References

3 Charles Darwin and the ‘Root Brain’ 45
Table 3.1. Characteristics of subsystems s11–s20 which process information. (After Miller
and Miller 1995)
s11. Input transducer. A sensory subsystem which brings markers bearing information into
the system, changing them into a form suitable for further transmission within the system
s12. Internal transducer. The sensory subsystem which receives markers bearing information
about significant alterations in subsystems or components, and which converts them
into a form suitable for transmission
s13. Channel and net. A subsystem composed of a route or a set of interconnected routes
over which markers bearing information are transmitted throughout the system
s14. Timer. A subsystem which transmits to the decider (s18) information about timerelated
states of the environment or components of the system. This information signals
to the decider that certain processes should stop, start, or alter in rate, or advance or delay
their phase
s15. Decoder. The subsystem which alters information received from s11 and s12 into
a private code used internally by the system
s16. Associater. A subsystem which forms enduring associations among items of information
andthusenablesthefirststageoflearning
s17. Memory. A subsystem that carries out the second stage of the learning process, storing
information for different periods of time and then retrieving it
s18. Decider. An executive subsystem which receives information inputs from all other
subsystems and transmits to them information outputs
s19. Encoder. The counterpart of s15 whereby information is converted from a private code
used internally by the system to one which can be interpreted by other nearby systems
s20. Output transducer. The subsystem concerned with the output of informational markers
into the channels in the systems environment
three main groups concerned with the processing of (1) matter–energy
and information, (2) matter–energy alone, and (3) information only. The
organism and its supraorganismic environment are also deconstructed
into a hierarchy, the first four levels of which are (1) cell, (2) organ, (3)
organism, and (4) group. Each level of organisation owes its existence
and identity to the same set of 20 subsystems. These subsystems, and the
processes which they contain, support and define each level of organisation.Itisthislastpointwhichaccountsforthefactthatthelevelsof
organisation show self-similarity. That is, each level is supported by a similar
set of subsystems, though, obviously, the items which correspond to
each subsystem materially differ at each level. The processes or properties
that characterise the third main group of information-processing subsystems
are listed in Table 3.1. They are the ones relevant to the plant-brain
problem.
Inanearlieressayontherelationbetweenlivingsystemstheoryandplant
life (Barlow 1999), it was clear that there were gaps and uncertainties in the