On Sat, Sep 27, 2014 at 2:39 PM, Tim Tyler via AGI <[email protected]> wrote: > Of course in real-world evolution, there are other ways of > getting useful information into the genome. You can choose > sexual partners from a pool of prospective mates. Or you can > kill 99% of the population and breed from the remaining 1%. > Or, you can insert information directly into the genome, > using genetic engineering.
Good point. Considering epigenetic transfer, writing the software equivalent to our DNA would be more expensive. However, this additional knowledge cannot contribute to reproductive fitness. The actual limit is log n bits per generation, where n is the number of offspring in a steady state population. > There's no known speed limit on evolution. Yes there is. Copying one bit of information in any form including DNA requires at least kT ln 2 energy, or about 3 x 10^-21 J at room temperature. Growth and maintenance also require energy. Your body performs 10^25 DNA base copy operations, 10^28 RNA and amino acid operations, and 10^26 synapse operations in your lifetime, subject to the same energy requirements. The speed of evolution is limited by the 3.8 x 10^26 W of energy from the sun, of which only 10^-9 reaches the Earth, and only 1% of that is converted to chemical energy by photosynthesis. > The faster we > can copy, and the larger the size of the populations > involved, the faster evolution can progress. There > are thought to be limits on copying speed (associated > with the Bekenstein Bound) - though these seem far off. The Bekenstein bound limits entropy within a region of space. It is 4 nats (4/ln 2 bits) per Planck area of the enclosing boundary. The limit is reached only for a black hole. For the Hubble radius, it is 2.95 x 10^122 bits. If you believe Moore's Law, that's 500 years away. Of course we will run into speed of light delays first as we try to collect computing resources from outside our solar system. > However, we don't know of a limit on population size. A Dyson sphere would collect enough energy to support 10^24 humans at 100 watts each assuming 30% collection efficiency. This population would have a mass close to that of the Earth, and therefore would require mining the outer planets for nutrients. -- -- Matt Mahoney, [email protected] ------------------------------------------- AGI Archives: https://www.listbox.com/member/archive/303/=now RSS Feed: https://www.listbox.com/member/archive/rss/303/21088071-f452e424 Modify Your Subscription: https://www.listbox.com/member/?member_id=21088071&id_secret=21088071-58d57657 Powered by Listbox: http://www.listbox.com
