Avida is an artificial life software platform to study the evolutionary biology of

self-replicating Self-replication is any behavior of a dynamical system that yields construction of an identical or similar copy of itself. Biological cells, given suitable environments, reproduce by cell division. During cell division, DNA is replicated and ca ...

and evolving computer programs ( digital organisms). Avida is under active development by Charles Ofria's Digital Evolution Lab at

Michigan State University Michigan State University (Michigan State, MSU) is a public university, public Land-grant university, land-grant research university in East Lansing, Michigan. It was founded in 1855 as the Agricultural College of the State of Michigan, the fi ...

; the first version of Avida was designed in 1993 by Ofria, Chris Adami and C. Titus Brown at Caltech, and has been fully reengineered by Ofria on multiple occasions since then. The software was originally inspired by the Tierra system.

Design principles

Tierra simulated an evolutionary system by introducing computer programs that competed for computer resources, specifically processor (CPU) time and access to main memory. In this respect it was similar to

Core Wars ''Core War'' is a 1984 programming game created by D. G. Jones and A. K. Dewdney in which two or more battle programs (called "warriors") compete for control of a virtual computer. These battle programs are written in an abstract assembly lang ...

, but differed in that the programs being run in the simulation were able to modify themselves, and thereby evolve. Tierra's programs were artificial life organisms. Unlike Tierra, Avida assigns every digital organism its own protected region of memory, and executes it with a separate virtual

CPU A central processing unit (CPU), also called a central processor, main processor or just processor, is the electronic circuitry that executes instructions comprising a computer program. The CPU performs basic arithmetic, logic, controlling, and ...

. By default, other digital organisms cannot access this memory space, neither for reading nor for writing, and cannot execute code that is not in their own memory space. A second major difference is that the virtual CPUs of different organisms can run at different speeds, such that one organism executes, for example, twice as many instructions in the same time interval as another organism. The speed at which a virtual CPU runs is determined by a number of factors, but most importantly, by the ''tasks'' that the organism performs: logical computations that the organisms can carry out to reap extra CPU speed as bonus.

Use in research

Adami and Ofria, in collaboration with others, have used Avida to conduct research in digital evolution, and the scientific journals '' Nature'' and '' Science'' have published four of their papers. The 2003 paper "The Evolutionary Origin of Complex Features" describes the evolution of a mathematical

equal Equal(s) may refer to: Mathematics * Equality (mathematics). * Equals sign (=), a mathematical symbol used to indicate equality. Arts and entertainment * ''Equals'' (film), a 2015 American science fiction film * ''Equals'' (game), a board game ...

s operation from simpler bitwise operations.

Use in education

The Avida-ED project
Avida-ED
uses the Avida software platform within a simplified graphical user interface suitable for use in evolution education instruction at the high school and undergraduate college level, and provides freely available software, documentation, tutorials
lesson plans
and other course materials. The Avida-ED software runs as a web application in the browser, with the user interface implemented in JavaScript and Avida compiled to JavaScript using Emscripten, making the software broadly compatible with devices commonly used in classrooms. This approach has been shown to be effective in improving students' understanding of evolution. The Avida-ED project was the winner of the 2017 International Society for Artificial Life Education and Outreach Award.

References

"Testing Darwin"
Discover Magazine, February 2005.

External links

Avida Software - GitHubAvida-ED Project - Robert T. PennockAn Avida Developer's SiteMSU Devolab website

Scientific publications featuring Avida

* C. Adami and C.T. Brown (1994), Evolutionary Learning in the 2D Artificial Life Systems Avida, in: R. Brooks, P. Maes (Eds.), Proc. Artificial Life IV, MIT Press, Cambridge, MA, p. 377-381. *

R. E. Lenski Richard Eimer Lenski (born August 13, 1956) is an American evolutionary biologist, a Hannah Distinguished Professor of Microbial Ecology at Michigan State University. He is a member of the National Academy of Sciences and a MacArthur fellow. ...

, C. Ofria, T. C. Collier, C. Adami (1999). Genome Complexity, Robustness, and Genetic Interactions in Digital Organisms. ''Nature'' 400:661-664. * C.O. Wilke, J.L. Wang, C. Ofria, R.E. Lenski, and C. Adami (2001). Evolution of Digital Organisms at High Mutation Rate Leads To Survival of the Flattest. ''Nature'' 412:331-333. * R.E. Lenski, C. Ofria, R.T. Pennock, and C. Adami (2003). The Evolutionary Origin of Complex Features. ''Nature'' 423:139-145. * S.S. Chow, C.O. Wilke, C. Ofria, R.E. Lenski, and C. Adami (2004). Adaptive Radiation from Resource Competition in Digital Organisms. ''Science'' 305:84-86. * J. Clune, D. Misevic, C. Ofria, R.E. Lenski, S.F. Elena, and R. Sanjuán. Natural selection fails to optimize mutation rates for long-term adaptation on rugged fitness landscapes. PLoS Computational Biology 4(9): 2008. {{doi, 10.1371/journal.pcbi.1000187 * Clune J, Goldsby HJ, Ofria C, and Pennock RT (2011) Selective pressures for accurate altruism targeting: Evidence from digital evolution for difficult-to-test aspects of inclusive fitness theory. Proceedings of the Royal Society
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* Benjamin E. Beckmann, Philip K. McKinley, Charles Ofria (2007). Evolution of an adaptive sleep response in digital organisms. ''ECAL 2007'
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Artificial life Artificial life models Digital organisms