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Tierra: Evolution of digital organisms

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.]
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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: 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 Author(s): Tom Ray or [Tom's Current email is; mail to 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.
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