Biology Reference
In-Depth Information
Table 5.11 Three mechanisms of interactions between systems and their environment predicted
by the generalized Franck-Condon principle (Sect.
2.2.3
).
R
S
rate of change of the system,
R
E
rate
of change of environment,
BDS
before-demand supply,
SDS
synchronous demand and supply,
ADS
after-demand supply
Rates
R
S
<<
R
E
R
S
¼
R
E
R
S
>>
R
E
Mechanisms
BDS
SDS
ADS
Examples
Enzymic catalysis
Predator-prey interactions
Biological evolution
response to environmental demand (in which case the environmental demand must
precede the internal state changes), (2) the system adjust its internal states simulta-
neously with the environmental demand, and (3) the system can readjust its internal
state in anticipation of environmental demand (in which case the internal state
changes must precede the environmental demand). We may refer to these
mechanisms as (1) the “after-demand supply” (ADS), (2) the “synchronous demand
and supply” (SDS), and (3) the “before-demand supply” (BDS), respectively. There
are two rate processes involved - the rate, R
S
, of internal state changes, and the rate,
R
E,
of the change in environmental demand. There are three possible scenarios
regarding the relative magnitudes of these rates as shown in Table
5.11
, which also
includes the suggested mechanisms for each scenario.
An example of SDS would be the uncertainty associated with a lion catching a
deer because their running speeds are comparable, that is, R
S
¼
R
E
: Sometimes the
lion succeeds in catching a deer and other times the deer gets away safely. An
example of BDS is provided by the phenomenon of conformational rearrangements
of enzymes (S) before they bind their substrates (E) since R
S
<<
R
E
, in agreement
with the generalized Franck-Condon principle and in contradiction to the induced
ADS would be the biological evolution where the life cycle of organisms (S) are
faster than the rate of change of their environment (E), that is, R
S
>>
R
E,
so that, in
order for organisms to evolve, the changes in their environment must first take place
before better fit organisms survive and less fit ones get removed in order for the
group (or lineage or taxon) to change its genome. Again this is the prediction