Evolutionary Signposts

EVOLUTIONARY SIGNPOSTS

By Roland Watson

I am now going to leave the admittedly difficult concepts of topology and chaos behind, and examine some other important aspects of evolution, the first of which is its subtlety. What I mean by this is that at any point in time, it is difficult, if not impossible, to see evolutionary changes in progress. Environmental disturbances, and species reactions and adaptations to them, do involve many incremental steps. Because of this, our tendency is to view all species, as they are right now, as fixed and permanent. However, this is incorrect. Some species are essentially fixed, and have been unchanged for millions of years, but the forms of others are much more recent, and some, perhaps many, are evolving right now.

It is a curious question, to look at other species of life, and wonder which are stationary, and which are effectively in-between forms, right now.

Most of the life forms that are evolving now are doing so to adapt to us, to the destructive changes that humans have made to their environments. Also, as such other life forms adapt to man, they are for the most part doing so behaviorally. They are not changing their genetically determined physical characteristics, because there is not enough time. Instead, they are attempting to modify their behavior, to find a survival strategy that works. Because of this, one can conclude that at the present time, most evolution, or attempts at it, are behaviorally-based.

The goal to save energy

Another extreme case of evolutionary subtlety reveals an additional underlying goal, which is to save energy. This is the degree of energy conservation that exists in the human brain, and which is achieved in a variety of ways. First, to quote Dr. Ratey's guide: "brain areas that are unused are seen as a waste of fuel." The consequence of this is that they are pruned. Secondly, brain areas that have been developed for one purpose are continually redirected to other ends. Different neurons participate in many different neural circuits, including types of circuits. Evolution of the brain has occurred, to quote Dr. Ratey again, "in the most economical way possible; the brain co-opts one structure that might have evolved for an entirely different purpose and applies it to another function altogether."

Examples such as these reflect a significant degree of, and need for, energy efficiency and conservation. Said another way, whatever specific functions evolutionary changes fulfill, they must also conform to this requirement: the need to minimize energy expenditure.

The last major aspect of evolution, and a reflection of this subtlety, is its time scale. Either over the course of a migration, or even in response to a major environmental shock, the process is usually, if not always, very lengthy. In addition, for the latter, because such shocks are unexpected, much life does not survive. It is unable to adapt and evolve. Therefore, many of the behaviorally-based evolutionary attempts that I just described, the desperate efforts of other life forms to adapt to us, will fail. Many, of course, already have failed. The species are now extinct.

How long does evolution take?

Evolution requires a great span of time, and this is a necessity. The ecology is extremely complex, and all attempts at evolution, all new characteristics that different species develop, must be tested within its structure. The only way to accomplish this is via a long process of trial and error. This is the only way to find what works: what enhances survival, and life - or the development of diversity, and what minimizes energy expenditure. This aspect of evolution, really, of life, is the most astonishing of all: that it works so hard, and for so long, to achieve its goals.

If you want a great expression of time, think of the number of years that it took for birds to evolve into hummingbirds and eagles and storks. Or, consider the time, the number of steps involved, for a fish to evolve into a human. I discussed steps in another series: the thousands of educational steps necessary to master a complex subject. Imagine what it takes to change, to alter radically, a physical form: millions, even billions, of physiological changes, and distinct expressions of will; all mixed together through an even greater number of chance circumstances; and all grouped together in distinct stages, separated by traumatic periods of chaos.

Humans today, and all other species, are the cumulative construction of all of this. Life is a work in progress, and it continues, through you and I. We are the present limit of evolution, leading the way to the future with our will, or being led by form, both genetic and behavioral. The latter is in a sense slavery, but the former is art, of the highest order: the art of creating life, not only of your own life, and the lives of your children, but also the lives of future species.

The evolutionary process is so astounding that it is hard to be believed. But, as yet, there are no reliable alternatives, and, in many cases, the pieces of the puzzle are being worked out.

The first life

There have been many evolutionary signposts, and the first of these is the initial formation - as opposed to creation - of life. And this, although there is intuition into the general process, and scientific evidence of some of the steps along the way, remains largely an unknown. The basic idea is that in the ecological conditions following the earth's formation, the different atomic elements came into contact with each other. And, as they did, this led to a variety of chemical reactions, and the formation of complex compounds and molecules. At some point, no one is certain of the date, but archaeological evidence suggests that it was at least three billion years ago, molecules based on the element carbon developed the ability of self-replication or reproduction. Furthermore, it seems certain that this required the presence of water. And, as they reproduced, for reasons unknown, but presumably following the mechanisms that I have already described, they diversified and were modified even further including, at some stage, developing a secondary "coding" aspect, which contained the instructions for their characteristics as an "organism," including such reproduction.

This code in turn is the origin of our DNA, and it is believed to have evolved into DNA via a number of different steps, including among them DNA's apparent immediate predecessor, RNA.

Also, these coding instructions, once they were established, were essentially fixed. They reached an equilibrium. All forms of life share the same basic set of DNA. Indeed, there is now mathematical evidence for why this is the case. It is possible that as early life evolved, alternative coding structures were tried. However, computer models have demonstrated that all such life forms would have been eliminated by those organisms with the most effective type. Further, this suggests that life on other planets, while it could have a DNA structure similar to our own, just as well could not.

There are many other unknowns associated with the development of life. The first is: what were the precise conditions in which such carbon-based molecules formed? The early earth was very different from what we know today, starting with its atmosphere. The atmosphere of the young earth had a far lower oxygen content, and this may have been a necessary part of the conditions for the establishment of life. For one thing, this atmosphere enabled a great amount of cosmic radiation to reach the earth, and such radiation might have been the trigger for its initial formation. On the other hand, there is speculation that the first life arose as a consequence of the volcanic activity at deep-sea vents, at the junction of continental, or tectonic, plates. But, until we actually see new life form, in such a location or in a test tube duplicating these or early planetary conditions, we cannot be sure of how it began - or, more accurately, of how it can begin.

Another perspective on this is that energy, in the form of light or heat, is also necessary for life's formation and its survival. In addition, as carbon is the residue of energy conversion - think of charcoal, so life as a carbon-based entity can itself be viewed as the outcome - or even as the process - of energy conversion. Furthermore, it is a strange coincidence that carbon, which gives us life, is in its purest, most symmetrical form, the hardest substance of all: diamond.

Basic unknowns

Even more, we do not know what happens at the quantum level: what causes, and comprises, the energy state transition from non-living to living, from inanimate to animate. Indeed, it may well be that this knowledge is excluded from us; that it represents a systemic limitation. It is likely that living organisms cannot perceive or understand the real beginning of life any more than they can of its end, of death.

Another significant unknown is: was there one initial formation, from which all life evolved, or many, somewhat simultaneous, developments, such as with varying DNA structures? Also, why has new life not continued to arise, even to the present day? The answer to the latter appears to be that any nascent life, or the chemical reactions that would initiate such life, would be oxidized in the current atmosphere. Indeed, this is the second contribution that the lack of oxygen in the early atmosphere made to enabling the formation of life. But, paradoxically, all life requires oxygen for respiration. Oxygen is a catalyst, and our survival requires its constant input.

Other evolutionary stages

There have been many other evolutionary signposts as well, the details of which are now the subject of scientific examination. Some of the more noteworthy of these include:

- The development of organism growth and motion, and thus the beginning of a complex life cycle.

- The processes of the migration of life from one environment to another, as from the deep-sea vents.

- The evolution of life into different kingdoms, now thought to number five or six, including, of course, plants and animals. What are the linkages between these kingdoms? For instance, did the first life forms evolve into plants, with such plants increasing the oxygen content in the atmosphere via photosynthesis, thereby enabling the evolution of animals? Or, was there a chaotic bifurcation from such primitive life, to both plants and animals?

- The increasing complexity of life: at the chemical level, the vast number of chemicals that organisms have learned to produce; at the system level, the wide variety of life systems that have evolved; and at the physical, structural level - for animals - the development of invertebrate and vertebrate, and the many "classes," among them mammals, birds, fishes, reptiles, amphibians, and arthropods, which is a phylum of many classes, including different types of insects.

- Next, there is the development of multi-phase life forms, including, for animals, those which experience a chrysalis stage or which hibernate.

- The development of "diploidy," or species that have two copies of each gene. Many species only have one.

- Related to this, and also to the distinctions between kingdoms, the development of different sexual structures, including asexual species, those with two sexes - including those which can procreate year-round versus those which do so only at a set time of year, and those with the ability to change sex.

One interesting question is whether the existence of only two sexes is also evidence of a chaotic bifurcation? Further, it is notable that sexual species have greater diversity in individual characteristics than asexual clones, and also that research has shown that it is the ability to create such diversity that gives sexual species an advantage in their ecological competition with asexual ones. Were it not for this, there would be no animals; only plants.

- Then there is the development of senses.

- The development of species that are positively linked, or symbiotic; which do not prey on each other, rather, which have evolved in tandem to help each other. Also, another example of "coevolution" comprises all of the species that have camouflage, either to facilitate their hunt, or to avoid being preyed upon.

- And lastly, there is the development of the brain, including - for humans, and a few other species - of the ability of reason and the perception of self-consciousness.

All of this is nothing short of amazing, and apparently only the result of will, and chance, and time.

Evolutionary links

I believe a basic evolutionary linkage might be as follows. To fulfill the instinct to survive, the first thing we had to develop was our sensitivity to pain, since this reflected a threat to our survival. Our first sense, then, would have been touch. From this we would have evolved movement, to avoid pain, and growth, to change such that a particular source of pain was no longer a threat.

The development of our other senses would have given us the ability to detect the possibility of pain, such that we could avoid it without first having to experience it. Also, through growth we would have learned how to impose pain ourselves. For example, we evolved our opposable thumb to escape sources of pain on the ground, including hunger - which could be eliminated by eating the fruit in trees, and then learned to use it to grasp a weapon. But then, seeing the consequences of weapons, we learned when not to impose pain. We evolved reason, and thence ethics, to control our desire to use weapons, and also to realize that there is more to life than pain.

We have only begun to understand what this last step entails, and where we can, and should, go from here. Indeed, there is no fundamental reason why life, including human life, will not continue to evolve for a long, long time to come. The universe is so large and complex - and young. Life will continue to find new ways to interact with it, and comprehend it. It is even possible that following some period of chaos a new kingdom, post-animal, will arise.