CMU Artificial Intelligence Repository
 
   
   
   
   
  
Tierra: Evolution of digital organisms
areas/alife/systems/tierra/
Tierra is an artificial life system for studying the evolution of
digital organisms. Tierra consists of a virtual computer and its
operating system, whose architecture has been designed in such a way
that the executable machine codes are evolvable.  This means that the
machine code can be mutated (by flipping bits at random) or recombined
(by swapping segments of code between algorithms), and the resulting
code remains functional enough of the time for natural (or presumably
artificial) selection to be able to improve the code over time.
This system results in the production of synthetic organisms based on
a computer metaphor of organic life in which CPU time is the
``energy'' resource and memory is the ``material'' resource.  Memory
is organized into informational patterns that exploit CPU time for
self-replication.  Mutation generates new forms, and evolution
proceeds by natural selection as different genotypes compete for CPU
time and memory space. Diverse ecological communities have emerged.
Ready-made DOS executables may be purchased from 
   Virtual Life                Virtual Life
   25631 Jorgensen Road        PO Box 625
   Newman, CA 95360            Newark, DE 19715
for $65 on DOS disks.
[Virtual Life will also be offering a PC version of Karl Sims'
evolutionary art system, called Darwinian Art.]
See Also: 
   areas/alife/systems/psoup/
Origin:   
   tierra.slhs.udel.edu:/tierra/ [128.175.41.34]
   life.slhs.udel.edu:/tierra/   [128.175.41.33]
Version:      4.0 (16-MAR-94)
Requires:     C
Ports:        UNIX, MSDOS
Copying:      Copyright (c) 1990-92 Thomas S. Ray
              Distribution of source code and documentation permitted.
              Distribution of binaries for any platform is not permitted.
              (See the file license.h for details.)
              Please contribute an amount to "Virtual Life" (see
              addresses above) that represents the program's worth to you.
CD-ROM:       Prime Time Freeware for AI, Issue 1-1
Bug Reports:  tierra-bug@life.slhs.udel.edu
Mailing List: To be added to either the
                 tierra-announce (official announcements only) or
                 tierra-digest (moderated discussion plus announcements)
              mailing lists, send mail to tierra-request@life.slhs.udel.edu.
Author(s):    Tom Ray  or 
              [Tom's Current email is ray@hip.atr.co.jp; mail to
              ray@udel.edu will be forwarded.]
              
              Daniel Pirone .
              Tom Uffner 
              Marc Cygnus
Contact:      Tom Ray  or 
              University of Delaware
              School of Life & Health Sciences
              Newark, Delaware  19716
              Fax: 302-451-2281
              Tel: 302-451-2753
Keywords:
   Artificial Life, Authors!Ray, Evolution of Digital Organisms, 
   Tierra, Virtual Life
Contains:
   Tierra data.
   overview/    Overview 1.0 is an X11R4 graphics tool for visualizing
   doc/         Lots of documentation files
   beagle/      DOS-only tool for analysis of Tierra output.
   alcomm/      UNIX/X11 tool for observing Tierra while it is running.
   tierra/      Source code for Tierra itself.
References:
   Ray, T. S.  1991.  Is it alive, or is it GA?
   {\it In} : Belew, R. K., and L. B. Booker [eds.], Proceedings of the 1991
   International Conference on Genetic Algorithms, 527--534.  San Mateo, CA:
   Morgan Kaufmann.
   
   Ray, T. S.  1991.  An approach to the synthesis of life.
   {\it In} : Langton, C., C. Taylor, J. D. Farmer, \& S. Rasmussen [eds],
   Artificial Life II, Santa Fe Institute Studies in the Sciences of
   Complexity, vol. XI, 371--408.  Redwood City, CA: Addison-Wesley.
   
   Ray, T. S.  1991.  Population dynamics of digital organisms.
   {\it In} : Langton, C. G. [ed.], Artificial Life II Video Proceedings.
   Redwood City, CA: Addison Wesley.
   
   Ray, T. S.  1991.  Evolution and optimization of digital
   organisms.  {\it In} : Billingsley K. R., E. Derohanes, H. Brown, III
   [eds.], Scientific Excellence in Supercomputing: The IBM 1990
   Contest Prize Papers, Athens, GA, 30602: The Baldwin Press, The
   University of Georgia.  Publication date: December 1991.
   
   Ray, T. S.  1992.  Evolution, ecology and optimization of
   digital organisms.  Santa Fe Institute working paper 92-08-042.
   
   Ray, T. S.  1992.  J'ai jou\'{e} \`{a} Dieu et cr\'{e}\'{e}
   la vie dans mon ordinateur.  Le Temps strat\'{e}gique 47: 68--81.
   
   Ray, T. S.  In press.  Evolution and complexity.  {\it In}:
   Cowan, George A., David Pines and David Metzger [eds.],
   Complexity: Metaphor and Reality.  Addison-Wesley Publishing Co.
   
   Ray, T. S.  In press.  An evolutionary approach to synthetic biology,
   Zen and the art of creating life.  Artificial Life 1(1): xx--xx.
   
   Ray, T. S.  In press.  Jugu\'{e} a ser Dios y cre\'{e} la
   vida en mi computadora.  {\it In}: Claudio Guti\'{e}rrez [ed],
   Epistemolog\'{i}a e Inform\'{a}tica.  San Jos\'{e}, Costa Rica:
   UNED, 1993.
   
   Ray, T. S.  In press.  Title unknown.  Virtual (Italian magazine),
   December 1993.
   
   Ray, T. S.  Submitted.  Evolution, complexity, entropy,
   and artificial reality.  Physica D.
   
   Ray, T. S.  Submitted.  How I created life in a virtual universe.
   Natural History Magazine, American Museum of Natural History.
Last Web update on Mon Feb 13 10:20:06 1995 
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