4.5 Darwin Evolved and Devolved
57
tions, there were major evolutionary transitions (Maynard Smith and Szathm´ ary,
1997): the emergence of eukaryotic cells, multicellular organisms, and, on a still
higher level, consciousness and language. There were catastrophes causing mass
extinctions that prompted movement into vacated ecological niches. It is certain
that the pace of biological evolution was highly variable for different species and
in different epochs but, save catastrophes, the geological record provides a clock
scaled in millennia, and even on this scale it is uncertain due to scarcity of data.
Even a faster human-driven evolution does not happen before our eyes; it took quite
a while to turn a wolf into a chihuahua. Darwin himself just took the trouble to
confront the creation myths and support Charles Lyell’s views of gradual geological changes juxtaposed with the catastrophism of Georges Cuvier, while he himself
recorded the fast divergence of his famous finches on the geologically young Galapagos Islands. The popularity of the theory of punctuated equilibria was attributed
by critics to Gould’s rhetorical skills and brilliant prose rather than to its unique
message.
Eigen (1971) viewed the trajectory of the inevitable evolutionary process as an
arrow defining the privileged direction of time, which applies to all living systems
and is even more pronounced and meaningful than the unidirectional increase of entropy in any irreversible process. In his words, the terms “good” and “evil” assume
a meaning as soon as single information carriers start to interact and thereby mutually increase or diminish their values. The inevitability of evolution leading to an
increase of a “value function”, or fitness, in whatever way it be defined, prompted
creation of the various evolutionary algorithms (see, e.g., Ashlock, 2006). A population of programs subject to mutations is selected by their ability to solve a computational problem, with weaker (“less fit”) performers eliminated on the way.
An advantage of computers over the real world is that everything goes fast. However, evolutional optimization has also been implemented in vivo in the experiment
by Richard Lenski, started in 1988 and, not being as fast as in silico, continuing
for many years and many thousands generations of the bacteria E. coli. It demonstrated the adaptation of bacteria, increasing their fitness (measured by efficiency in
consuming nutrients) in different sugary solutions and at different temperatures, as
well as evolving resistance to virulent phage. After more than thirty thousand generations, bacteria even managed to spontaneously acquire the ability to metabolize
another organic component of the solution, citrate, which earlier generations could
not utilize (Barrick et al, 2009). Neither in vivo nor in silico did an intelligent creator
interfere, and it should have been sufficient to bury the watchmaker analogy forever.
Fast or slow, evolution never stops.The traditional assumption, going back to
Aristotle’s Scala Naturae (Lovejoy, 1965), is that it brings about a steady rise
to higher complexity, in about the same order as in the Great Chain of Being
(Fig. 4.10). Of course, the old drawing on the left does not imply that angelic beings in the upper row had evolved from humans (though why not? – aren’t good
Christians keen to rise to a heavenly paradise?), but the biblical Creation had indeed
followed the path from plants to animals to man, as depicted here. A much later
picture from Scientific American in the right panel depicts the same sequence, just
putting man at the bottom, perhaps as a hint.
57
tions, there were major evolutionary transitions (Maynard Smith and Szathm´ ary,
1997): the emergence of eukaryotic cells, multicellular organisms, and, on a still
higher level, consciousness and language. There were catastrophes causing mass
extinctions that prompted movement into vacated ecological niches. It is certain
that the pace of biological evolution was highly variable for different species and
in different epochs but, save catastrophes, the geological record provides a clock
scaled in millennia, and even on this scale it is uncertain due to scarcity of data.
Even a faster human-driven evolution does not happen before our eyes; it took quite
a while to turn a wolf into a chihuahua. Darwin himself just took the trouble to
confront the creation myths and support Charles Lyell’s views of gradual geological changes juxtaposed with the catastrophism of Georges Cuvier, while he himself
recorded the fast divergence of his famous finches on the geologically young Galapagos Islands. The popularity of the theory of punctuated equilibria was attributed
by critics to Gould’s rhetorical skills and brilliant prose rather than to its unique
message.
Eigen (1971) viewed the trajectory of the inevitable evolutionary process as an
arrow defining the privileged direction of time, which applies to all living systems
and is even more pronounced and meaningful than the unidirectional increase of entropy in any irreversible process. In his words, the terms “good” and “evil” assume
a meaning as soon as single information carriers start to interact and thereby mutually increase or diminish their values. The inevitability of evolution leading to an
increase of a “value function”, or fitness, in whatever way it be defined, prompted
creation of the various evolutionary algorithms (see, e.g., Ashlock, 2006). A population of programs subject to mutations is selected by their ability to solve a computational problem, with weaker (“less fit”) performers eliminated on the way.
An advantage of computers over the real world is that everything goes fast. However, evolutional optimization has also been implemented in vivo in the experiment
by Richard Lenski, started in 1988 and, not being as fast as in silico, continuing
for many years and many thousands generations of the bacteria E. coli. It demonstrated the adaptation of bacteria, increasing their fitness (measured by efficiency in
consuming nutrients) in different sugary solutions and at different temperatures, as
well as evolving resistance to virulent phage. After more than thirty thousand generations, bacteria even managed to spontaneously acquire the ability to metabolize
another organic component of the solution, citrate, which earlier generations could
not utilize (Barrick et al, 2009). Neither in vivo nor in silico did an intelligent creator
interfere, and it should have been sufficient to bury the watchmaker analogy forever.
Fast or slow, evolution never stops.The traditional assumption, going back to
Aristotle’s Scala Naturae (Lovejoy, 1965), is that it brings about a steady rise
to higher complexity, in about the same order as in the Great Chain of Being
(Fig. 4.10). Of course, the old drawing on the left does not imply that angelic beings in the upper row had evolved from humans (though why not? – aren’t good
Christians keen to rise to a heavenly paradise?), but the biblical Creation had indeed
followed the path from plants to animals to man, as depicted here. A much later
picture from Scientific American in the right panel depicts the same sequence, just
putting man at the bottom, perhaps as a hint.