Almost all sciences study the history of the development of our planet, and each has its own method. Paleontological, for example, refers to science, which studies the 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 functions 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.
The science
To better navigate in terminology, before acquaintance 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 paleontology restores, finds out, studies the conditions in which long-extinct plants and animals lived, explores how ecological relations between organisms developed, as well as the relations between existing organisms and an abiotic environment (the latter is called ecogenesis). The paleontological method for studying the planet's developmental paths concerns two sections of this science: paleobotany and paleozoology.
The latter studies the geological past of the Earth through the fauna that existed in those epochs and is divided, in turn, into the paleozoology of vertebrates and the 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 interactions of organisms of the distant geological past, their changes over the course of historical development under the pressure of circumstances. Taphonomy examines the fossil state of organisms in the laws of their burial after dying, as well as the conditions for their preservation. Paleobiography (or paleobiogeography) shows the distribution of various 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.
Stages
The conservation of fossil organisms in sedimentary rocks in this process contains three stages. The first is when organic residues accumulate as 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 by a sediment that limits the access of oxygen, but the process of destruction of organisms continues, since anaerobic bacteria still act.
It all depends on the rate of burial of the remains, sometimes sedimentation moves quickly, and burials change little. Such burials are called tafocenosis, 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 converting loose sediments into solid rocks, in which organic debris simultaneously turns into fossils. This happens under the influence 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 orictocenosis.
Determining the age of rocks
The paleontological method allows you to determine the age of the rocks by studying the fossils of the remains of marine animals that have been preserved in the process of petrification and mineralization. Of course, classification of the species of ancient organisms is indispensable. It exists, and with its help, prehistoric organisms found in the rock mass are studied. The study is carried out according to the following principles: the evolutionary development of the organic world is traced, the phased change in time of non-repeating complexes of dead organisms and the irreversibility of the evolution of the entire organic world. Everything that can be studied using paleontological methods applies only to bygone geological eras.
In determining patterns, it is necessary to be guided by the most important provisions that provide for the use of such methods. Firstly, in sedimentary formations in each complex there are only inherent fossil organisms, this is the most characteristic feature. Methods of paleontological studies allow us to determine the thickness of rocks of the same age, since they contain close or identical fossil organisms. This is the second characteristic feature. And the third is that the vertical section of sedimentary rocks is the same on absolutely all continents! It always follows the same sequence in the change of fossil organisms.
Governing minerals
Paleontological research methods include the guiding minerals method, which is also used to determine the geological age of rocks. The requirements for governing minerals are as follows: rapid evolution (up to thirty million years), vertical distribution is small, and horizontal - wide, frequent occurrence and good preservation. For example, it can be plate-branchial, belemnites, ammonites, brachionodes, corals, archaeocytes and the like. However, the vast majority of fossils are not strictly confined to a certain horizon, and therefore not in all sections they can be found. 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 managing complexes of forms.
Forms are completely different in meaning, and therefore for them, too, there is a division. These are the controlling (or characteristic) forms that either existed before the time being studied and disappear in it, or exist only within it, or the population flourished at that time, and disappearance occurred immediately after it. Colonial forms that appear at the end of the studied time are also distinguished, and by their appearance, a stratigraphic border can be established. The third forms are relict, that is, surviving, they are characteristic for the period of the previous one, then when the studied time 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.
Paleontological method in biology
In evolutionary biology, quite a wide variety of methods from related sciences are used. The richest experience has been gained in paleontology, morphology, genetics, biogeography, systematics, and other disciplines. It became the very basis by which it became possible to transform metaphysical ideas about the development of organisms into the most scientific fact. Particularly useful are the methods of general biology. The paleontological, for example, is included in all studies on evolution and is applicable to the study of almost all evolutionary processes. The greatest information is contained in the application of these methods on the state of the biosphere; all stages of the development of the world of organics can be traced up to our time by the sequence of changes in fauna and flora. The most important facts are also revealed fossil intermediate forms, restoration of phylogenetic series, detection of sequences in the appearance of fossil forms.
The paleontological method of studying biology is not one. There are two of them, and both relate to evolution. The phylogenetic method is based on the principle of establishing a relationship between organisms (for example, phylogenesis is the historical development of this form, which is tracked by the 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 the 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 obtained for biostratigraphy — species, genus, family, order, class, type, kingdom — in biology. The definition is as follows: a method that clarifies the kinship of ancient organisms found in the earth's crust of different geological layers is a paleontological one.
Research results
A long study of the remains of extinct organisms shows that the most low-organized, that is, primitive forms of plants and animals are in the most remote layers of rocks, the most ancient. A highly organized, on the contrary, is closer in younger sediments. 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 spread far vertically in a section, for example, from the Cambrian to this day, then these organisms must be called durable.
With the participation of long-lived fossils, even the paleontological method in biology will not help establish the exact age of their existence. They are guiding, as already explained above, and therefore are found in very different and often very remote places, 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 strata of the rock that facilitated the establishment of a sequence of changes in leading forms using 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
Comparing different layers of rocks and studying the fossils contained in them in order to determine their relative age is the paleontological method proposed in the eighteenth century by a scientist from England W. Smith. He wrote the first scientific papers in this field of science that the layers of fossils are identical. They sequentially deposited in layers on the ocean floor, and each layer contained the remains of dead organisms that existed just during the formation of this layer. Therefore, each layer contains only its own fossils, which made it possible to determine the time of formation of rocks in various places.
The paleontological method compares the stages of the state of life in its development, and the duration of the events is established relatively 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 whole path from the oldest to the youngest rocks can be traced. So the reasons for the changes that determined the modern look of life on the planet are found out.
In geology
Paleontological methods in geology were first proposed much earlier. The Danes N. Steno was still engaged in this in the middle of the seventeenth century. Moreover, he was able to correctly imagine the process of formation of sediments of matter in water, and therefore he made two main conclusions. Firstly, each layer is necessarily limited to parallel surfaces that were originally horizontally located, and secondly, each layer must have a considerable horizontal length, and therefore take up a very large area. This means that if we observe an oblique bedding, we can be sure that the occurrence of this bedrock was the result of some subsequent processes. The scientist carried out geological surveys in Tuscany (Italy) and absolutely correctly determined the relative age of occurrence according to the mutual position of the rocks.
An English engineer V. Smith, a century later, watched a canal being dug, and could not help but pay attention to adjacent layers of the rock. All of them contained similar fossils of organic matter. But he described the layers far from each other as sharply different in composition. Smith's works interested French geologists Broniard and Cuvier, they used the proposed paleontological method and in 1807 performed a mineralogical description with a geographical map of the entire Paris Basin. On the map was a designation of the distribution of strata with an indication of age. The importance of all these studies is difficult to overestimate; they are invaluable, since both science and geology and biology began to develop extremely sharply on this basis.
Darwin Theory
The founders of the paleontological method for determining the age of rocks by their dismemberment provided the basis for the emergence of a truly scientific justification, because based on the discoveries of Broniard, Cuvier, Smith and Steno, a revolutionary new and truly scientific justification for this method appeared. A theory appeared about the origin of species, which proved that the organic world is not a separate disparate foci of life that arose and died away at 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. It is as if a great (and by the way, glorified in many myths of ancient peoples) tree of life covers the obsolete (dead) branches of the earth, and blossoms above and blossoms forever - this is how evolution was shown in Darwin.
Thanks to this theory, the fossil remains of organics have gained particular interest as the ancestors and relatives of all modern organisms. These were no longer “curly stones” or “curiosities of nature” with unusual shapes. They became the most important documents of history, showing how the organic life on Earth developed. And the paleontological method began to be applied as widely as possible. The entire globe is being studied: 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.
Life forms
It is proved that the whole organic world, which appeared at the first, earliest historical stages of the Earth’s development, changed continuously. It was influenced by external conditions and situations, and therefore weak species became extinct, and strong ones adapted and improved. Development went from the simplest, the so-called low-organized organisms to highly organized, more advanced. The evolutionary process is irreversible, and therefore all adapted organisms will never be able to return to their first state, 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 investigate their remains in rock strata.
However, far from all issues with determining the age of formations have been resolved. The same fossils, enclosed in different layers of rocks, can not 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 for many millions of years of their geological history they lived without any significant changes, and therefore their remains can be found in almost any age deposits. But other organisms have evolved at great speed, and it is they who can tell scientists the age of the breed in which they were found.
The process of change in time of species of fauna cannot occur instantly.And new species do not appear at the same time in different places, settle at different speeds, and they do not die out at the same time either. Relict species can be found today in the fauna of Australia. Kangaroos and many other marsupials, for example, on other continents became extinct a long time ago. But the paleontological method of studying rocks nevertheless helps scientists to approach the truth.