.  It’s also a deeply mysterious law.  It took well over a century for true meaning of entropy to be understood (in fact arguments on the subject still rage today), and we still don’t understand, on a cosmological level, exactly why it was so low in the past.

One of the things that’s often said about entropy is that it means “disorder”.  This post is about that idea.  It’s worth discussing for two reasons: firstly, it’s wrong.  It’s close to the truth, in the same sort of way that a spectrum is close to a rainbow, but not the same.  Secondly, the real truth is much more interesting.

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