Page 21 - Biomimetics : Biologically Inspired Technologies

Bar-Cohen : Biomimetics: Biologically Inspired Technologies DK3163_c001 Final Proof page 7 21.9.2005 6:40pm

Introduction to Biomimetics 7

much broader than recombining DNA. The possibility of synthetically producing living cells
fromscratch is increasingly becoming a near future potential (http://www.nature.com/cgi-taf/
DynaPage.taf?file ¼ /nature/journal/v431/n7009/full/431624a_fs.html). This subject, however,
will not be covered any further in this book since the subject is outside the scope of the book’s
objective.

1.3 ARTIFICIAL LIFE

The name artificial life (A-Life) suggests the synthesizing of life from nonliving components.
A-Life is a technical field that is dedicated to the investigation of scientific, engineering, philo-
sophical, and social issues involved in our rapidly increasing technological capability to synthesize
from scratch life-like behaviors using computers, machines, molecules, and other alternative media
(Langton, 1995). A-Life focuses on the broad characteristics of biology and contributes to the
development of machines that evolve, sociable robots, artificial immune systems that protect
computers from malicious viruses, and virtual creatures that learn, breed, age, and die. Moreover,
biologists can now study evolution in virtual worlds, and medical students and doctors can study
operation mechanisms of various living organs, including the heart with its cells, enabling learning
in ways that are impossible with actual living organs.
The field of A-Life consists of a broad range of topics related to the synthesis and simulation of
living systems in the form of self-replicating computer code that allows learning about fundamental
aspects of evolution and their ecological context (Ray, 1992). The enormous advances of computer
capability have led to the creation of an incredible computation and information processing power in
support of the analytical development of biologically inspired capabilities. These advances have led
to biological concepts and systems that are systematically modeled, copied, or adapted (Chapters 4
and 5; Adami, 1998) enabling predictions of what life can be beyond what we know from empirical
research. Some of the topics that are covered under the umbrella of A-Life include origin of life,
evolutionary and ecological dynamics, self-assembly, hierarchy of biological organization, growth
and development, animal and robot behavior, social organization, and cultural evolution.
A-Life is often described as the effort to understand high-level behavior using low-level rules
that are based on the laws of physics. The field itself covers the simulation or emulation of living
systems or parts of living systems with the intent to understand their behavior. Another aspect of
this field is the attempt to study emergent properties of living populations, usually by making a
simulation of many agents and neglecting the precise details of members of an individual popula-
tion. Adami (1998) approached the field of A-Life from physical sciences with life-like entities
taking life as a property of an ensemble of units that share information coded in a physical substrate.
In the presence of noise, each unit manages to keep its entropy significantly lower than the maximal
entropy of the ensemble. This information is shared on timescales that exceed the ‘‘natural’’
timescale of decay of the information-bearing substrate by many orders of magnitude. For this
purpose, he introduced the necessity for a synthetic approach and formulated a principle of living
systems based on information and thermodynamic theory.
The founding of the field of A-Life is attributed to John Horton Conway, a mathematician from
the University of Cambridge, who in 1968 invented a game called ‘‘The Game of Life’’ (Gardner,
1970). Using a simple system inspired by cell biology, this game exhibits complex, life-like
behavior. The rules involve cell patterns that move across the Life universe, simulating life in the
form of living and dead objects. After playing the game for a while, Conway discovered an
interesting emergence of a pattern of five cells. He named this stable, repeating cell pattern, glider.
This discovery was followed by R. William Gosper, Jr, who designed a glider gun that fires new
gliders every 30 turns. The glider gun proved that it was possible for a single group of living cells to
expand into the Life universe without limit (Levy, 1984; and Gardner, 1983). Later, using powerful
computers, the study expanded into ‘‘organisms’’ in the Life universe with some starting at random