Shortly after the earth was formed some four and a half billion years ago, the rudiments of life began to emerge. Replicating molecules, similar but less complex than DNA, must have been the initial step on the road to life. It's even debatable whether or not one could term such chemical compounds as living. They did, however, possess the ability to make copies of themselves and so continue their existence. As in any from of evolution, the molecules more able to do this in the prevailing environmental conditions became successful at the expense of less able molecules. Eventually, as with any replicating system, the most successful breeders will proliferate. As with giraffes mentioned earlier, there will be a distribution of variants within each type. Once such systems took a hold, they continued to exist unless the environment changed to an extent that even the widest of their variants was unable to survive. Perhaps life formed many times only to be destroyed when cataclysmic events took place on earth, but by the first one thousand million years, the planet had settled sufficiently for life to continue existing. It wasn't much to speak of—for most of its existence on earth, life has predominately been of the one cell variety. Evolutionary changes were painfully slow with nothing obvious happening over hundreds of millions of years, but they did occur, allowing for the explosion of life that has taken place over the last five—hundred million years.
On the face of it, the genes that carry information seem to be purposeful creatures, intent on their own survival at the expense of others, their inherent will to survive being the most important facet. It would almost seem as if they are intelligent entities. This is an illusion. Genes don't think and only appear to be purposeful. We, and other forms of life on this planet, are the ones possessing the will to survive (consciously dominant in ourselves at least) because the simple reason is that we have in our genetic makeup genes that promote survival. The arrival of the survival gene was a significant part of life's history along with the genes that communicated variation in species.
Very early life forms may have been extremely uniform with little or no distribution of traits. Of course, some variation would occur naturally, as a result of the laws of physics. On small scales, quantum variations ensured that no individual life form would be a perfect likeness to any other but these variations might not have been enough. A colony of cells, all exactly alike would not have possessed the variation necessary to cope with changes in the environment. Put another way, if all giraffes had necks exactly the same length, there would be no distribution curve as described earlier. There would be only a solitary narrow peak on the graph. Now, if trees were only a centimetre or two above the height of the giraffes’ heads, the giraffes would quickly become extinct because they lacked the ability to adapt. If certain genes that promoted variation to exist were formed, the species that contained such genes would very quickly take over while the non-variation genes in other species would die because they couldn't cope with new conditions.
DNA, as we know it, has similarities across the entire spectrum of life on this planet. It is composed of four base pairs, c g t and a—All genes, all variety, is essentially a variety of these four bases. It has always been a quandary why DNA is like this and why other DNA molecules containing different bases do not exist. The answer is probably threefold: the molecule was unstable and simply broke up; it had no capacity for variation; or, it had some capacity for variation but not as much as our DNA and consequently could not compete.
The other important change was the introduction of the survival gene. Before nervous systems evolved in animals, reaction to the environment took place mainly by the way of a chemical response. Nervous systems are an improvement on the same thing and the animals possessing them communicates with the environment better than those not possessing them.
Neurone cells can transmit electric impulses or thoughts. Early life with clumps of neurones in the form of a primitive brain certainly was not able to think. Consciousness was millions of years away at this stage. Eventually, a gene responsible for a basic instinct of survival appeared. This manifested in primitive brains to enable them to react to danger. Many other animals, of course, could have evolved to avoid danger simply by variation in their species. For example, a plant leaf may adopt a certain colour or appearance so that it isn't eaten. This is not a conscious decision on the plant's part: it is simply the profligation of non-edible variants. Different from this is the basic will to avoid being eaten and the subsequent trigger of a function to continue this avoidance. Once a sufficient nervous system existed and once the base instincts evolved by way of survival genes, life was ready for an immense explosion. This took place in the Cambrian era about six hundred million years ago.
This again is not the conscious will of genes themselves. Instinct or will is a by—product. Early creatures that developed the survival gene would, of course, survive better than those who didn't have it. It was a very successful gene, evidently so because it is still here in some form or another. This is an important concept: it is the action of a chemical group, i.e. a gene, on a bunch of cells imparting on them the ability to “think". Many years later, this and other genes would impart the ability for our ancestors to adopt conscious thinking and a whole gamete of thought processes and emotions. Beings would actually be able to consciously think of their own survival and make choices as to how this should proceed. Some indeed say that life only appeared on this planet when the conscious ability to contemplate itself arose. In this case, life is a recent phenomenon on planet earth: what existed before was merely a replicating system.
These were two very important changes for the survival of life. The first allowed variation to exist and this variation allowed the appearance of survival genes. So it's then possible to see why genes don't think and that they are the mirage of purposefulness. It's they easy to anthropormorphize evolution, that is to give it human characteristics. We do this when observing, say, cats or dogs, delighting in their apparent mimicking of human actions, while what goes on in their heads may be entirely unrelated to this. The idea of the “Selfish Gene” is an anthropomorphism.
So to recap, evolution is a complex matrix of possibilities where environment decides outcome. An unchanging environment doesn't promote evolutionary change. We imagine evolution to be purposeful, forever becoming and producing more complex organisms but it doesn't have to be like this—devolution can happen too.
Another important factor in evolution is the number of species existing in a biosphere. Life on earth is an exceedingly complex system of food chains. These food chains are often interlinked. Imagine a planet where life evolved with only a few species in a solitary food chain. It doesn't matter if millions upon billions of each species existed, if something happened to one, say, by a change in the environment, the others would be badly affected too. If this was the base species, i.e. the one on which the others fed, probably vegetable in nature, then the others would go extinct and life would cease to exist on the planet. We are lucky that many food chains exist on earth and substitutes are available if one food expires. There may come a time when environment changes are just too much and the entire system on earth collapses, but in the meantime the number, variety and complexity of species acts as a buffer to maintain a viable biosphere. The more species existing then the greater the buffer, giving us a reason to ensure that our negligence does not needlessly deplete the pool even further and so put in jeopardy our own survival.
Another important point about the number of species living in a biosphere is that the more species in existence then the greater the evolutionary change. It may be the case that the physical environment remains unaltered but the biological environment will be in continual flux as competition between species promotes further complexity. If only a few species existed on a planet and no physical change was going on, the species would very quickly achieve a balance unlikely to alter unless something drastic happened to the environment. With hundreds, thousands and more species, the system is immensely complicated, more so than would be solvable with
the largest computer. Compare this to the three-body problem in physics where it's impossible to calculate the outcome of three separate gravitational sources interacting with each other? Thousands of species in a biosphere defy description. In this case, outcomes are usually governed by chaos theory—in other words, they are chaotic in nature and we haven't a clue as to what's going on. Attempts by man to adjust the balance of nature are often disastrous. This chaotic system existing in a complicated biosphere means that there is always something going on; a movement here, compensated by another somewhere else which in turn adjusts a dozen other factors, all leading to evolutionary change.
One argument often raised when evolution is discussed is the division of life into different species. Where it is quite easy to see how varieties evolve within a species, the evolution of separate species is more of a problem to illustrate. Take dogs, for example. We now have many breeds from Alsatians to bloodhounds and terriers. They have evolved from a common source over a relatively short period of time but only because the breeding environment has been controlled by man. It's still possible to mix breeds of dogs, as any mongrel will tell you. However, left to their own devices without the influence of man, most breeds eventually revert back to their original form, a happy coincidence when considering some of the unfortunate creatures the kennel club wish to preserve. Cats are the same and, left alone, the breeds would disappear too, but cats and dogs being different species are unable to naturally breed together. The reason that separate species evolved in the first place was that evolution wouldn't take place without them. If originally all life was of the same species then there would possibly be variety but no diversity and capacity for change would be very limited. As mentioned, the more species existing then the greater the chance that life has for continued existence on a planet. A food chain with only one species is a non-starter. However, with geographical separation, physical contact between varieties would be at a minimum and over extended time, the creatures, evolved in different environments with changes to DNA from random fluctuations, would be related but probably unable breed successfully together. They may not be totally unable to breed but in a competing society unions between animals that are near to being 100% capable of producing offspring will quickly outperform unions with even 80% success rate. Fecundity would always favour the more successful unions and after time, even with the groups together, separation into species would continue until the percentage of successful unions between them would be reduced to almost zero.
What sort of geographical separation causes different species to appear? Migration of animals over terrain separates groups of them into different regions which could then evolve separately. However, more obvious is the process of continental drift which has been occurring for millions and billions of years. Driven by thermal currents, continents drift over earth's surface. For example, a volcanic ridge running north / south through the Atlantic is pushing the Americas and Europe / Africa apart. When Africa separated from South America, species on each side were initially similar but evidence has showed that divergence of species took place thereafter, thus giving each continent its own unique variety of life. But the process doesn't have to be so enormous. Even the presence of a wide river, such as the Congo, can separate a species into two further distinct species in the future.
There was an evolutionary choice early in the history of life. Sexual reproduction was a long time coming but once it arrived, an explosion of species happened. Save for existing, single cell life spent eons doing little on earth. Varieties would be limited and separation into species would be limited too but when life eventually became more diverse and better able to reproduce, by sexual reproduction, a watershed stage was reached.
Geographical separation may not have amounted to much. Perhaps different pools with different salinity levels were all that was necessary for different species to emerge. Where the life form hadn't much mobility, even a meagre separation would be sufficient. Dogs and cats are mobile and left to their own devices, they would probably revert not to a single type but to several types that became suited to their particular environments be it grassland, woodland or city streets. Millions of years of separation would probably turn them into separate species unable to breed together. Some insects are quite mobile and can move across continents but others aren't. They seem to remain in a specific and favoured locality. When insects evolved and spread over the earth, the moving process would largely be gradual but, having short life cycles, evolutionary changes are quick. Compare the life of an ant to an elephant? Separation into species and even the subsequent mixing of these species, now unable to breed together, creates the hodgepodge of species we see today. Is it any wonder then that small and quickly reproducing life forms like insects can produce many more species, thousands of times more in fact, than mammals or birds?
The argument over human origins is also put to rest by following the above reasoning. Some expound the theory that mankind spread around the planet after emerging out of Africa some quarter of a million years ago. Skulls of various representatives have been found in Peking, Java and so on. They then evolved independently to become the basis of the population we have today. Evidence suggests that there was a later migration from Africa but this, it is attested, was only an addition and not a replacement. The majority favour the following hypothesis: the latest migration, of which we are all a part, moved out to supplant the other hominoid people who eventually became extinct. It is likely, considering the earlier people had been separated such a long time in different environments from each other that they had become genetically separate, if not complete separate species. (there is some evidence, however, for interbreeding between Neanderthals and ourselves) The new race, more intelligent and more able to adapt, found that the other races were not genetically viable for them to mix with, and, being separate, the selfish gene attitude that we all possess guided us into remaining within our own groups.
The process of evolution as described above has had a marked effect on the psychology of human beings. The biologist Richard Dawkins put forward this idea of the selfish gene in his book of the same name. In it he describes the effects of the gene's apparent will for survival. This will, of course, is a manifestation of our own minds and genes are themselves only chemical messengers, but the effect is there nonetheless. We and other animals possess a will for survival, excepting lemmings on a bad day (actually a myth), and this is demonstrated in our psychology of reacting with other groups and individuals.
Reacting with other groups and individuals takes on a whole new meaning where alien life is concerned. We now leave the earth and compete in a cosmic arena where one product of evolution clashes with another. In this arena, it is very likely that there will be casualties.
* * *
Appendix
Extending Life
Most cells in the body work in close co-operation with their neighbours and therefore respond to contact and chemical mediators (acting at close or long range) in order to inhibit cell division and allow the formation of specialised (differentiated) cells. Differentiation occurs by switching on and off the required genes in the required sequence thus allowing the formation of specialised cells which in turn produce the various specialised tissues and organs. When the inhibition of cell division is overcome, as in cancer, the cells start to divide and become progressively invasive as more of the cellular control mechanisms are surmounted. To give an illustration, if human phagocytes are removed from the lung and are placed in the appropriate culture media they will start to divide and spread across the culture plate until they form a confluent monofilm—at which point they stop dividing. On the other hand, some cancer cells, for example, HeLa cells removed from a lung cancer patient many years ago are still in culture today and it is said that there is more of Helen Lane today than when she was alive. These types of tissue culture cells have been termed immortal cell lines. But of course these cells could not reform lung tissue because they would not co-operate and reproduce rec
ognisable tissue and they would not be able to function properly because they would have lost certain biochemical processes ( i.e. cancer cells tend to de-differentiate and become more embryonic in nature).
So in future, the difficulty is likely to be regaining control of the cells released from inhibition and re-stimulating and directing the correct form of differentiation.
Secondly, the brain. We are born with more or less our full complement of 100 billion nerve cells (neurones). The majority of connections between the neurones (via synapse formation) occur after birth with most being formed by the age of ten but apparently we can add and remove these connections throughout life. The connections made between nerve cells depends to some extent on the experiences gained by the individual.
At birth, the brain weighs 25% of that of the adult brain and by the age of 3 years this percentage has risen to 90%. This increase is due to the division of the support cells—the glial cells. The glial cells are responsible for amongst other things the production of the myelin sheath—a complex membrane, which wraps around the nerve cell and allow impulse conduction at up to 200 mph.
Alien Psychology Page 21