Memory structures, like the brain and nervous systems, are evolved from matters that interact. This article looks at the evolution that leads to the development of memory structures in nature, and provides a context for biological memory structures. It looks at feedback interactions as the main driving force for such an evolution.
FEEDBACKS AND EVOLUTION
Feedback interactions drive evolution. Aspects of such interactions appear as stability, variation, and new orders of evolutionary. Negative feedback interactions produce homeostasis, stabilizing parts of interactive components as they evolve. Positive feedback interactions enhances divergence. It drives interacting components towards variations or even new orders. Human memory emerges from matters that interact in ways of positive and negative feedbacks. Here is a closer look at evolution.
Evolution is about changes, and patterns emerge from changes. Evolution of living things is first explained by Charles Darwin's (1809-1882) theory of Natural Selection, or Survival of the Fittest. Darwin's explanation is lacking in some areas that can be better explained by a theory of feedback interactions. The lacking areas can be the timeline of abrupt changes in the fossil records of species, the distinctive and diverse biological traits (e.g. body ornamentation like plumage or spots) of species not accountable by adaptation or natural selection (what is this nature that selects those traits?), and the phenomenon of reproduction. The act of self-reproduction is similar to the act of human memory in some respect.
Evolution aspect 1): Timelines of genesis in fossil records
picture: species, fossils, timeline of species change
Darwin proposes that changes of species over time are due to gradual mutation and natural selection. The natural environment selects which of the normal or mutated species to survive. This theory was probably based on Darwin's observations from domestication of wild animals, selective breeding by farmers/naturalists, and variations of the finches in the Galapagos islands. It was a vastly improved theory over creationism. Gerald Edelman uses this idea of Natural Selection to describe consciousness as something emerged from inter-activities among neuronal circuits, which is his TNGS theory.
There is one problem though. Natural Selection predicts that species should change gradually and steadily by mutations and adaptation. The fossil records however show that the timelines of change are not linear for species. Species hardly change at all for long periods of time, then change rapidly or become extinct in a relatively short period of time. The newly changed species will stay stable for a long time again. These step-like changes found in the fossil records contradict the theory of Natural Selection. Stephan Gould and Niles Eldredge published their theory of Punctuated Equilibrium to point out this flaw.
The theory of feedbacks provides a match for this data. The long stable periods where a species remains the same are dominated by processes of negative feedbacks between the species and the environment. Negative feedback interactions are homeostatic so the species doesn't change much. The short transitional periods where a species changes rapidly are dominated by processes of positive feedbacks, between the species and the environment. Positive feedbacks promotes divergence, resulting in rapid and major changes in the species and some changes of the environment.
Positive feedbacks can be triggered by cataclysmic events in the environment, like a big earthquake from progressively clashing tectonic plates, or mass migration/invasion of species to a new territory due to gradual or sudden weakening of barriers, or sudden loss of food source. They are short in duration because rapid changes will reach a level of saturation soon. Either it will burst into another cataclysmic change, a phase transition like that of birds living in South America to living in the Galapagos Islands, or reach equilibrium with the new changed environment in terms of mutual interactions (those Galapagos birds settled and became Darwin's finches). If it's gonna be a new phase transition, the transition will be short in duration also. They either find ways to fit in or drop out. If it's gonna be equilibrium, then it will last long periods of time, as negative feedbacks will naturally take over and keeping deviations caused by disturbances under check, till next major positive feedback kickstarts again.
Evolution aspect 2): Differentiation by adaptation.
picture: Galapagos finches (different beak sizes).
Random genetic mutations and random cross-breedings are factors of evolution, but that alone would point to continuous shades of variations in the result. That continuous variations doesn't match well with data, which shows very similar physical traits within a species but sharply different ones between species. Again the differences are stratified rather than continuous, like that in the fossil records. For this kind of differentiation, the Natural Selection theory explains it with adaptation to the environment.
Darwin noticed that the beaks of the finches on the Galapagos Islands are different from island to island, and concluded that such differentiation must come from adaptation to the varying conditions of each environment. The process of adaptation is somewhat vague according to Natural Selection. What exactly is the selector, and why is it selecting the way it does? Feedback theory explains this in a different way. The differentiation of beaks comes from an escalation of interactions. The change starts when the immigrant birds (finches) first arrive at a Galapagos island. Some of them make some behavioral changes to the local conditions of food sources and predators and mates. Those that don't change soon suffer consequences.
Natural Selection says the environment favors and keeps those "proper" changes in the species. Feedback theory says that some of the small changes get escalated into big changes by positive feedbacks. Some of the initial behavioral changes are rewarded with some advantages for the immigrant finches, such as a more efficient way of acquiring food. The advantages encourage the species to choose and reinforce those new interaction patterns (niches). It is active choosing and engaging on the part of the finches rather than them been passively forced upon by the environment. The behavioral changes are locked in with the material gains in positive feedbacks, which result in changes in the finches' physical traits. And one of the traits can be a new size and shape of the beak.
The environment around the immigrant finches will also undergo some changes. These changes in the finches and in the environment will reach a level of mutual balance. That is where changes escalated by positive feedback have become saturated, overtaken by negative feedback of checks and balances, and become homeostatic. And the changes manifested as newly acquired physical traits in the finches will stabilize, as well as changes in the flora and fauna around them.
It may take one or more generations of the immigrant finches to settle down to the new behaviors and physical traits. Somewhere along the way their offspring begin to inherit those acquired traits without going through the same adaptation process again. It's as if their body remembers what had happened before and repeats that. We now attribute this inheritance of traits to the genes since Gregor Mandel published his laws of genetic inheritance in 1866. But why and how do the genes do that?
Before there was the idea of genes, Jean-Baptiste Lamarck had theorized inheritance of acquired traits in 1801. Darwin's theory of evolution was published in 1859. They both took inheritance of physical traits for granted, as if that should happen naturally. But Gregory Bateson took an exception to that view.
Bateson argued that inheritance of acquired traits was unlikely because such inheritance would suffer a reduction of flexibility of the body to re-adapt. The offspring would have less adaptability to environmental changes because each physical trait was an efficient organization of cells that required those cells to loose some flexibility to reorganize. If newly acquired physical characteristics always get passed down to the offspring through genes, then the later generations may lose so much flexibility that they will be unable to re-adapt to an environment that will surely change again. That will lead to extinction of the species.
Nevertheless, physical traits do get passed down to later generations. If new traits acquired through adaptation get passed down by the genes, then the process of adaptation can change the genetic code, and that the changes in genetic code do not always exact a loss of flexibility for future adaptation.
Darwin remarked that if two generations of a species both acquired a new trait by adaptation, the offspring often acquired that trait around the same age or earlier as the parents. This timing phenomenon can be accounted for if genes are molecular structures that host sequential memories of somatic developments rather than somatic traits. The sequencing of that genetic memory will unfold to a same event at about the same time of development. And it can also address the inflexibility issue raised by Bateson. That is, with events of acquiring new a trait added to or modifying the genetic sequence, the expression of genes are still about movements and changes like cause-effect or relationships, instead of about results of change like size or color. The codes are verbs and actions instead of nouns and things.
The genes are molecules constructed and reconstructed during cell reproduction and metabolic cycles. Repeated reconstruction and rearrangement of genetic molecules are perhaps the reasons that ensure little or no loss of flexibility in the gene expressions (cellular activities) to re-organize. And adaptation depends on an organism's ability to reorganize itself at cellular level, in ways that accord with some parameters in the environment or within its own body. When there is a loss of flexibility for genetic materials to re-arrange cellular structures, that rigidity may have to do with the degrees of change in the environment and the inertia of genetic reproduction.
The environmental cycles of change are repetitively similar in general over many generations. And the reproduction cycles of the genes are also repetitive. There are connections between some parts of these cycles. If the external cycles in the environment are disrupted in a major way, the reproduction cycles of the genes can be critically affected as well, and may not be able to adjust fittingly to new rearrangements. That is one possibility of not being able to adapt.
Another possibility for loss of adaptability can be the gene reproduction process itself has become too narrowly confined, making the same kind of genes with the same range of ability to rearrange. The physiological problems of inbreeding are one example. The inheritance of acquired traits does not necessarily increase that rigidity. Rather, it is the responses and stimuli in the environmental become too repetitively similar, leading to the reproduction of genetic materials too narrowly similar also. What the organism needs is that the environment changes mildly and occasionally so that the rigidity of sameness does not settle internally. The pace of environmental changes should be neither too fast nor too slow, too much or too little. Then the reproduction of genes can have healthy flexibilities that accommodate various changes later.
There are two movements in the adaptation process of a species. The first is the movement of genes being reconstructed during cell division, followed by the genes synthesizing molecules that can interact metabolically. The second movement is metabolic interactions of the synthesized molecules. The metabolic interactions take place among the synthesized molecules (proteins), between the molecules and environmental inputs (pressures or stimuli or food), and between the molecules and the genes themselves. These two movements, of genetic rearrangements and metabolic activities derived from the genes, together account for an organism's ability to adapt, to acquire physical traits, and to pass that acquisition down to the next generation.
If we consider only the first movements of genes, then it may seem that all the information about adaptation is in the genetic code. That is not so. The second movement of metabolism is also indispensable to the adaptation process. In a narrow sense, the genetic code of DNA only reflects sequences and materials that can be used to synthesize metabolism-capable molecules in the body. It does not directly specify how the synthesized molecules will engage in metabolic activities that may or may not happen. Factors from the environment will partially determine an organism's metabolism. The sequences of genes will develop into one type of body trait if there are certain environment stimuli available at critical periods. They will develop into another type if certain environmental stimuli are absent at critical periods. These environment-dependent developments also influence how well a species can adapt later.
The more the genes can change stably under environment-dependent metabolic activities, the better the species can adapt. It is a feedback loop. Metabolic movements alter the reproduction of genes, and genes will incorporate information reflecting some of those metabolic changes. When a population with the same genetic changes reach a critical density, the children of that population will inherit those changes through genetic reproduction. It goes from adapting to adapted to inheriting. Inheritance of genetic changes enables the species to respond efficiently to those changes.
The changes in genes can be tested by comparing genetic samples before and after the adaptation of a species to a new environment. This comparison will be difficult because finding where the code sequence is altered is like trying to find someone in China without an address. But if the differences can be found before and after, and the differences can be similarly reproduced in other specimen undergoing similar adaptation processes, then that will establish the correspondence between physical change by adaptation and genetic changes in the DNA code.
The inheritance of acquired traits doesn't take hold in one generation after the traits first appeared. It takes many generations undergoing similar adaptation processes without a break before inheritance can firmly establish. During those generations, the density of genetic change in the population pool will become larger due to repeated adaptation behaviors. At some point the population density with changed genes will reach a critical level. The DNA segments reflective of that change will likely be present in both parents. And by reproduction, those genes get passed down to the children. And they don't need to go through the adaptation process anymore to possess the acquired traits.
The selective breeding of domesticated animals for specific traits similarly requires many generations. It is also to raise the genetic density of desired traits in the specimen's population, until the offspring can likely get those traits through recombined genes in breeding rather than through the selection process.
DIFFERENTIATION BY FEEDBACK INTERACTIONS
Differentiation by adaptation to environmental changes can be preserved through reproduction. Differentiation itself can take place in the physical traits as well as in psychological characters. Psychological differentiation such as having a particular outlook or preference can be driven by positive feedback interactions within the species, rather than between the species and the environment. An example of that can be found in religious affiliations.
The Protestants and Catholics emerge from a common Christian group that were homogeneous at first. Some circumstance led to a change of view in some members in regards to how to read and interpret the Bible. That change of view became a difference among members of the group. And that difference got amplified by symmetrical interactions - mutual rejections between members of opposing viewpoints. And the members branch off into rival subgroups. That led to the denominations of Protestants and Catholics.
The origins of different branches of buddhism, Judaism, Sufism have similar divergence development due to feedback interactions taking place internally. Such divergence development also takes place in politics. The U.S. became differentiated from England by interactions within the British Empire. There was an initial difference among individuals in the colonies and the empire regarding representations in government. The difference got escalated into a war that split the Empire into separate sovereignties.
Unlike physical traits, psychological differentiations are not inheritable through genes. Each person or group must acquire psychological traits through education and experience. So if the Protestants and Catholics do not keep reaffirming their versions of religious practice, their philosophical or religious differences will fade except occasional triggering by memory.
Evolution aspect 3): Complex Biodiversity. Bodily traits not due to adaptation or mutations (camouflage and ostentation - size, color, shape).
(picture) plumage of peacock, stripes of zebra, horn of rhinoceros. moss on tree bark
The diversity of lifeforms increases over time. This evolutionary trend is contrary to the direction pointed out by entropy, which goes from order towards disorder, heterogeneity to homogeneity. Living things evolve to become more heterogeneous and orderly (organized). Evolution produces more orders of species, and greater complexity in bodily forms over time. Some of these forms, like bio-mimicry (moss's camouflage) and ostentation (bird's plumage), are not direct results of adaptation or natural selection, because those that don't have such traits also survived. And nothing apparently can cause those forms to develop. Darwin knew of this.
Not just ostentations, Darwin also knew that some functions cannot be explained in terms of adaptation or Natural Selection either. He saw no environmental factors that could encourage or select something like the structures of eyes ranging from that of insects to that of mammals. And mutation cannot produce such coordinated structures either. Besides, how does an environment promote and select eye structures that can automatically adjust their focus and aperture, and only so in mammals but not in insects?
The conclusion is that evolution is not driven by adaptation and Natural Selection alone. But if not adaptation, then what may be the reasons for complex developments such as camouflage or ostentation or the eyes? One possibility is that it is from a combination of processes, which may or may not relate to the usefulness of those bodily forms, done willy-nilly in sequence, that has happened and that leads to the developments afterwards. The combination of processes happened because it could and did. The number of possible outcomes in the combination can double with each addition of factor. If the sequencing of those combination is repeated over and over, myriads of distinct and amazing patterns will emerge. Some of the patterns turn out to be the developments of camouflage or ostentation or eye structures.
In other words, complexity in biological forms can come from possible ways of combination of processes in addition to adaptation. Bodily traits such as zebra's stripes or rhinoceros' horns, bird's colorful feathers or moss's spots, human hairs on the head or autofocusing eyes, that may or may not have survival advantages, can all be results of some underlying processes combined willy or nilly together. Once those traits appear in some species, those that survive will proliferate and spread and pass on down those traits to the next generation. But that survival and proliferation do not prove that they are due to those traits. Similarly, those that don't survive may or may not be due to those traits either. The traits may help the species protect itself and gain food and reproduce, or they may not. Creatures with unfocused eyes may survive just as well as those with focused ones. Complex bodily traits can simply come from unforeseen combination of processes.
Examples of systemic complexity from combination of factors are plenty in other fields as well. They can be seen in chemistry, combinatorics (math), and even in fortune telling. Organic chemicals are far more numerous and diverse than inorganic chemicals, because they are formed by combinations of 4 elements - carbon, hydrogen, oxygen, and nitrogen atoms. Although these 4 elements are small in numbers, they are very flexible in how they can be combined. Inorganic chemicals include many more elements than the organic ones. But the limited ways of combination of those inorganic elements make the combined inorganic chemicals far less diverse than the organic ones.
A branch of mathematics called combinatorics is the basis for counting and probability theory. Combinatorics enumerates possible ways of combining a set of components. It reflects the complexity of a system based on the ways those components can be combined. For example, complex food recipes can come from combination of ingredients - mains, sides, and seasoning. In quantum mechanics, complex particles are combinations of various distribution probabilities of motions and charges.
(picture) hexagram in I-Ching, Taro cards, Organic chemistry
Fortune telling is a human example of using combinatorics to represent systemic complexity. In the West, astrology is a combination of planetary signs and tarot cards a sequenced stack of symbolic figures and scenes. In the East, the I-Ching (book of change) is based on hexagrams. From combination of respective elements, those divination systems produce symbolic representations that reflect complex life events.
Each hexagram in I-Ching is a combination of two trigrams. Each trigram has three yaos. So a hexagram has 6 yaos. A yao is either a solid or a broken line, representing a yang or a yin. Yang represents expansion or light while yin represents contraction or shadow, or something similar. Each addition of a yin or yang line can double the ways of representing a situation. Although possible to do so, I-Ching does not combine hexagrams into dodecagrams to make greater number of representations. But it does add more ways by allowing one hexagram to possibly transition into another. The transition depends on whether there is a kink in the casting of each yao line during the divination process. Commentary texts for each yao line and each hexagram provide people who tried I-Ching with insights into future events. Many have praised its divination power, just as others are impressed by the fortune-telling power of astrology and tarot.
In a similar fashion, feedback processes can be combined to produce many possible sequences and combinatorial outcome possibilities. Suppose positive feedback is p and negative feedback n. Possible combinations can be enumerated such as: n-p (negative-positive), p-p (positive-positive), n-n (negative-negative), p-n, p-p-p, p-n-p, n-p-n, n-p-n-p, p-n-p-p, etc. This combination can go on indefinitely. Put that into the context of biology, each combination may reflect a part of development of a trait.
Stable combination of feedback processes that survive may then manifest as distinct and perhaps surprising bodily traits. Traits will be orderly if they come from definite sequence of combination. What is in one body is very close to that in others, such as peacock's feathers or snake's forked tongue. If sequence of combination has some variations, traits may be orderly but in a partial way. What is in one body is similar to another when viewed broadly, but noticeably different when viewed closely. Such partial order can be seen in mottled pigmentation - the spots or lines or areas - in seashells, fish, cats, lizards, or pandas.
Pigmentation in albinos (all pale) or melanism (all dark) are like pure yin or pure yang hexagrams. They are rare cases among all possible ways of combinations. That oddity is not the same as skin pigmentations resulting from adaptation to prolonged environmental conditioning. People living in predominantly cloudy or sunny climates over many generations will develop pale or dark skins respectively. Those differentiated skin colors are reinforced outcome, whereas albinism is a probabilistic combination outcome.
Combination of processes can happen willy or nilly. If will is involved, the processes are initiated or cultivated by some order or pattern. The order may aim at some desirables, e.g. rewarding sensations like playing or eating or mating or exploring. Or it can be to get rid of some undesirable like fear or anxiety, or biased towards certain economic activities, or a combination thereof. If no will is involved, the combination is simply a chance happening that gets repeated. For example, an animal tries out a new diet for no reasons other than easy access or curiosity. Such activities may repeat because of easy availability or high likelihood, and become part of a sequence of activities.
NEXT
The 4th aspect of evolution is self-reproduction. It is about how self-reproduction emerges along with memory dynamics in evolution processes, and how matters change from the inanimate to living lifeforms. The next article will look into this in more details.
