Abstract
Evolution is a mode of natural
dynamics par excellence, in which many participants interact with
each other. In particular, any dynamics can identify itself by
explicating how it addresses itself to the following two questions.
(1) How does each participant come to detect others? (2) How does
each move with and act upon others? The Galilean-Newtonian mechanics
concentrates on the second question on movement dynamics by dismissing
the significance of the first question on detection dynamics only
except for mentioning its role of identifying the initial conditions.
Thermodynamics, on the other hand, emphasizes the role of detection
dynamics as demonstrated in its second law stating that if the
process of detection proceeds only locally as it should, movement
dynamics would necessarily exhibit an irreversible enhancement
of randomization. We note that any detection dynamics proceeding
internally is local in the sense that complete identification
of evolving systems in a globally simultaneous manner is not attainable.
Detection dynamics of necessarily local character comes to imply
that there is an inevitable time-delay between detecting others
in the neighborhood and acting upon them accordingly. The time-delay
between detection and action perceived by each participant, or
in the eyes of the participants, serves as a causative factor
of evolutionary dynamics of any type. Most indicative of the time-delay
between detection and action is heterotrophic activity, in the
latter of which an arbitrary participant in an evolutionary process
has the capacity of taking in necessary material resources as
responding to detecting what its neighborhood looks like. Although
it leaves behind only material flow continuity, heterotrophic
activity as the capacity of wanting material resources for the
sake of the continuity in the record is an agency connecting between
detection and movement dynamics.
1 Introduction
Among many alternatives, there is one unique perspective toward evolutionary processes, namely, the perspective of the participants in evolution (Matsuno, 1989; Salthe & Matsuno, 1993). One can, however, immediately find that this insider's view of evolution is very subtle. No matter how strongly one may wish to advocate the insider's view, this position is still the outsider's enabling the viewer to see how the insiders would behave. This problem is of course not new. What we would like to push forward is to ask ourselves whether there is any possibility to save the insider's or internalist viewpoint in evolution and if so, to see the extent to which it may be possible.
To begin with, let us start from a very quick survey of the viewpoint available to how dynamics is formulated and perceived. Needless to say, evolution is a mode of natural dynamics par excellence. As a matter of fact, any dynamics has two components. One is the process of detection, and the other is that of movement.
In mechanics in physics, a very strange stipulation has been accepted and taken for granted. That is, any detection could supposedly be accomplished instantaneously over the whole space (Earman, 1986). Such an instantaneous accomplishment of detection over the whole space guarantees legitimacy and identification of initial-boundary conditions. Once initial-boundary conditions are identified, all the rest is the movement of things that can uniquely be determinate through the law of motion.
What is unique to mechanics, whether classical or quantum, is a complete detection accomplished instantaneously and the movement of things that cannot remain indecisive. Mechanics thus does not necessitate the internalist perspective that could differ from the externalist one. As far as the externalist perspective like that of physicists is guaranteed, there would be no need to invoke the internalist position or the perspective of the participants. But, the price to be paid for the dismissal of the internalist perspective is to admit an unphysical detection process propagating at an infinite velocity. In other words, mechanics did not assume that the observer was a physical being. Simultaneous and instantaneous detection in mechanics is to assume the presence of nonphysical intelligent beings capable of communicating at an infinite velocity (Rychlak, 1991). The only difference between classical and quantum mechanics is that in quantum mechanics, we do not let such an instantaneous detection inevitable to its theoretical framework be also inevitable to physical detections proceeding in reality. The problem of actual detection and measurement in quantum mechanics is taken to be the problem to be examined in its own light (Matsuno, 1985).
Once it is admitted that any detection is communicated at a finite velocity internally, every material participant in the process, whether it may be a molecule or a human being (Artigiani, 1993; Csanyi, 1993), can only be in one place at a time and not everywhere at once. This lack of simultaneous communication necessarily leads to an internal conflict such that how to detect others depends upon which path the communication would take and the detections of the same object through different communication paths would give different results. This kind of conflicts in detection would never happen in mechanics because there, no time-delay is allowed irrespective of whatever communication path may be taken.
Detection internal to natural dynamics is inevitably incomplete and conflicting internally (Matsuno, 1989). However, the movement of things has to be definite and determinate as in the case of mechanics, because things, whether they may be matter or field, cannot remain indecisive. Any movement has to be complete and consistent globally. In fact, there is a finite time-delay between detection and movement or action. What now turns out to be evident at this point from the trios of internally conflicting detections, globally consistent movement and the time-delay between detection and action is that movement or action is solely responsible for eliminating those internal conflicts arising from internal detections as leaving behind no conflicts in the record. It is not an impartial uncommitted externalist, but the mutually conflicting, committed participants that make the world go round.
Unique to natural dynamics is internal movement toward a global consistency from those local detections conflicting internally. What is more, this movement cannot be stopped once gets started. For any movement anywhere is to be detected elsewhere later at a time and causes internal conflicts in detection subsequently. In short, change a little something somewhere and everything else changes subsequently. Constant generation of changes is latent in natural dynamics as a transformation from internally conflicting detections to a globally consistent movement (Matsuno, 1992a). This property of constant generation of changes exhibits a marked contrast to mechanics, in the latter of which dynamics proceeds from a globally consistent and complete detection to the similarly consistent and complete movement. There is no need for eliminating internal conflicts because there is none. There are neither changes nor chances in mechanics. One has to supply changes externally insofar as one stays in the framework of mechanics.
In contrast, natural dynamics
as a transformation from an internally conflicting, incomplete
detection to globally consistent movement serves as a generator
of changes. But, this generator is not the prey of pure chance
(Laszlo, 1993). Insofar as one notes that fulfilling various conservation
laws such as on energy and on matter are referred to as a necessary
condition for any movement, the internal movement toward a global
consistency is seen in the process of generating only those changes
that could fulfill these conservation laws in the actual movement.
At this point, one should emphasize that incomplete detection
cannot completely control the movement, as differing from the
case of mechanics in which movement is completely controlled by
what is detected. Internal movement for completion in natural
dynamics maintains in itself the capacity of actualizing movements
in the manner not fully controlled by detection.
2 Heterotrophic Activity in Natural Dynamics
When energy flow continuity as a local expression of the conservation of energy that is empirically incontrovertible is taken as an attribute of movement, then the internal movement toward a global consistency actualizes itself as that toward fulfilling energy flow continuity (Matsuno, 1989). Here, one can see an instance of those movements due to that, for the sake of which they are making the case. Internal movement for fulfilling energy flow continuity is just another name of heterotrophic activity that is so ubiquitous in biology (Matsuno, 1992b). The origin of heterotrophic activity is very simple and physical. It arises from the internal movement for energy flow continuity conditioned by the presence of the inevitable time-delay between detection and action. Needless to say, heterotrophic activity comes from an internalist perspective, because appraisal of internally conflicting detections that underlie heterotrophic activity is characteristic exclusively to internalists or the participants in the game. To externalists, on the other hand, heterotrophic activity means simply that there is no such things as a free-lunch in the real world and that one party's gain is just another party's loss and nothing more. Externalists cannot see those conflicts internalists are seriously facing. What externalists can see instead is the completed movement that has already been finished in a globally consistent manner.
Heterotrophic activity is in fact a way of playing with probabilities as preventing each participant from becoming a mere miserable victim of chance while observing the materially incontrovertible constraint identified as energy flow continuity as an invincible form of grammar. As a matter of fact, heterotrophic activity is a form of stochastic laws allowing alternatives and at the same time tailoring chances in the manner suited exclusively to internalists (Laszlo, 1993).
One can now associate heterotrophic activity with consumer-regulated dynamic as a polar opposite to supplier-controlled one, because heterotrophic activity materializes in consumers. While suppliers behave as externalists toward those that consume what are supplied, consumers behave as internalists in the respect that they found their behaviors upon heterotrophic activity internal to themselves. Consumer-regulated dynamics puts its primary focus upon consumers as letting suppliers meet what consumers require, being contrary to the case of supplier-controlled dynamics letting consumers cope with what suppliers have already provided.
Consumer-regulated dynamics based upon heterotrophic activity requires at least three hierarchical levels (Salthe, 1985,1989); the focal, upper and lower levels. It is the focal level which supplies the products to meet the consumption at the upper by recruiting necessary resources from the lower level. In contrast, only two levels, the focal and the lower, are required as a minimum condition for supplier-controlled dynamics in which the focal level is involved in production process as utilizing resources from the lower level irrespective of whether or not the upper level behaving as a consumer is present.
Evolutionary significance of consumer-regulated
dynamics is in its sustainability compared to supplier-controlled
counterpart. In view of the fact that evolutionary sustenance
of any consumer is in the availability of resources to be consumed,
supplier-controlled dynamics would easily lead to an extinction
of the lower level to be exploited by the focal level as increasing
the extent of production there. By contrast, consumer-regulated
dynamics is less prone to its failure due to resource depletion,
because the extinction of the lower level to be exploited by the
focal level could be possible only when the consumption to be
met would be available from the upper. The runaway explosion of
production at the focal level within the scheme of supplier-controlled
dynamics could happen through production process solely at that
level, whereas such an explosion for consumer-regulated dynamics
could be possible only when there could be maintained a coordination
among three of the focal, upper and lower levels leading to a
runaway explosion. Evolutionary sustenance of dynamics favors,
by definition, the one that could postpone indefinitely its own
bankruptcies such as a runaway explosion of production. As a matter
of fact, consumer-regulated dynamics fills the role of evolutionarily
sustainable dynamics.
3 Occasional Extinctions of Species
Runaway explosions of supply and consumption in natural evolutionary dynamics can lead to extinctions of species if any one of trophic levels in evolving ecosystems has exhaustively been exploited. If the lowest trophic level would be exhausted, most of the then existing species would go extinct. In particular, the Permian-Triassic boundary occurred at almost 225 million years ago was marked by high extinction rates of Palaeozoic phytoplankton accompanied by those documented for skeletonized marine invertebrates (Sepkoski, 1983; Knoll, 1989). Similarly, the Mesozoic-Cainozoic phytoplankton record including the Cretaceous-Tertiary boundary at about 65 million years ago clearly parallels palaeozoological data on the timing and severity of mass extinctions (Haq, 1973; Bujak & Williams, 1979; Roth, 1987; Knoll, 1989). Nevertheless, closer examination of those records reveals a more complex picture. Several marine invertebrate groups as well as the calcareous nannoplankton declined in diversity through part or all of the Maastrichtian, but extinctions do not cluster at the K-T boundary (Roth, 1987). Phytoplanktonic extinctions from late Eocene to early Oligocene took place throughout an interval of several million years, but do not show uniquely high or even notable increases in extinction rate at the E-O boundary (Corliss et al, 1984). On the other hand, the K-T boundary is characterized by truly high rates of extinction during a very short interval followed by expansion of disaster species which, proliferating after major extinctions, look tolerably like those that disappeared (Perch-Nielsen, 1985). The E-O boundary, on the other hand, is characterized by moderate rates of extinction spread through several million years followed by unusually low rates of origination, while the Miocene phytoplankton diversification in the Cainozoic era cannot be related to the clearing of ecosystems by mass extinction (Knoll, 1989).
Recorded parallel extinctions
between phytoplankton and palaeozoological species suggest that
both suppliers and consumers of trophic energy went extinct roughly
at the same time. However, the extinction of consumer follows
that of supplier, but not vice versa. Analyzing this sequence
of extinction can provide further classification of the paths
toward extinction depending upon how the runaway explosion of
supply and consumption develops in time, as demonstrated in the
difference between the K-T and the E-O boundary episodes.
4 Consumer Power
Although it would be inevitable to have a runaway explosion of supply and consumption in the long run if supplier-controlled trophic dynamics in one form or another is allowed to intervene, there could also be a room of resource-guaranteed trophic dynamics over only a limited time interval in an approximate sense. Resources to consumer would temporarily be guaranteed if there is a finite time interval over which resources for consumer may be available without being depleted independently of how they would be consumed. This type of interplay between supplier-controlled and consumer-regulated trophic dynamics turns out to be substituted by a form of consumer-regulated dynamics under temporary resource guarantee. Consequently, maximization of the efficiency in resource utilization reduces to a common denominator of consumer-regulated trophic dynamics under temporary resource-guarantee as evidenced in the ecological succession toward its climax (Margalef, 1968; Matsuno, 1978). However, maximization of the efficiency of resource utilization cannot continue indefinitely because resources available to consumption eventually comes to depend upon how they have been consumed or usurped including the possibility of being completely exhausted.
Prevalence of consumer-regulated trophic dynamics is rooted in eventual sustenance of ecosystems (Brown & Vincent, 1992) even if depletion of some of the trophic levels is inevitable due to the runaway explosion of supply and consumption. Genesis of new consumers as evidenced in the appearance of disaster species in the vacuum made by mass extinctions near at the K-T boundary can be a typical example of the functioning of consumer-regulated dynamics (Knoll, 1989).
Less drastic manifestation of consumer-regulated trophic dynamics is alternation of species on the same trophic level. Major predators of epifaunal suspension-feeding ophiuroids or brittlestar beds in the Mesozoic were teleostean fishes, neoselachian sharks and decapod crustaceans, while seastars, fishes and crabs are their predators in modern ecosystems (Aronson, 1992). A more pronounced case is alternation of dinosaurs by mammals near at the K-T boundary.
Specialization of resources to
be consumed comes to localize the scope and the extent of would-be
extinctions. In fact, the lush subtropical dinosaurs' habitats
were gradually giving way to cooler temperate forests which favored
mammals in the last several hundred thousand years of the Cretaceous
(Benton, 1990). Whether one may take as a model of the mass extinction
near at the K-T boundary either the gladualist ecological succession
model of Van Valen (1984) or the catastrophist extraterrestrial
impact one of Alvarez (1983, 1987), the extinction of the dinosaurs
was observed to occur over the period of 7 million years, with
an acceleration of the rate in the last 0.3 million years (Sloan
et al, 1986). These palaeontological records confirm terminal
Cretaceous extinctions on two time scales such as a slow decline
unrelated to the bolide impact and a sharp truncation being synchronous
with and probably caused by the impact (Alverez et al, 1984; Buffetaut,
1984; Kauffman, 1984). The alternation of dinosaurs by mammals
is thus seen as a consequence of the interplay between two dynamics,
one is endogenous and the other exogenous. What is endogenous
is the mutual interference between supplier-controlled and consumer-regulated
trophic dynamics among the then available suppliers and consumers.
Once a particular resource to a particular consumer is depleted
due to the runaway explosion of both supply and consumption, the
extinction of the consumers involved would become inevitable and
only those consumers that did not rely upon the depleted resources
could come to dominate the surviving ecosystems.
5 Concluding Remarks
Natural dynamics implements itself in the transition from internally conflicting detections to a globally consistent movement. Consumer-regulated dynamics grounded upon heterotrophic activity is just a representative case of such natural dynamics. In fact, evolution exhibits an autonomy of consumer-regulated dynamics by letting every participant be an agent consuming others, though occasionally interrupted by inevitable supplier-controlled dynamics. Intrusion of supplier-controlled dynamics may lead to occasional bursts, extinctions or bankruptcies of species in evolution while accompanied by temporary enhancement of the efficiency of resource utilization.
One lesson we may expect to get from the ubiquity of heterotrophic activity and consumer-regulated dynamics is that even though our linguistic instruments are extremely suitable for supplier-controlled dynamics or mechanics equipped with the capacity of complete global detection, natural dynamics is simply not the case. To ask to describe the inconsistency among internal detections in a consistent manner would come to violate the principle of the excluded middle or to destroy the underlying linguistic integrity.
A compromise is to allow within natural languages some room for violating the principle of the excluded middle and to pass the capacity of actualizing the global consistency onto the material participants like ourselves, instead of onto natural languages themselves that are uniquely human institutions.
Minimizing the supplier-controlled perspective with a mechanistic flavor and instead assimilating ourselves to the material participants in evolution provide a modest way to approach evolution and evolutionary thought.
References