Chapter 1. Biology as a science about nature. Man is at the center of modern biology and medicine. Life and its properties. Levels of life organization
Biology (greek., bios — life, logos — word, study) — science about life as a special phenomenon in all its spatial-temporal manifestations. The term was coined in 1809 by G.B. Lamarck and G. Treviranus.
Biology of human. Object of study:
1) the life of man as a biological object is studied by anthropology — biological mechanisms of development and human life support;
2) a specific feature of human life is that a man is born with the ability to learn the program of cultural (social) inheritance, i.e., readily become public, a working, thinking being.
The life of humans as a biological object is studied by the complex of natural-scientific disciplines, or biomedicine, which combines the efforts of fundamental science and medicine representatives to solve specific tasks of practical health care.
Subject of research in biomedicine: biomedicine studies the life of biotechnology systems: genes, tissues, organs.
Methods of research in biology:
1) observation:
- by the naked eye or with the use of optical and other equipment (loupe, microscope, an electron microscope, the differential centrifugation, X-ray analysis);
- visualization of the living structures and processes (methods of radiology diagnostics — X-ray, ultrasound, CT scan);
2) experiment:
- in vivo — uses a living creature. (Feature — ethical problems);
- in vitro using living biological objects (cell, tissue, organ structure), grown outside the body. (Feature — problems of interpretation);
- natural «experiments» — mutations (the law of homologous series by N.I. Vavilov), and malformation;
3) modeling:
- mathematical;
- computer (design of medicines);
- biological (creation of living forms (cells, organisms) with set properties — knock-in, knock-out technology and others.
The basic properties that allow the existence of life:
- adaptation: individual, population, species, ecosystem, mechanisms and factors of evolution and co-evolution, adaptation;
- progress: biological, morpho-physiological, biotechnological (but biological regress);
- existence within the community.
In the process of development biology as a science, emerged a number of general ideas that characterize life:
- evolutionary doctrine (involvement of living forms in the process of historical development of the earth);
- cell theory (cell — elementary unit of life);
- the principle of ecosystems (life — there is always the community of organisms of different species);
- self-regulation of living systems;
- theory of ontogenesis (genetic bioinformation implemented in phenotype in the process of ontogenesis).
Cell theory. It has been proven that the cell is the basic unit of all living things, because it has all the properties of living organisms: structure, receiving energy from the outside and its use for work and consistency, metabolism, an active response to irritation, growth, development, reproduction, duplication and transfer of biological information to descendants, regeneration and adaptation to environment.
The main provisions of the cellular theory:
a) the cell is the elementary structural and functional unit of the living; there is no life outside the cell;
b) cell is an integrated system, which includes many interconnected elements — organelles, representing an integral functional unit;
c) all the cells are homologous by their structure, chemical composition and the basic properties;
d) new cells are formed by dividing the original cell after doubling its genetic material (DNA): the cell from the cell;
e) a multicellular organism is a new system composed of many cells integrated into the tissues and organs, connected with each other by chemical factors of humoral and nervous regulation;
f) cells of multicellular organisms have the genetic potential of the organism, the equivalent genetic information, but they differ in gene activity, leading to their varying differentiation.
The basic properties of the living:
a) unity of chemical composition (98% carbon, oxygen, nitrogen, and hydrogen);
b) metabolism is the process of synthesizing and breaking down substances in the body;
c) similar structure: all living organisms have a cell structure. Outside the cell there is no life;
d) reproduction is the body’s ability to reproduce their own kind. This ensures the preservation of the species;