Вадим Валерьевич Корпачев
Civilizations development and species origin technologies
1.2. SCIENTIFIC HYPOTHESES OF THE LIFE OCCURRENCE ON EARTH
There are a number of theories to explain the life occurrence on the planet that are difficult to prove their accuracy. A lot of these theories and their points to explain the existing species diversity exploit the same data but emphasize the data different aspects.
The assumption of spontaneous life occurrence was common in ancient China, Babylon and Egypt as an alternative to the divine creation of the world. Aristotle, on the basis of his own observations, joined all organisms in a continuous row. He stated that «Nature makes the transition from lifeless objects to animals with such a smooth sequence, placing creatures living without being animals between them so that one can hardly notice the differences between neighboring groups due to their close proximity». According to Aristotle’s hypothesis of spontaneous nucleation, certain «particles» of a substance contain a certain «active principle (source)», which can lead to the living organism’s creation. He falsely believed that source was also present in sunlight, mud, and rotting meat. With the spread of Christianity, the theory of the life’s spontaneous origin was not recognized with the spread of Christianity, but it continued its existence as an idea for many years.
According to the stationary state theory, Earth never occurred, but always existed and was always able to support life, and if it changed, the changes were very insignificant. Species also never occurred, they always existed, and each species has only two options − either its quantity change or extinction. Most of the arguments in favour of this theory are associated with inexplicable gaps in the fossil record. This theory is most precisely developed in this trend.
According to the panspermia hypothesis formulated by Herman Richter in 1865, life could have occurred one or more times at different times and in different areas of the Galaxy or the Universe. This idea was supported by G. Helmholtz, S. Arrhenius and W. Thompson were among this theory supporters.
S. Arrhenius believed that life did not occur on our planet, but was brought in by spores travelling through the outer space. After getting on a planet with suitable natural conditions, spores are transformed into cells, and cells give birth to life. S. Arrhenius having carried out calculations, in particular, proved the fundamental possibility of the bacterial spores transfer from planet to planet under the influence of the light pressure. The discovery of cosmic rays and the clarification of the radiation effect on biological objects have greatly weakened this hypothesis’s position.
Sankar Chatterjee, a professor of Texas Tech University and the University Paleontology Museum’s curator, having analyzed information about the early geological history of the planet and compared these data with various theories of chemical evolution, arrived at a conclusion that the simple life early forms occurrence on the planet would be impossible without the participation of comets and meteorites that fell on it. Organic compounds capable of the development of life’s launch were discovered in them during the study. This circumstance, to this or that degree, was taken into account by different authors of the life occurrence hypotheses. The fact of the organic substances in meteorites availability deserves special attention. According to the nuclear geochronology, their age stands for 4.6-4.5 billion years, which basically coincides with the age of Earth and the Moon. Hydrocarbons, carbohydrates, purines, pyrimidines, amino acids, i.e., chemical compounds that make up living matter constituting its base, have been found in meteorites. Also, more than a hundred different minerals have also been discovered. Furthermore, 20 minerals not presented in Earth’s crust have been found in the meteorites. Carbides, sulfides, etc. are among them. The proximity to the organic complexes composition of biological origin turned out to be so great that some authors suggested that living organisms were found directly in the very meteorites in the past. However, careful examination of organic compounds taken from meteorites has not confirmed the presence of optical activity, which indicates their abiogenous origin. At the same time, the data obtained demonstrated that the organic compounds’ formation in the Solar system on the early stages of its development was a typical and massive phenomenon. However, the outer space chemicals and most of the Solar system bodies do not have the complexity of living matter, as is observed on Earth.
Academician V.I. Vernadsky also adhered to the panspermia hypothesis. In his opinion, life in the Universe is spreading with the help light quanta. As for Earth, life could have occurred when a meteorite being a particle of other planet that disintegrated as a result of some kind of disaster hit our planet. The fragments of such a planet with bacteria or other microorganisms could go beyond the planet and get to Earth.
Fred Hoyle and Chandra Wickramasinghe, while studying the interstellar matter properties, noted that the cosmic dust’s infrared spectra are very similar to the organic matter’s spectra, to the dry bacteria, in particular. These scientists’ observations served the basis for putting forward the idea of the microorganisms’ possible existence in the interstellar space cosmic dust’s clouds. They suggested that within the period of 4.6−3.8 billion years ago, the life occurrence on Earth was the result of the microorganisms’ ingress from outer space. According to their calculations, a large number of space spores annually enter the upper atmosphere of Earth as the remnants of solid material scattered in the solar system. According to their ideas, comets are the life embryos’ carriers that were earlier formed in the interstellar space.
Francis Crick, the Nobel Prize winner for the DNA code discovery, also suggested in his book «Life Itself: Its Origin and Nature» (1982) that life on Earth did not occur by itself, it occurred through controlled panspermia, that is, through Earth’s deliberate colonization by microorganisms delivered on unmanned spacecraft by a developed alien civilization, which may have tried to perform terraforming for future colonization.
M. Sherman, a professor of Boston University, put forward the hypothesis of the «universal genome’s» artificial occurrence in Cambria to explain the causes of the so-called Cambrian explosion in the evolution of multicellular organisms. Moreover, he insists on the possibility of his hypothesis’s scientific verification.
In favour of their views, supporters of the panspermia hypothesis provide two indirect evidences in favour of their views: the genetic code universality and the need of molybdenum availability for the normal metabolism for all living creatures, which is currently extremely rare on the planet. Supporters of the comet panspermia theory deny the life spreading from one planet to other one process’s controllability, and suggest its spontaneity and chance.
Taking into consideration the fact that the life spontaneous occurrence’s probability on Earth is extremely negligible, the panspermia hypothesis is the most real in comparison with both the evolutionary theory and religious beliefs. Its disadvantage is that it does not explain how and where the first microorganisms to come to Earth were formed; it only indicates the other place where it could have occurred, but does not explain the process and the reasons for the given occurrence.
1.3. THE EVOLUTIONARY THEORY
The evolution theory is highly ranked in the study of the history of the origin of life on Earth. Jean-Baptiste Lamarck was the first to identify two most common trends of the life on Earth’s development: the upward development from simplest forms to more complex and advanced ones and the adaptations’ formation in organisms depending on environmental conditions (vertical and horizontal development). In his works, the scientist noted the organisms’ historical development, which is not of random but of regular nature and occurs in the direction of gradual and steady improvement. He believed that the organisms’ development is not a spontaneous process. In his opinion, «the nature’s drive for progress», «the drive for perfection» was originally inherent in all organisms and laid down in them by the Creator. He argued in his paper «Philosophy of Zoology» that subsequent generations are able to inherit acquired useful properties thus forming new species. For example, in his opinion, giraffes generated from antelopes due to the constant extension of their necks when they tried to reach the leaves on the tops of trees.
Ch. Darwin, being inspired by similar examples, continued the Lamarckian series of assumptions. In his book «The Origin of Species through Natural Selection,» he revealed the main organic world’s evolution factors. Approximately at the same time, Alfred Russel Wallace published an article entitled «On the Law Which Has Regulated the Introduction of New Species», in which he came up with the idea of «survival of the most adapted ones».
Ch. Darwin grounded the theory of the gradual evolution of some species into other ones under the influence of such factors as the survival of the most adapted, the struggle for existence, natural selection, and adaptability to environmental conditions.
The essence of evolutionary doctrine lies in the following main points:
1. All the living creatures’ types that inhabit Earth have never been created by anyone.
2. Having occurred in a natural way, organic forms slowly and gradually transformed and improved in accordance with the surrounding conditions.
3. The species’ transformation in nature is based on such organisms’ properties as heredity and variability, as well as natural selection constantly occurring in nature.
4. Natural selection is carried out through a complex interaction of organisms with each other and with factors of inanimate nature; Ch. Darwin called this relationship a struggle for existence.
5. The adaptability of organisms to their living conditions and the diversity of species in nature is the result of evolution.
According to the mentioned above provisions, a variety of species possessing new specific features allowing a better adaptation to the environment (habitat) can be formed within each species. If the newly acquired qualities are inherited, then genetic differences are amplified in subsequent generations due to the selection of properties that ensure the genotypes’ survival and the new mutation’s accumulation. The mentioned above variety of species adapts better to existing conditions, phenotypically moving away from the parent species. Intraspecific competition leads to the deliberate (selective) removal of the least adapted to the environment individuals and an increase in the number of individuals whose properties favour the survival and reproduction in this habitat. According to the evolutionary theory proponents, such a natural selection is the main mechanism for the new species’ occurrence. Evolution is a process of long-term and gradual qualitative changes that ultimately result in the new species’ occurrence.
According to some evolutionary theory’s advocates, the palaeontological, biogeographic, systematics, plant and animal breeding, morphological, comparative embryology and comparative biochemistry data confirm the evolutionary occurrence of species through natural selection, although they are not indisputable evidence. Three groups of facts are used to confirm the theory. The first group represents examples of species’ minor changes observed within a geologically short period of time in the wild nature, as well as the results of agricultural plants and domestic animals’ breeding. The second group is the fossil record, which indicates a significant variability of life throughout the history of Earth. The third group of evidences deals with the similarity of the morphological features of the all organisms’ structure, which may indicate their common origin. All explanations of the facts discovered are reduced to a spontaneous random process without any intellectual interference in the programming system.
Charles Darwin formulated his theory of evolution in accordance with the morphological and physiological characteristics, using the natural selection ideas, but did not determine the source of variability in the population. A synthetic theory of evolution combining the Darwinian natural selection’s idea with the laws of heredity and population genetics was developed in the middle of the last century. Currently, it is the most developed system of ideas regarding the speciation’s processes. The hypothesis of the new genes’ recessivity was the impetus for its development; according to it mutations constantly arise in each reproducing group of organisms during the gamete maturation as a result of errors in the DNA replication. Therefore, the mutation process is the most important evolutionary factor, and the bulk of evolutionary material is represented by various forms of mutations, which are manifested by means of changes in the hereditary properties of organisms that occur naturally or are caused by artificial means. After the different types of isolation’s occurrence between populations, they begin to evolve independently, and as a result, genetic differences are gradually accumulated between them, and with time genetic incompatibility is achieved, and crossing becomes impossible.
Julian Huxley, the English biologist and naturalist, indicates in his famous book «Evolution: The Modern Synthesis» (1942) that the species is a system of populations that are reproductively isolated from other species’ populations, and each species is ecologically isolated; speciation lies in the genetic isolating mechanisms’ occurrence and is carried out mainly in conditions of geographical isolation. According to the J. Huxley’s ideas, reproductive isolation is the main criterion that indicates the speciation’s completion.
According to the synthetic theory of evolution, the formation of new species occurs as a result of the separation of individuals of one species into groups that do not interbreed, and the very evolution is defined as the populations’ genetic structure change over time. The allele’s frequency changes thus becoming more or less common compared to other forms of this gene. The acting evolution forces lead to changes in the allele frequency in this or that direction. The change disappears when the new allele reaches the fixation point − it completely replaces the ancestral allele or disappears from the population. Mutations increase the population’s variability due to the emergence of new genes’ allelic variants − mutational variability. If any allele increases the organism’s adaptability more than other ones of the given gene, then the share of this allele in the population will increase with each generation, i.e., selection takes place in favour of this allele. Evolution through the natural selection is a process in which mutations increasing the organisms’ adaptability are fixed. As a result, three processes are necessary for the evolution’s implementation: mutational (to generate new variants of genes with a low phenotypic expression); recombination (to create new phenotypes of individuals), and selection (to determine the compliance of these phenotypes with the given living conditions or growth).
Judging by the palaeontological chronical and by the mutations’ speed indexes, this concept advocates believe that it takes in average 3 million years to reach the complete incompatibility of genomes, which makes crossing impossible. Therefore, it is a rear event to witness the new specie’s formation in natural environment.
In addition to mutational, there is also the combinatorial variability distinguished, which is determined by recombination, but it leads not to the allele frequencies’ changes but to their new combinations.
The gene drift is one more factor contributing to the allele frequencies’ changes.
The synthetic theory of evolution differs from the Ch. Darwin’s evolution in the following points:
1. It distinguishes a population in which the same species individuals are able to interbreed, and but not an individual or a separate species.
2. It considers a steady change in the population genotype’s change the process of evolution.
3. Mutational processes and isolation are treated as the leading factors.
4. The mutational and recombinative variability are the material for evolution.
5. Natural selection is considered as the main reason for the adaptations and speciation’s development.
In accordance with the synthetic theory of evolution speciation is a time-consuming process. However, J. B. S. Haldane found a discrepancy between the real speciation speed and the expected one based on the population genetics models (Haldane’s dilemma) by means of mathematical calculations. He published an article «Cost of Natural Selection» on the basis of his research in the «Journal of Genetics» scientific edition. D. Haldane calculated the mathematical relationship between the intensity of selection and rate of the existing alleles’ substitution in the population by other, more adapted ones. He also evaluated the mortality rate caused by the positive natural selection, while maintaining the mutant gene. According to his calculations, the speciation would have taken much more time for the stage-to-stage formation than it has actually taken (according to the paleontological data) for the implementation of speciation would require much more time than is actually observed (according to palaeontological data).
Later, M. Kimura, while studying the rate of amino acid substitutions in proteins, found that for mammals the substitution rate for the genome per generation was several hundred times higher than the Haldane’s estimation. Kimura showed that in order to maintain a constant population size while preserving mutational substitutions, the rate of occurrence of which stands to one substitution in two years, each parent should produce 3.27 106 descendants so that one of them survives and begins to breed. The mismatch of this impressive number with real data served as the basis for the «Neutral Molecular Evolution Theory» development.
Another argument in favour of this theory’s development was the fact that the assumption regarding more frequent occurrence of favourable mutations (in reality, such mutations are rather rare compared to the adverse ones) was necessary in order to explain the molecular evolution rate provided it proceeds under the natural selection influence.
The «neutral evolution» hypothesis’ main content lies in the point that majority of the changes at the macromolecular level are not controlled by natural selection as Darwin’s theory states, but are determined by the random drift of neutral mutations. According to the authors, this theory is proved by a number of direct and indirect arguments. At the same time, the neutral molecular evolution theory does not turn down the role of natural selection in the development of life on Earth, but emphasizes the proportion of mutations that possess adaptive significance. This theory has demonstrated that the processes associated with speciation are still far from a final explanation based on population-genetic models.
Modern synthetic theory of evolution has a number of disadvantages. It makes no distinction between macroevolution and microevolution, considering one the continuation of other one on a larger scale. Such view’s advocates have detected genetic changes from the population’s original composition from generation to generation, in various laboratory scientific experiments, including the model organisms’ development (drosophila, mice, and bacteria). It gave the grounds to assume that both microevolution and macroevolution are based on the same mechanisms and, in their view, minor changes can lead to significant ones over time, but the authors provide no evidences to prove it. Experts have no doubts regarding the microevolutionary processes within the species, for example, the hair colour or skin colour change, the beak shape, etc., due to which many types of breeds and sorts can exist within the same species. However, microevolution is determined by the alleles frequency’s change in a population (i.e. genetic variability due to such processes as selection, mutation, genetic drift), while the macroevolution involves changes at the species level or higher.
Fred Hoyle argued in his books «The Intelligent Universe» (1983), «Mathematics of Evolution», «Evolution from Space» (1981) and «Why Neo Darwinism Does Not Work» (1982), that the calculation results state that the Neo-Darwinism theory either does not work at all, or works only partially. Many of the common arguments that biologists use to confirm evolutionary theory turn out to be doubtful.
Academician Yu. P. Altukhov (Алтухов Юрий Петрович), a Director of the Russian Academy of Sciences’ Institute of General Genetics named after N. I. Vavilov, the «Successes of Modern Biology» journal editor-in-chief, points out in his book «Genetic Processes in Populations» (2003) criticizing the synthetic theory of evolution:
«In any case, it is becoming more and more obvious that evolutionary consequences are not necessarily concluded from the results of a study of both natural and experimental populations with their systemic organization taken into account. On the contrary, it confirms once again that the genetic variability of the simplest populations, traditionally regarded as the evolutionary process’s elementary units, is nothing but a stabilization mechanism for the species’ hierarchical, historically formed structure. Such a conclusion contrasts with the population genetics’ tradition, which has always been focused on the dynamics of populations, identifying it with the very evolutionary process».
However, the synthetic theory of evolution still remains the only scientific model to explain the known facts of the species’ origin and development. At the same time, the contradictions accumulated require the development of other theoretical concept of the of life occurrence on Earth.