The current usage of the term artificial life (ALife) began in the late 1980s when the field was established by American computer scientist Chris Langton. The term was used in 1987 as a title for the “interdisciplinary workshop on the synthesis and simulation of living systems” organized in Los Alamos, New Mexico. There is a biannual international conference series called Artificial Life XI that alternates with the biannual European Conference on Artificial Life (ECAL). Langton was the first Editor-in-Chief of the journal, Artificial Life, founded in 1993 and the journal is coordinated through the International Society for Artificial Life (ISAL), which was established in 2001.
Alife was originally defined by Langton as “life made by man rather than by nature”, meaning it is the study of man-made systems that show behaviors characteristic of natural living systems. Langton changed the definition in 1998 to “the study of natural life, where nature is understood to include rather than to exclude, human beings and their artifacts”. Alife is interdisciplinary and includes the study of life and life-like processes and attempts to understand living systems by artificially synthesizing simple life-like systems. There are three intertwining branches of artificial life using computers, machines or molecules. “Soft” artificial life works in simulations or other purely digital constructions that exhibit life-like behavior, such as Lenia. “Hard” artificial life builds hardware implementations of life-like systems such as swarm robotics. “Wet” artificial life synthesizes living systems from biochemical substances.
The themes of Alife include origins of life, autonomy, self-organization, adaptation (evolution, development and learning), ecology, artificial societies, behavior, computational biology, artificial chemistries, information, living technology, art and philosophy.
In the theme of autonomy, the term “autopoiesis” was coined by Maturana and Varela (1980) to characterize a network of processes that self-maintains its organization. Autopoiesis is now understood to include both self-organizing and self-producing aspects. A computer model created by these biologists in 1974 may be considered as one of the first examples of Alife. The idea of autopoiesis is sometimes formalized as operational closure, which can be considered a network of processes where each process enables and is enabled by at least one other process in the network. Using this concept, Varela has described other biological systems such as the nervous system and the immune system as autonomous, even though they do not chemically self-reproduce.
In robotics autonomy not does not include self-production, but instead refers to the capacity of a system to move and interact without depending on remote control by an operator. Rather than micromanaging many aspects of a system’s behavior, behavior-based robots have been developed.
Models of collective behavior such as flocks, schools, herds, crowds and swarming fall under self-organization. Self-replication can be seen as a special case of self-organization. Homeostasis is related to self-maintenance which can be viewed as a special case of self-organization and has been studies in relation to artificial chemistries. In hard Alife, self-assembling or self-reconfiguring robots have been researched. Insect swarming has been used as inspiration for robots.
Since chemical components are non-living, but form living systems, artificial chemistries are used to study questions related to origin of life from chemical components. One example is the computer simulation introduced by Varella, Maturana and Uribe in 1974, of the formation of a protocell with a metabolic network and a boundary, which introduced the concept of autopoiesis. Other examples include M,R systems, chemoton, hypercycle, autocatalysis and algorithmic chemistry. Artificial chemistries also include evolution.
The field of synthetic biology has historical connections to artificial life research. Both synthetic biology and artificial life strive to design “life as it could be”, living systems designed for a specific purpose, or for scientific inquiry and both use systems biology thinking and synthetic methodology. Synthetic biology may be considered a form of wet artificial life. The 'holy grail' of wet artificial life and synthetic biology has been stated to be creation of an artificial cell or synthetic cell, out of biochemicals or biological parts.
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- Theoretical biologyA branch of biology that uses mathematical and computational tools to model and represent biological processes
- Synthetic biologyInterdisciplinary branch of biology and engineering, applying multiple disciplines to build artificial biological systems for research, engineering, and medical applications.