Life as One

Natural Selection Conserves Information

In the beginning, let us consider the primitive life. One requirement of the life is the existence of the death. It is the only known irreversible process in the laboratory. The irreversibility of the death is critical for natural selection [1]. Because the law of the entropy cannot be applied to the irreversible process, natural selection can drive the evolution. Furthermore, any information cannot preserve for a long time without natural selection.
Because the law of entropy is powerful, any copy of the information is incomplete. When, the accuracy of the copy is r, the accuracy of n times copy is rⁿ.

As n increases, rⁿ converges to 0. That is, if the copy is repeated, the data will be lost. According to the law of entropy, any information is gradually deteriorated, and eventually it is lost. The law of entropy is very powerful, but natural selection enables life to escape the law of entropy. The following is quotation from my knol [1].

Usually, natural selection works to preserve genetic information [2] . For example, histones, which bind to nuclear DNA, are very important proteins for survival. Because almost all amino acid changes are fatal in histone H4, variants of the peptide sequence of histone H4 are nearly always eliminated by natural selection. So the amino acid sequence of the histone H4 is almost constant during eukaryotic evolution. The famous example, the sequence of histone H4 differs only two sites in total 102 amino acids between pea and calf. It is assumed that animal and plant were diverged from the common ancestor about 1.2 billion years ago. This conservation of information is astounding. Continents have moved and geographic features have changed for 1.2 billion years. Any object could not remain on the surface of earth during the period.

So natural selection can conserve information.

The Importance of the Death

The irreversibility of the death is the requirement for natural selection. Why is the death of the life irreversible? Le us consider this problem. In the beginning, we shall regard a cell as the unit of the life. The cell acts as one unity. Each element of the cell is combined complicatedly. If a part of the cell is broken, it will try to repair the broken part. As long as it is living, it keep its internal environment stable. The property of a living organism is called homeostasis. Schroedinger says "It is by avoiding the rapid decay into the inert state of 'equilibrium' that an organism appears so enigmatic" [4]. Furthermore, he says as follow.

What is the characteristic feature of life? When is a piece of matter said to be alive? When it goes on 'doing something', moving, exchanging material with its environment, and so forth, and that for a much longer period than we would expect of an inanimate piece of matter to 'keep going' under similar circumstances. When a system that is not alive is isolated or placed in a uniform environment, all motion usually comes to a standstill very soon as a result of various kinds of friction; differences of electric or chemical potential are equalized, substances which tend to form a chemical compound do so, temperature becomes uniform by heat conduction. After that the whole system fades away into a dead, inert lump of matter. A permanent state is reached, in which no observable events occur. The physicist calls this the state of thermodynamical equilibrium, or of ‘maximum entropy'.

A cell keeps highly ordered structure. However, if it dies, homeostasis will be lost. The 3D structure of many proteins cannot be kept without homeostasis. Hence, a dead cell will be rapidly degraded. This fact is advantageous for living organisms because of two reasons. The first reason is that the degradation of the dead cell makes its revival impossible. The second reason is that other cells can easily reuse biological materials of it.
Furthemore, it is important that one whole cell dies as one unity. Because the whole cell dies cohesively, many important proteins simultaneously lost their function. If we want to revive the cell, we must reactivate almost all of them. The task is nearly impossible. Therefore, the death of the cell is irreversible.

Where Is the Natural Number?

Because the whole cell dies as one unity, the cell doesn't have the intermediate state between alive state and dead state. The cell has only two states: alive or dead. That is, the number of cells is digital data. Thus, we can use bacteria as the index of the environment. The different species of bacteria love different temperatures. For example, thermophiles in hot springs have different optimum growth temperatures. They form various colored structures. The colors are the indicator of the temperature [5]. In this case, the number of the specific kind of bacteria can be the indicator of the temperature. Since bacteria are countable, we can say that they digitize the environment. That is, a bacterium has properties of the natural number one. However, it isn't the natural number one itself. It has many properties, which the natural number one doesn't have. Especially, bacteria proliferate and die. The natural number one doesn't have these properties. Hence, we must abstract the natural number one from a bacterium.
An important problem arises here. What is the true natural number one? This problem had been profoundly discussed in ancient Greece. Among many opinions, the opinion of the Plato is widely accepted. The natural number one has three properties: indivisibility, invariability, equality [6] [7]. It doesn't have any sensible property. Among well known things, the data on the computer is close to the pure natural number. Consider one, which is data on the computer. It has no sensible property. We cannot see it. Instead, we can only see the numeric character "1" on the computer display. Furthermore it has three properties of the natural number one. It is indivisible, invariable and equal to each other. These properties are necessary condition for one as the data on computer. One must be permanent. If one changes to zero spontaneously, we will consider the computer out of order. Thus, one on the computer must be close to the natural number one for the human convenience. Especially, when we use the computer for the operation of the spaceship, the data of it must has close properties to the natural number one. That is, the digital information, which determine the life or death of a living organism, have the close properties of the natural number one [8].
Next question arises. Where is the pure natural number? Aristotle says that it is abstracted from various entities and it doesn't exist alone [9]. I think so. Perhaps, ancient Greeks didn't know the physical substance, which have no sensible property. Hence, Plato created Idea, which isn't physical substance. Probably, he might think that our thought isn't the physical substance. However, in the present age, scientists consider that our thought corresponds to electric activities of neurons in the brain. Now, scientists discovered action potentials of neurons correspond to the number [10]. The action potential itself doesn't have any sensible property [11], but it is obviously the physical substance. So, Aristotle's idea seems to be right. Then, the natural number one is abstracted. Because the language is necessary for the abstraction, we shall discuss about the language in the next section. 　

The Advantage of the Spoken Language

Let us consider the advantage of the language. Firstly, we shall think about the transmission of the technology of the hunting in the primitive age. Consider the transmission from a father to his son. He might show his son the hunting many times, and then he might make his son hunt. Next, he might point out faults of his son, make his son fix them. After repeating this process many times, his son would master the hunting technique. The transmission of it must be accurate, because it affect the survival rate of his son greatly. That is, it is the direct target of the natural selection. As mentioned earlier [1] [8], natural selection conserves it. Moreover, natural selection drive the evolution of it. Even so, the transmission takes long time, because this example is the analog information transmission. The difficulty of the transmission is the fault of the analog information.

In contrast, the communication by the language is fast and correct. Perhaps, the creation of the spoken language was the biggest revolution of the communication. Because the spoken language consists of indivisible phonemes, it is the digital data. That is, the phoneme has properties of the natural number one. The most prominent feature of the phoneme is the equality. A phoneme is equal to each other. This feature is the main advantage of the language. It makes the communication easy and accurate.

Finally, let us consider an example. Assume that a man met a tiger in the forest in the primitive age. He wanted to inform other persons of the fact. If before the invention of the language, he might try to imitate the sound of the tiger. Because the imitation is difficult, the sound couldn't be accurately transmitted from person to person. After the sound had been transmitted many times, it might be changed. In contrast, the communication with the language is easy and accurate. Because the word "tiger" is easy to transmit, it is hard to deteriorate during the repeated transmission. So, the advantage of the spoken language is obvious.

Categorization

The categorical perception is necessary for the language. Our speech is divided into discrete phonemes. Even though our speech sound is continuous, our brain dissolves the speech sound into discrete phonemes. The native speaker of a language can categorize the speech sound of the language into phonemes, which have the properties of the natural number one. That is, the particular part of the continuous sound corresponds to a discrete phoneme in the categorical perception. Examples of this type of the categorical perception are the color perception and the perception of the pitch.

Next type of the categorical perception is many-to-one correspondence. For example, the concept "dog" contains many kinds of dogs. There are variable size of dogs from the big dog "Saint Bernard" to the small dog "Chihuahua". There are various kinds of dogs. Thus, our brain extracts common features from various individual dogs and creates the category "dog". A category corresponds to a word. So, the categorization in various levels is necessary for the language.

Finally, we shall consider the creation of the natural number one. The action potential isn't the true natural number one. Moreover, there are no true natural number one in the real world. How did our ancestors develop the concept of the natural number one? Because every concept corresponds to the natural number one, we can abstract properties of the natural number one from every concept. Thus, the concept of the natural number one might be created.

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