The history of the development of our planet is studied by almost all sciences, and each has its own method. Paleontological, for example, refers to the science that studies long past geological epochs, their organic world and the patterns that occur during its development. All this is closely connected with the study of the preserved traces of ancient animals, plants, their vital activity in fossil fossils. However, each science has far from one method of studying the Earth, they most often exist as a set of methods, and the science of paleontology is no exception.
Science
To better navigate the terminology, before getting acquainted with the paleontological method, it is necessary to translate the complex name of this science from Greek. It consists of three words: palaios, ontos and logos - "ancient", "existing" and "teaching". As a result, it turns out that the science of paleontologyrestores, clarifies, studies the conditions in which long-extinct plants and animals lived, explores how ecological relationships developed between organisms, as well as the relationship between existing organisms and the abiotic environment (the latter is called ecogenesis). The paleontological method of studying the ways of the planet's development concerns two sections of this science: paleobotany and paleozoology.
The latter studies the geological past of the Earth through the animal world that existed in those eras and is divided, in turn, into paleozoology of vertebrates and paleozoology of invertebrates. Now new modern sections have also been added here: paleobiogeography, taphonomy and paleoecology. The paleontological method of studying the Earth is used in all. Paleoecology is a section that studies the habitat and conditions in it with all the relationships of organisms of the distant geological past, their changes over the course of historical development under the pressure of circumstances. Taphonomy explores the fossil state of organisms in the patterns of their burial after death, as well as the conditions for their preservation. Paleobiography (or paleobiogeography) shows the distribution of certain organisms in the history of their geological past. Thus, it turns out that the paleontological method is the study of the process of transition of the remains of plants and animals into a fossil state.
Steps
The preservation of fossil organisms in sedimentary rocks in this process contains three stages. The first is when organic residues accumulateas a result of the death of organisms, their decomposition and destruction of the skeleton and soft tissues from the action of oxygen and bacteria. Demolition sites accumulate such material in the form of communities of dead organisms, and they are called thanatocenoses. The second stage in the conservation of fossil organisms is burial. Almost always, conditions are created under which the thanatocenosis is covered with sediment, which limits the access of oxygen, but the process of destruction of organisms continues, since anaerobic bacteria are still active.
Everything depends on the speed of burial of the remains, sometimes sedimentation moves quickly, and burials change little. Such burials are called taphocenosis, and the paleontological method explores this with much greater effect. The third stage in the conservation of fossil organisms is fossilization, that is, the process of turning loose sediments into solid rocks, in which organic remains simultaneously turn into fossils. This happens under the action of various chemical factors, which studies the paleontological method in geology: the processes of petrification, recrystallization and mineralization. And the complex of fossil organisms here is called oryctocenosis.
Determining the age of rocks
The paleontological method allows you to determine the age of rocks by examining the fossils of the remains of marine animals that have been preserved through the process of petrification and mineralization. Of course, one cannot do without classifying the types of ancient organisms. It exists, and with its help, prehistoric organisms found in the rock mass are studied. The study takes placefollowing principles: the evolutionary nature of the development of the organic world, the gradual change in time of non-repeating complexes of dead organisms and the irreversibility of the evolution of the entire organic world are traced. Everything that can be studied with the help of paleontological methods concerns only long-gone geological epochs.
When determining patterns, it is necessary to be guided by the most important provisions that provide for the use of such methods. Firstly, in the sedimentary formations in each complex there are fossil organisms inherent only to it, this is the most characteristic feature. Methods of paleontological research make it possible to determine the strata of rocks of the same age, since they contain similar or identical fossil organisms. This is the second characteristic. And the third is that the vertical section of sedimentary rocks is absolutely the same on all continents! It always follows the same sequence in the succession of fossil organisms.
Guide Fossils
The methods of paleontological research include the method of guiding fossils, which is also used to determine the geological age of rocks. The requirements for guiding fossils are as follows: rapid evolution (up to thirty million years), vertical distribution is small, and horizontal distribution is wide, frequent and well preserved. For example, it can be lamellar-gill, belemnites, ammonites, brachionodes, corals, archaeocyates, etc.similar. However, the vast majority of fossils are not strictly confined to a certain horizon, and therefore they can not be found in all sections. In addition, this complex of fossils can be found in any other intervals of the same section. And therefore, in such cases, an even more interesting paleontological method of studying evolution is used. This is the method of guiding sets of forms.
Forms can be completely different in meaning, and therefore there is also a subdivision for them. These are controlling (or characteristic) forms that either existed before the time being studied at a given moment and disappear in it, or exist only within it, or the population flourished at a given time, and the disappearance happened immediately after it. There are also colonial forms that appear at the end of the time under study, and by their appearance it is possible to establish a stratigraphic boundary. The third forms are relic, that is, surviving, they are characteristic of the previous period, then, when the time under study comes, they appear less and less and quickly disappear. And recurrent forms are the most viable, since their development at unfavorable moments fades, and when circumstances change, their populations flourish again.
Palaeontological method in biology
Evolutionary biology uses quite a wide variety of methods from related sciences. The richest experience has been accumulated in paleontology, morphology, genetics, biogeography, taxonomy and other disciplines. He became the very base, withwith the help of which it became possible to turn metaphysical ideas about the development of organisms into the most scientific fact. The methods of general biology were especially useful. Paleontological, for example, is included in all studies of evolution and is applicable to the study of almost all evolutionary processes. The greatest information is contained in the application of these methods about the state of the biosphere, it is possible to trace all stages of the development of the organic world up to our time by the sequences of change of faunas and floras. The most important facts are also the identified fossil intermediate forms, the restoration of phylogenetic series, the discovery of sequences in the appearance of fossil forms.
The paleontological method of studying biology is not alone. There are two of them, and both deal with evolution. The phylogenetic method is based on the principle of establishing kinship between organisms (for example, phylogenesis is the historical development of a given form, which is traced through ancestors). The second method is biogenetic, where ontogenesis is studied, that is, the individual development of a given organism. This method can also be called comparative embryological or comparative anatomical, when all stages of development of the studied individual are traced from the appearance of the embryo to the adult state. It is the paleontological method in biology that helps to establish the appearance of relative signs and track their development, apply the information received for biostratigraphy - species, genus, family, order, class, type, kingdom. The definition sounds like this: a method that finds out the relationship of ancient organisms found in the earth's crust of differentgeological layers, - paleontological.
Research results
A long study of the remains of long-extinct organisms shows that the lowest organized, that is, primitive forms of plants and animals are found in the most remote layers of rocks, the most ancient. And highly organized ones, on the contrary, are closer, in younger deposits. And not all fossils are equally significant for establishing their age, since the organic world has changed very unevenly. Some species of animals and plants existed for a very long time, while others died out almost immediately. If the remains of organisms are found in many layers and extend far along the vertical in the section, for example, from the Cambrian to the present, then these organisms should be called long-lived.
With the participation of long-lived fossils, even the paleontological method in biology will not help to establish the exact age of their existence. They are guiding, as already explained above, and therefore are found in very different and often very distant places from each other, that is, their geographical distribution is very wide. In addition, they are not a rare find, there are always a very large number of them. But it was the fossils, distributed in different rock strata, that made it easier to establish the sequence of changes in leading forms using the methods of general biology. The paleontological method is indispensable in the study of ancient organisms hidden by time under the thickness of sedimentary rocks.
A bit of history
Comparison of variouslayers of rocks and the study of the fossils they contain in order to determine their relative age - this is the paleontological method proposed in the eighteenth century by the English scientist W. Smith. He wrote the first scientific papers in this field of science that the layers of fossils are identical. They were successively deposited in layers on the ocean floor, and each layer contained the remains of dead organisms that existed just at the time of the formation of this layer. Therefore, each layer contains only its own fossils, from which it became possible to determine the time of formation of rocks in different areas.
The stages of the state of life in its development are compared by the paleontological method, and the duration of events is set very relatively, but their sequence, as well as the sequence of geological history at all its stages, can be traced reliably. Therefore, the knowledge of the history of the development of a certain section of the Earth's crust occurs through the establishment and restoration of the sequence of changes in geological events, the entire path can be traced from the most ancient rocks to the youngest. This is how the reasons for the changes that have led to the modern look of life on the planet are being clarified.
In geology
Paleontological methods in geology were first proposed much earlier. This was done by the Dane N. Steno in the middle of the seventeenth century. Moreover, he managed to quite correctly represent the process of formation of sediments of matter in water, and thereforehe drew two main conclusions. Firstly, each layer is necessarily bounded by parallel surfaces that were originally located horizontally, and secondly, each layer must have a very significant horizontal extent, and therefore occupy a very large area. This means that if we observe the occurrence of the layers at a slant, then we can be sure that the occurrence of this occurrence was the result of some subsequent processes. The scientist conducted geological surveys in Tuscany (Italy) and absolutely correctly determined the relative age of occurrences by the mutual position of the rocks.
English engineer W. Smith watched the canal being dug a century later and couldn't help but pay attention to the adjacent rock layers. All of them contained similar fossil remains of organic matter. But he described the layers that are far from each other as sharply different in composition. Smith's work interested the French geologists Brongniard and Cuvier, who used the proposed paleontological method and in 1807 completed a mineralogical description with a geographical map of the entire Paris Basin. On the map there was a designation of the distribution of strata with an indication of age. It is difficult to overestimate the significance of all these studies, they are priceless, since both the sciences and geology and biology began to develop exceptionally sharply on this basis.
Darwin's Theory
The founders of the paleontological method of determining the age of rocks by their division provided the basis for the emergence of a truly scientific justification, since, based on the discoveries of Brongniard, Cuvier, Smith and Steno,revolutionary new and truly scientific substantiation of this method. A theory about the origin of species appeared, which proved that the organic world is not separate scattered centers of life that arose and died out in some geological periods. Life on Earth has lined up according to this theory with extraordinary persuasiveness. She was not accidental in any of her manifestations. As if a great (and by the way, sung in many myths of ancient peoples) tree of life covers the earth with obsolete (dead) branches, and in the height it blooms and grows forever - this is how evolution was shown by Darwin.
Thanks to this theory, organic fossils have gained special interest as the ancestors and relatives of all modern organisms. These were no longer "shaped stones" or "curiosities of nature" with unusual shapes. They became the most important documents of history, showing exactly how organic life developed on Earth. And the paleontological method began to be applied as widely as possible. The entire globe of the earth is being studied: the rocks of different continents are compared in sections that are as far as possible from each other. And all these studies only confirm Darwin's theory.
Lifeforms
It is proved that the whole organic world, which appeared at the first, the earliest historical stages of the Earth's development, changed continuously. It was influenced by external conditions and situations, and therefore weak species died out, and strong ones adapted and improved. Development proceeded from the mostsimple, so-called lowly organized organisms to highly organized, more perfect ones. The evolutionary process is irreversible, and therefore all adapted organisms will never be able to return to their first state, the new signs that have appeared will not disappear anywhere. That is why we will never see the existence of organisms that have disappeared from the face of the earth. And only by the paleontological method can we study their remains in the rock masses.
However, far from all issues with determining the age of the layers have been resolved. The same fossils enclosed in different layers of rocks cannot always guarantee the same age of these layers. The fact is that many plants and animals had such an excellent ability to adapt to environmental conditions that many millions of years of their geological history lived without any significant changes, and therefore their remains can be found in almost any age deposits. But other organisms have evolved at a tremendous speed, and it is they who can tell scientists the age of the rock in which they were found.
The process of change in time of species of fauna cannot occur instantly. And new species do not appear simultaneously in different places, they settle at different rates, and they also do not die out at the same time. Relic species can be found today in the fauna of Australia. Kangaroos and many other marsupials, for example, on other continents, died out a long time ago. But the paleontological method of studying rocks still helps scientists get closer to the truth.
