The origin of life Life is the most wonderful and fascinating natural phenomenon. On the earth today, there are more than 6.5438+0.5 million kinds of animals, more than 400,000 kinds of plants and more than 200,000 kinds of microorganisms, forming a life world with butterflies flying, beautiful scenery and colorful flowers. From mountains to plains, from deserts to grasslands, from the air to rivers and lakes. There are traces of life everywhere. However, 4.6 billion years ago, when the earth was formed in the universe, it was not only hit by hundreds of millions of comets and meteorites, but also took about 6,543.8 billion years to lower the temperature by several thousand degrees Celsius. At that time, the earth was a lifeless and desolate world. After about 1 100 million years, it seems that simple cyanobacteria appeared on the earth. This is the origin of life on earth that people are generally concerned about. The origin of life is an important scientific topic in contemporary times, but it is also the most basic biological problem that is little known so far. In this article, we will introduce several theories about the origin of life. There have been various hypotheses about the origin of life in history, such as "God created" (that life was created by God or God) and "spontaneous generation" (that life, especially simple life, was naturally generated by inanimate matter. Most of these hypotheses are based on speculation and have been denied by people. Judging from the research papers published at the international conference on the origin of life held in recent years, contemporary hypotheses about the origin of life can be summarized into two categories: one is chemical evolution theory, and the other is cosmic embryo theory. The theory of chemical evolution holds that life originated from inorganic to organic under the condition of primitive earth. A series of chemical evolution processes from simple to complex. According to the theory of cosmic embryo species, the first life on earth came from the outer space of the earth, and it only developed on the earth later. According to the theory of chemical evolution, biological molecules such as nucleic acid and protein are the material basis of life, and the key to the origin of life lies in the origin of these biological substances, that is, on the lifeless primitive earth, due to natural reasons, abiotic substances react chemically, resulting in a variety of organic substances and biological molecules. Therefore, the origin of life is first of all the origin and early evolution of primitive organic matter. The function of chemical evolution is to create a class of chemical substances, which constitute common "structural units" such as amino acids and sugars, and life substances such as nucleic acids and protein come from the combination of these "structural units". 1938+0922, biochemist Obalin was the first to put forward a verifiable hypothesis. It is believed that some inorganic substances on the primitive earth became the first organic molecules under the action of lightning and the energy of the national emblem sun. 1953, after a lapse of 3 1 year, American chemist Miller first verified this hypothesis. He simulated the atmospheric composition on the primitive earth and synthesized organic amino acids by heating and spark discharge. Many experiments simulating primitive earth conditions have also synthesized other important biomolecules, such as purine, pyrimidine, ribose, deoxyribose, nucleoside, nucleotide, fatty acid, porphyrin and lipid. +0965 and 198 1 year. Insulin and yeast alanine transfer ribonucleic acid were synthesized for the first time in China. Protein and the formation of nucleic acid are the turning point from inanimate to living. The successful synthesis of the above two biomolecules has opened a new era of studying the origin of life by synthetic life. Generally speaking, the chemical evolution of life includes four stages: from small inorganic molecules to small organic molecules; Forming organic macromolecules from small organic molecules; From organic macromolecules, a multi-molecular system that can maintain its own stability and development; From a multi-molecular system to primitive life. In the past and now, many hypotheses belonging to the theory of cosmic embryo have been put forward. For example,1put forward at the 10th International Conference on the Origin of Life in July, 1993 that "the organic substances that cause chemical reactions and lead to life are brought by comets that collide with the earth"; Others infer that one of the comets that collided with the earth carried a "life embryo" across the universe and left it on the newborn earth, thus giving birth to life on the earth. A few years ago, a space physicist and an astrophysicist also explained the origin of life on earth as: the source of life on earth may come from one or several comets that fell into the ocean four billion years ago. They also believe that comets provide raw materials for the birth of life on earth (they call them "life-like creatures"). Although some scientists have strong opposition to this hypothesis (they think that "comets bring some substances, but they are not decisive, and the substances necessary for life already exist on the earth"), although this view is still a problem that needs further proof, through the study of meteorites and comets, the exploration and research of organic molecules on interstellar dust clouds and other planets, we can understand the formation and development laws of those organic molecules and compare them with those on the earth, which will be the origin of life on earth. The birth of primitive life with primitive metabolism and self-reproduction ability marks the end of the chemical evolution stage of the origin of life. The beginning of the biological evolution stage. The basis of life activities is a series of chemical changes, which are all completed under the catalysis of enzymes. The inheritance of life depends on the replication process of DNA. Primitive life is autocatalytic, and it needs a certain material basis to develop into stacking catalysis. It also needs a certain morphological structure. Cell is the basic structural unit and functional unit of life, which has complete functions, including enzyme catalysis and DNA replication. Primitive life is cell-free first, and then evolved into a cellular form, which is another qualitative leap. This process is the origin of cells in the origin of life. Cell origin is an important part of the origin of life. The significance of studying the origin of life is to clarify the history of the birth of life for billions of years. But its significance goes far beyond tracing the source, and lies in understanding life and environment, whole and part, structure and function, micro and macro, individual development and system development, and can further clarify genetic variation through the debate on the relationship between main matter and energy and information. The mechanism of life activities such as growth and differentiation, reproduction, metabolism, exercise induction and regulation, so as to understand and clarify the essence of life and realize the goal of human control and transformation of life. Although the study of the origin of life and cell is an attempt to reconstruct a distant historical process, unlike most other research fields, the complete origin process cannot be repeated in the laboratory. However, it can be phased. Step by step, simulate the test in the laboratory. Therefore, to study the origin problem, on the one hand, we need to find the answer in nature, on the other hand, it is more important to carry out simulation research at various stages of evolution in the laboratory, and to carry out research on synthetic life and synthetic cells. These studies not only help to clarify the origin of life and the origin of cells, in turn, their research results can guide people to artificially synthesize life materials, cells and even life according to needs, so as to realize life. The origin of life is an eternal mystery. When and where did life on earth come into being? How did it come into being? For thousands of years, people have encountered many traps and seen unprecedented light when solving this mystery. The first mystery of the origin of life is the time of its origin. The second question is the way in which life originated. How did life originate? Where did it originate? Since ancient times, there are many theories to explain the origin of life. Such as western creationism, China's Pangu creationism, etc. But it was not until the19th century that with the publication of Darwin's On the Origin of Species, great changes took place in biological science, and at the same time it brought a glimmer of light to reveal the eternal mystery of the origin of life, which is the modern chemical evolution theory. The chemical evolution theory of the origin of life was first proved by an American scholar Miller in 1953. What should the events about the origin of life described by Miller look like? That is, in the early days, the earth contained a large number of reducing primitive atmospheres, such as methane, ammonia, water, hydrogen and primitive oceans. When lightning struck the earth in the early days, these gases polymerized into various amino acids, which may be partially concentrated at normal temperature and pressure, and then further evolved into protein, other polysaccharides and polymer lipids, which may be pregnant and developed into life in a certain period of time, which is described by Miller. Life on earth may have been born 3.8 billion to 4 billion years ago, but we should be soberly aware that we still have a long scientific journey to solve the eternal mystery of the origin of life. The evolution from inorganic matter to organic matter, from organic compounds to organic life is also very accidental. It is not such an environment. Only with such conditions can life be produced. Someone once said that these inorganic substances are like a garbage dump, which contains everything, such as plastics, plastic bottles, iron, scrap metal and oil. Life, a single cell, is like a beautiful Mercedes-Benz. After a typhoon, these wastes were assembled into a Mercedes-Benz. Therefore, we can imagine the process of the origin of life is very, very difficult. Therefore, maybe we are the only paradise for life on this blue planet, so please protect our earth and cherish life on it. We can't expect the second origin of life on earth.