What could paleontology be based on?

I. Definition of Paleontological Fossils

The remains of ancient animals or plants preserved in crustal rocks or evidence indicating the existence of remains are called fossils. Simply put, a fossil is a stone made from the remains or remains of creatures living in the distant past.

Second, the types of paleontological fossils

Fossils can generally be divided into three categories: corpse fossils, trace fossils and chemical fossils; According to biological fossils, it can be divided into animal fossils, plant fossils and microfossils. According to the preservation characteristics, it can be divided into solid fossils, die-casting fossils, trace fossils and chemical fossils.

Third, the basic conditions for the formation of paleontological fossils

1, organic matter must have hard parts, such as shells, bones, teeth or woody tissues. However, even very fragile organisms, such as insects or jellyfish, can become fossils under very favorable conditions.

Living things must avoid being destroyed immediately after death. If an organism's body is partially crushed, decayed or severely weathered, it may change or cancel the possibility of this organism becoming a fossil.

3. living things must be buried quickly by things that can hinder decomposition. The type of this buried material usually depends on the living environment of organisms. The remains of marine animals can usually become fossils, because marine animals sink to the bottom of the sea after death and are covered with mud. In later geological periods, mud became shale or limestone. Fine-grained sediments are not easy to destroy biological remains. In some fine-grained sedimentary rocks of Jurassic in Germany, some fragile organisms such as birds, insects and jellyfish are well preserved.

Although many unknown creatures have appeared on the earth, only a few have left fossils. Even if all the conditions for organisms to become fossils are met, there are other reasons why they cannot become fossils. For example, many fossils are destroyed by ground erosion, or its hard parts are decomposed by groundwater. Some fossils may be preserved in rocks, but because rocks have undergone strong physical changes, such as folding, breaking or melting, this change can turn marine limestone containing fossils into marble, and any biological traces that originally existed in limestone will disappear completely or almost completely.

Formation process of paleontological fossils

1. Organisms will be buried quickly after death to avoid being swallowed by scavengers and destroyed by natural forces.

2. The skin and muscles of living things slowly decay, leaving only bones that are not rotted.

3. In the process of cementing into rocks, bones themselves are also replaced by minerals and eventually become fossils.

4. After the later crustal movement, the rock strata containing biological fossils were weathered and denuded, and the fossils were exposed to the surface.

In short, it is difficult to obtain fossils, especially vertebrate fossils. We know that fossils are formed by fossilization of biological organisms. For example, vertebrates, after death, their bodies will be eaten or decomposed by other animals, and their bones will be separated and decomposed. In most cases, it just disappears slowly on the surface, leaving no trace. However, in rare cases, animals are buried in sediments shortly after death and cannot be preserved for a long time without separation and decomposition. The fossilization process of fossils is quite complicated, including many chemical and physical processes. Maybe no one can imagine the probability of fossil formation: maybe less than one in a million. Animal fossils, especially well-preserved fossils, are very rare.

Types and division methods of paleontological fossils

According to its preservation characteristics, it can be roughly divided into four categories: solid fossils, die-casting fossils, trace fossils and chemical fossils.

1, solid fossil

Refers to fossils that are almost completely or partially preserved by paleontological remains themselves. Protozoa can avoid air oxidation and bacterial corrosion under particularly suitable conditions, and their hardware and software can be completely preserved without major changes. For example, the mammoth (found in the frozen soil of Siberia during the Quaternary Glaciation 190 1 year ago, not only the bones are intact, but also the skin, hair, flesh and blood and even the food in the stomach are well preserved).

2. Molded fossils

It is the imprint or recasting left by biological remains in strata or surrounding rocks. The first is the imprint, that is, the imprint left by the biological debris falling to the bottom of the water. The remains are often destroyed, but this imprint reflects the main characteristics of organisms. The second category is impression fossils, including external model and internal model. The external model is the trace of the hard part of the relic (such as shell) printed on the surrounding rock, which can reflect the original biological appearance and structure; Internal model refers to the traces of the internal contour structure of shells printed on surrounding rocks, which can reflect the internal morphology and structural characteristics of biological hardware. The third type is called core, and the sediment filler in the shell mentioned above is called core. Its surface is an internal model. The shape and size of the core is equal to the size of the internal space of the shell, and it is an entity that reflects the internal structure of the shell. The fourth is casting mold. When the shell is buried in the sediment and the outer mold and the inner core have been formed, the shell is completely dissolved and filled with another mineral, so that the filling keeps the original shape and size of the shell, just like the casting process, thus forming the casting mold.

3. Trace fossils

Refers to the traces and remains of ancient life activities preserved in rock formations. The most important trace fossils are footprints. In addition, there are traces of crawling, caves, drilling holes of arthropods and hidden caves formed by tongue-shaped shellfish living in coastal areas, which can form trace fossils.

4. Chemical fossils

Although the remains of some ancient creatures have been destroyed and not preserved, amino acids, fatty acids and other organic substances formed by the decomposition of organic components that make up the creatures can still remain in the rock strata. This kind of fossil is invisible, but it has a certain chemical molecular structure, which is enough to prove the existence of past organisms. This kind of fossil is called chemical fossil.

Identification methods and common tools of fossils

Determine the classification order and name of fossils. Fossils are the research objects of paleontology. Fossils are mostly the remains, remains or relics of ancient creatures, such as hard tissues, local body marks, certain organs, excreta, etc., which are the products of fossilization. Generally, only its morphological characteristics are preserved. Therefore, the identification of paleontological fossils is mainly based on morphology. In some categories, the higher classification order is classified according to the natural system, while the lower classification order cannot be classified according to the natural system, so it is necessary to identify the species, genera and even families of certain forms or organs, such as conodonts, plant spores and pollen, footprints and so on.

The specific identification methods of various paleontological fossils are different, but they generally go through the following steps: ① Familiar with the external morphology and internal structure of specimens, and generally observe the fine structure or microfossils of large fossils with the help of solid mirrors, microscopes or electron microscopes. Sometimes it is necessary to slice fossils continuously to understand their internal structural characteristics; (2) Make use of the knowledge learned, consult relevant literature, determine a larger classification order, and generally assign it to families; (3) Further searching the genus and species of the specimen by using documents such as search tables and search boards; ④ Select representative group specimens or typical single specimens for feature description, measure various character elements and take photos.

When identifying fossil specimens, we mainly rely on the relevant monographs of fossils found in a certain category or stratum, and consult the relevant papers published after the publication of the monographs. After correct and comprehensive data consultation and comparison, the appraisers found that the fossil to be identified was completely consistent with a biological fossil recorded in the literature, and the fossil could be classified as the same name. If you can't find the same description, you can establish a new classification of species and genera according to these specimens and give appropriate names. Specimens that establish new species are called type specimens, and a species of a genus is named type species. Similarly, there are type genera and so on.

Because species live in groups, there are continuous individual differences. However, the type specimen is often only the first discovery of a species, which may not fully reflect the characteristics of the species. Under the guidance of this concept, no individual is a "typical" group character. When identifying species, we should collect specimens as comprehensively as possible, so that these specimens can generally reflect the general appearance of the real population. Then, various statistical methods are used to distinguish interspecific variation from intrapopulation variation, so as to achieve the purpose of identifying species.

After the specimen identification, it should be recorded. A complete description of a paleontological species includes the following items in turn: scientific name, plate, list of similarities and differences, number and preservation place of type (population) specimens, identification points, description, measurement and other data discussion, origin and horizon.

Significance of studying paleontological fossils

Fossil research involves two different disciplines, namely geology and biology. In geology, the study of fossils is an indispensable part of historical geology, paleontology and paleogeography (historical tectonics and dating history). Through the study of fossils, we can understand the paleoclimate, paleogeography and paleoecological environment, and also locate the stratigraphic sequence in time. In biology, paleontology is an important branch of group biology, in which fossil research is the only object. The research (including the traditional classification description of paleontological fossils and the electron microscopic study of modern nannofossils) is of great significance to the origin of life, the evolution of organisms, the influence of environment on organisms and the classification system of organisms.

The paleoecological study of biological fossils is an important basis for reconstructing geological history, paleogeography and paleoclimate. Every living thing is the result of living in a certain environment and adapting to it. The habits, behaviors and body shapes of all kinds of creatures have the characteristics of reflecting environmental conditions. Using these characteristics, we can infer the living environment of organisms, such as marine fossils, corals, foraminifera and so on. The leaves, roots and insects of terrestrial plants reflect the continental environment. According to the study of the living environment and climatic conditions of various biological fossils in a geological period, we can infer the land and sea distribution, coastline position and the scope of lakes, rivers and swamps in that period. The reconstruction of paleoenvironment and paleoclimate is very important for understanding geological history. In addition, the hard parts of organisms can also form rock marks reflecting the paleoenvironment and paleoclimate, such as shell rocks reflecting the coastal environment, reefs reflecting the warm sea environment at low latitudes, peat or coal reflecting the wet swamp environment, and so on.

The collection of a large number of fossil data also provides a basis for the systematic classification of paleontology. Modern organisms developed from ancient organisms through a long geological period, and there are different degrees of kinship among various organisms, thus establishing a natural classification system that reflects the kinship and evolution of the biological world.

The value of paleontological fossils

1, huge economic value

As we all know, Jurassic Park made a fortune by expressing paleontology and its living environment in the most modern way. Coincidentally, the first issue of Fossil magazine, a well-known publication of the Chinese Academy of Sciences, said in 2000: "When a fossil named' Little Liaoxi Bird' collected by Hao Xiurong was exhibited by the Chinese Academy of Sciences abroad, someone once wanted to invest 200 million US dollars to collect it." According to Professor Dong Zhiming of Chinese Academy of Sciences, it is internationally stipulated that smuggled goods cannot be studied and purchased. If a bird fossil can be smuggled abroad, it can be sold for 1000 dollars, and it can be sold for 50,000 dollars with the approval of the customs. This is a conservative estimate. 1998 A reporter who published an article in Fossil magazine estimated that the value of Confucius bird had risen to the point of "a bird building". There is also an economic value. At the end of May and the beginning of June, 2000, Chinese and foreign scientists attending the 5th World Congress of Ancient Birds went to Chaoyang to see the strata, and their accommodation and meals were paid for by themselves. Chaoyang people received the first large amount of foreign exchange attracted by paleontological fossils. Some people put forward the concept of "fossil economy", thinking that fossils have entered the market and the situation is bound to move towards the market. Today, with the development of history, fossils have a new function, that is, they are bought and sold as a kind of strange stone. So the era of fossil economy is inevitable. (See "Fossil" magazine, No.2, 2000) At present, the number of people engaged in the fossil industry in Chaoyang City has not been counted, and many people have made a fortune from fossils (excluding those who smuggled fossils). As long as you go out, you will not only spread the culture, but also earn money and do business abroad.

2. Great scientific value

Paleontological fossils are an important basis for identifying and comparing strata and understanding the history of the earth. They are precious materials for studying the origin, development history and laws of animals and human beings, and are also physical materials for the masses to learn and understand the history and laws of nature and human beings and establish a materialistic world outlook. Rich and colorful fossils prove that all kinds of life on earth were not created by any god, but formed after long-term evolution after the emergence of single-celled life. Not only that, it can also show us a prehistoric biological history, give people knowledge and appreciate the beautiful scenery of nature. Xu Guanhua, Vice Minister of Science and Technology, said: The Jehol biota in western Liaoning (Chaoyang) has both geographical advantages and scientific and technological advantages, and it is a promising field. Paleontological fossils are physical evidence to study the living habits, reproduction methods and ecological environment of animals and plants at that time. It is the verification of paleogeography, paleoclimate, earth evolution and biological evolution. It can provide a rare entity and field for studying the mass death and extinction of life on earth.

3. Scarce tourism resources

Fossils are intellectual, cultural, ornamental and interesting, and the origin of fossils is different, so fossils and fossil origin are tourism resources. Fossils and fossil producing areas can form scenic spots independently, or they can be part of other scenic spots. China Tourism Encyclopedia and China Scenic Area Dictionary list 94 fossil tourist attractions, some of which are places of origin, some are sites, some are museums, some are nature reserves, and Chaoyang will be the 95th one. Most people have a strong desire for knowledge and a demand for exploring mysteries, and fossil sites can meet this requirement to varying degrees.

Some wishes and requirements, so fossils and fossil producing areas are attractive to tourists.

Of the more than 1000 dinosaur eggs lost overseas in China, only three are priceless embryo fossils, each worth $250,000 in the United States. Germany has offered a reward of 5 million marks to each find its national treasure archaeopteryx fossils.

Experts pointed out that paleontological fossils have more important scientific value than economic value.

Paleontological fossils also have important aesthetic appreciation value. Some special fossils with special shapes have high aesthetic appreciation value and collection value by themselves or after processing. Therefore, in a certain sense, they are also an important tourism resource and tourism commodity resource.

In addition, some paleontological fossils have important medicinal value. Paleontological fossils preserved in a specific geological environment, such as some special vertebrate fossils and their mixtures, have important medical value.

The process of human understanding of fossils

The English name of fossil is "fos-sil", which comes from the Latin word "fossil". It is changed from the verb "fodere" and has the meaning of digging out. As early as ancient times, Hippolytus, Greece, quoted the works of Sanofini, and thought that the remains of marine animals found on mountains far from the coast were left by animals trapped in mud at that time and later solidified. At the same time, there are also records about the keel in Shan Hai Jing written by China in the late Spring and Autumn Period or the early Warring States Period (about the 5th century BC). In the following period, the keel was regarded as a dragon slough similar to a snake slough, and bone fossils were associated with legendary creatures. By 1 1 century, Su Song in the Song Dynasty clearly pointed out in his "Illustration of Materia Medica" that the keel was not the slough of a dragon, but the hard parts such as bones, horns and teeth of a dead dragon.

During this period, the records of silicified wood and other fossils in China's works have become very common. It is obvious from these accounts that some scholars in China compared these fossils with modern creatures and tried to infer the ancient climate. But they are not very clear about the formation of fossils. The understanding of fossils in this period should be represented by Shen Kuo. Meng Qian's Bi Tan (Volume 2 1)No. 17 records: "Bamboo shoots under Yanzhou soil ... have turned into stones. ..... Yan Wudu, this ... I don't know which generation it is. Nothing more than before the beginning of the world, the land was simple and humid, suitable for bamboo evil. Jin Huashan, Wuzhou ... Walnut, reed root, fish and crab have all succeeded ... "Another example is the volume 1 1, which says," Going north to Taihang Mountain, between cliffs, people often hold snail shells like birds' eggs, and cross stone walls like belts. This is the seaside in the past, and it is nearly a thousand miles away from the sea today. " Shen Kuo's records are closely related to fossils. From the point of view of modern paleontology, we can see that: firstly, the snail shells between the cliffs of Taihang Mountain are brachiopod or mollusk fossils in Paleozoic strata. Secondly, Jinhua, Wuzhou, Zhejiang Province, which is now the central and western part of Zhejiang Province, found a variety of plants and fish and shrimp fossils in Mesozoic strata. As for the third point, according to the research of paleontologists in China, it may be an extinct pteridophyte fossil ── new phosphorite. Similar records can often be seen in other books of this period, such as Yan Zhenqing's "Magu Xiantan Ji", which records that "there are still snails in the high rocks, or that the mulberry field has changed". Zhu said: "I have seen snails and mussels in the mountains, or in the original stone." This stone is old-fashioned, and snails are things in the water. " For example, from the Han and Jin Dynasties to the Tang and Song Dynasties, fish fossils in Xiangxiang, Hunan Province were recorded many times. At the same time, keel, dragon teeth, rock swallow, stone crab, stone snake (possibly gastropod fossils) and so on have also been used as medicine. Bat stones, right-angled stones and fish fossils have all been used as decorations.

In Europe, Leonardo da Vinci first proposed in 1508 that fossils are the remains of animals and plants that once lived. Some scientists also use "fossils" to refer to stones, minerals, utensils and other collectibles, including real fossils. For example, the German doctor G. Bauer focused on why these fossils are stony and whether they have medicinal value. C. Gesner, a Swiss doctor and naturalist, compared fossils with modern creatures, but was limited by the level of biological knowledge at that time. In addition, Italian doctor, geologist G. Fracastoro and French writer and ceramist B. Palisi all found fossils of bivalves, gastropods and fish bones.

Danish geologist and anatomist N Stena wrote an unpublished article on "Tongue Stone" (shark tooth fossil) in 1667 based on his detailed observation of many geological phenomena. Stena proposed that fossils are the remains of ancient creatures, and careful study of fossils may explain the ages of various geological events. A famous episode about fossils also happened in this period. As an avid religious natural scientist, J.J. Scheuch regarded the salamander fossils in the Miocene lacustrine sedimentary lignite bed in Aingen, Switzerland in 1726 as the remains of sinners during the Great Flood in the Bible, and named them Homo diluvii testis (flood witness). This error was not corrected by Ye Wei until 18 1 1. He pointed out in the fifteenth paper of the fourth volume of the four-volume masterpiece published by 18 12 that this fossil is not a "human" but a Proteus. It was not until 1837 that another scholar officially named it Shuo's salamander.

In Europe, since W. Smith, C. Lyle and especially C. R. Darwin, the understanding of fossils has gradually deepened, reaching the research level of paleontology as a modern science.

In China, due to the long-term feudal small-scale peasant economy and the imperial examination system, the seeds of ancient science and technology gradually disappeared. /kloc-After the middle of the 0/9th century, the re-understanding of fossils was introduced into China from Western Europe or China from Western Europe via Japan as a part of modern science.