For the knowledge of the functioning of organisms of animals and humans, of great importance were experiments by I.P. Pavlovin the field of physiology of higher nervous activity. The scientist studied the process of interaction between living organisms and the external environment, the reaction to the influence of which is carried out through conditioned and unconditioned reflexes.
In the 1920-1930s. studies were carried out that allowed highlight of human body pure enzymes and vitamins, and then reproduce them chemically. Thanks to this, it is possible to save people from a number of diseases. Fundamentally new drugs were received - antibiotics, which have the property of destroying microorganisms dangerous to humans. During the Second World War, antibiotics (especially isolated from mold penicillin) and synthesized chemical drugs with similar properties ( streptocide and inorganic sulphides) saved the lives of hundreds of thousands of people. Developed rapidly vaccination from various diseases: measles, poliomyelitis, leprosy, etc.
At the beginning of the XX century. in the USA there was scientific school genetic biologists, led by T. H. Morgan... She owes merit creation of the chromosomal theory of heredity... It was proved that the transmission of hereditary traits and changes in hereditary properties (mutation) occur at the gene-chromosomal level. The Russian scientist N.K.Koltsov was the first to put forward the later confirmed hypothesis of the molecular structure of chromosomes... These discoveries formed the basis for scientifically grounded breeding of new varieties of plants and animal species. Geneticist N. I. Vavilov was one of the creators of the modern teaching about biological basis of selection... He organized expeditions to different countries and collected the world's largest collection of seeds of cultivated plants. Material from the site
In the 1940s. scientists have determined that the genes contain deoxyribonu-kleinic acid (DNA), which is an informative carrier of hereditary traits. In the 1950s. Englishman F. Creek and American J. Watson completed dNA model creation, and soon it was possible to obtain X-rays of the DNA molecule and establish it structure... In the 1970s. began to develop genetic Engineering - purposeful design of new combinations of genes that do not exist in nature. At the end of the XX century. English scientists cloned sheep (named Dolly). In 2000, American researchers found the genetic structure of cholera vibrio; in laboratories in the USA and England deciphered the human genetic code.
Over the century, it has developed intensively psychology... At the origin psychoanalysis theories, which became widespread, was the Austrian scientist Z. Freud... According to his views, unconscious motivations that arise on the basis of accumulating experiences and unfulfilled desires are of decisive importance in people's behavior. The theory of psychoanalysis is used both in cultural studies and social psychology, and in practical medicine (treatment with psychoanalysis). If Freud and his followers focused on the unconscious, then the Russian scientist L. S. Vygotsky focused on the study of consciousness... He founded a major scientific school in psychology.
Strictly speaking, DNA was discovered back in the 19th century by Friedrich Miescher. However, at that time, the young Swiss scientist did not understand the value of his discovery, the fact that the structure he discovered carries complete information about living objects. We figured out the details later. In 1953, English scientists Watson and Crick managed to understand the structure of the DNA molecule and understand that it contains encrypted information that can be inherited. Rosalyn Franklin, whose work and photographs of DNA helped Watson and Crick complete their work, also contributed a lot to the discovery. The discovery of DNA has had a huge impact on the natural sciences. The study of viruses and bacteria, the breeding of crops from which a greater yield can be obtained, the receipt of medicines, the treatment of many diseases, an understanding of a number of evolutionary processes - after the decoding of DNA, new horizons opened up for scientists.
Watson organized the Human Genome Project, which deals with the sequencing of nucleotides in the human genome. Watson also became the first person whose DNA was decoded.
Immortality
Eternal life has long occupied the minds of people, but it was not until the 20th century that the first steps were taken in biology to study what death is, and whether there are ways to delay or even prevent this event. Sydney Brenner was the first to suggest that cells are genetically programmed to die. In the course of his work, he also isolated the first gene that triggers the destruction cell structure... Later, another scientist, Robert Horwitz, was able to find two more genes that lead to cell suicide, as well as a gene that prevents this. In the 21st century, work in this direction continues. Scientists hope that further deciphering of the genome will finally shed light on the mechanisms of aging and death and will help control these processes.
In 2002, Sydney Brenner received the Nobel Prize for his discoveries.
Stem cells
Although the term "stem cell" itself was born at the beginning of the 20th century, scientists paid close attention to them only in the nineties. Stem cells possess important property - they are able to transform into any other type of cells. With transplantation, the main problem is finding a compatible organ that can still be rejected by the body after transplantation. Using stem cells will solve this problem, because a new heart or kidney can be grown from the patient's cells. Such an organ will take root perfectly.
The end of the XX century and the beginning of the XXI, entailed a string of discoveries. New discoveries in biology raise a bunch of questions in front of them that make scientists think that everything is not so simple in this world. The search for truth is the main goal of researchers.
Discoveries in XX century biology
In 1951, researcher Erwin Chargaffu came to one conclusion, which radically changed the view of the structure of nucleic acids. It was previously believed that all nucleic acids are created from tetra-blocks, therefore they lack specificity. For three years, the scientist was engaged in research and, finally, was able to prove that nucleic acids obtained from different sources differ in their composition from each other - they are specific. The scientist built a model of DNA that looked like a double helix, when placed on a plane, it looked like a ladder. It was found that the structure of one single DNA branch determines the structure of its other branch - this is due to the fact that the base of the adjacent ones determines the sequence of other guides. Thus, a new property of DNA was defined - complementarity.
Further, research was needed in the field of molecular biology that would decipher the mechanism of DNA replication and transcription. Scientists suggested that the thread unwinds, its threads diverge, and then, in accordance with the rule of complementarity, a molecule is formed from each thread. A little later, experiments confirmed this hypothesis.
In 1954, Georgy Antonovich Gamow, based on the research of Erwin Chargaff, suggested that amino acids are encoded from a combination of three nucleotides.
In 1961, French scientists Jacques Monod and François Jacob recreated the circuitry that regulates active genes. Scientists said that DNA has not only informational genes, but also genes-operators and genes-regulators.
New discoveries in biology of the XXI century
In 2007, a team of scientists from the University of Wisconsis-Madison and the University of Kyoto conducted one experiment, in which adult skin cells began to behave like embryonic stem cells. The cell was able to transform into almost any species. The financial framework can be discarded, because in this way, cells from human DNA can become an organ for transplantation. The organ grown in this way will not be rejected by the patient's body.
The Human Genome study was completed in 2006. This project was named the most important research in the field of biology. The main goal of the work is to determine the sequence of nucleotides, as well as to study about 20,000 thousand human genes. Under the guidance of scientist James Watson, in 2000. part of the genome structure was presented, and in 2003. the study of the structure has been completed. Despite the fact that the "Human Genome" was officially completed in 2006, the analysis of some areas continues today. This research opens up new theories of evolution. The knowledge gained during the work is already actively used in medicine.
In the XX century, biology as a science made great strides forward, and the beginning of the XXI century is already remarkable for discoveries. It can be assumed that new discoveries in biology will reveal many secrets and mysteries that, perhaps, can turn over all past knowledge and approved theories.
Ten significant discoveries of the first decade of the 21st century - video