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What are the research methods in biology? Research methods. II. Learning new material

Biology is the science of life in its most diverse manifestations. The functioning of single-celled organisms, the behavior of males and females during the mating season, patterns of inheritance of traits - this and much more are within the scope of interests of science. The subject of studying biology is all these manifestations of life. Its methods are aimed at searching for patterns of structure, functioning of organisms, and their interaction with the environment. In essence, they study those properties that distinguish living matter from nonliving matter.

Divisions

Biology is a combination of several sciences, the focus of which is on different objects:

• zoology;
• botany;
• microbiology;
• virology.

Each of them, in turn, can be divided into several smaller ones. For example, in zoology, ichthyology (studies fish), ornithology (studies birds), algology (studies algae), and so on coexist.

Classification option

Another principle of dividing biology into components is properties and according to it they distinguish:

• molecular biology;
• biochemistry;
• cytology;
• genetics;
• developmental biology;
• anatomy and physiology of various organisms;
• ecology (often today considered as a separate science);
• embryology;
• theory of evolution.

Thus, the subject of studying biology remains unchanged - it is life itself. Its various manifestations are studied by separate disciplines. There is also general biology. Its focus is on what distinguishes it from inanimate life, as well as its ordered hierarchical structure and the relationship of individual systems between themselves and the environment.

Experience and theory

The methods of studying biology are generally similar to the ways of knowing in other scientific disciplines. They are divided into empirical (practical, experimental) and theoretical. Practical methods for studying biology reveal various parameters, properties and features of living systems. Theories are then developed based on them. This process is cyclical, since the study of biology is most often used on the basis of existing conclusions. Theories, in turn, always require additional experimental verification.

Primary collection of information

One of the main empirical methods is observation. It is a study of the external signs of an object and its changes in the conditions of its natural habitat over some time.

Any study of a living system begins with observation of it. The history of the study of biology perfectly illustrates this point. In the early stages of the development of science, researchers could only use this empirical method. Today the observation has not lost its relevance. It, like other methods of studying biology, uses numerous technologies. For observation, binoculars, various cameras (night vision, deep-sea, etc.), various laboratory equipment, such as a microscope, and others are used.

Based on whether equipment is used in the process, observation can be divided into two types:

• Direct. It aims to study the behavior and characteristics of various organisms.
• Instrumental. Using various equipment, the characteristics of tissues, organs, cells, chemical composition and metabolism are studied.

Experiment

As is known, not all phenomena and processes associated with living systems can be observed directly in their natural environment. In addition, understanding some patterns requires certain conditions that are more convenient to create artificially than to wait for them to appear in nature. A similar approach in biology is called the experimental method. It involves studying an object under extreme conditions. Studying the body when it is exposed to high or low temperatures, high pressure or excessive stress, when placed in an unusual environment, helps to identify the limits of its endurance, discover hidden properties and capabilities. As technology improves, the potential of experimental methods increases. The data obtained in this way is becoming more and more accurate. The conditions created during the experiment can be varied almost indefinitely.

One of the main uses of an experiment is to test previously stated hypotheses. Data obtained from experience make it possible to correct the theory under consideration, confirm it, or lay the basis for a new one. Experimental methods for studying biology, examples of which can be found in large numbers on the pages of textbooks, contribute to a deeper penetration of scientists into the secrets of living matter. It is thanks to them that modern science has achieved such progress.

Comparison

The historical method allows us to identify evolutionary transformations of communities and species. It is also called comparative. The chemical and anatomical structure, features of functioning, and hereditary material of organisms at different levels are analyzed. Not only living organisms are used as objects, but also already extinct ones.

This technique became the main source of data for Charles Darwin during the period of his formulation of the theory of evolution.

What I see, I write down

The descriptive method is closely related to observation. It consists in recording the noticed properties, signs and features of objects with their subsequent analysis. The description method is considered the most ancient in biology: initially, at the dawn of science, it was with its help that various patterns in nature were discovered. The recorded data is carefully analyzed, divided into important and unimportant within the framework of a particular theory. The described features can be compared, combined, classified. Only on the basis of this method were new classes and species discovered in biology.

Without mathematics you can't go anywhere

All information collected on the basis of the described methods requires further transformation. Biology actively uses mathematical apparatus for this. The obtained data is translated into numbers, on the basis of which certain statistics are built. In biology, it is impossible to unambiguously predict this or that phenomenon. That is why, after analyzing the information, a statistical pattern is revealed. Based on these data, a mathematical model is built that makes it possible to predict some changes within the living system being studied.

Such processing allows you to structure the information received. Based on the created models, it is possible to predict the state of the system after almost any period of time. Thanks to the use of a fairly impressive mathematical apparatus, biology is increasingly turning into

Synthesis

Along with the penetration of cybernetics ideas into biology (they underlie modeling), both of these trends are beginning to be actively used in biology. Both of these trends influence the methods of studying biology. The structure of living structures is presented in the form of a hierarchy of systems at different levels. Each higher level is elements interconnected based on certain patterns, which are also systems, but at a lower level.

This approach is typical for a large number of disciplines. Its penetration into biology indicates a transition in science as a whole from analysis to synthesis. The period of in-depth study of the internal structures of individual elements gives way to a time of integration. The synthesis of all data obtained in biology, and often in related sciences, will lead to a new understanding of the interconnections of natural systems. An example of concepts built on the basis of integration are the theory of neurohumoral regulation, the synthetic theory of evolution, modern immunology and systematics. The appearance of each of them was preceded by the accumulation of a large amount of information about individual structural units, features and characteristics. At the next stage, the collected data made it possible to identify patterns and create generalizing concepts.

Trend

Synthetic methods for studying biology indicate a transition from the theoretical. The initial accumulation of facts and data allows us to put forward certain hypotheses. Then, in most cases, they are tested using experimental methods. Confirmed hypotheses are translated into patterns and form the basis of theories. Concepts formulated in this way are not absolute. There is always a chance that new information will require reconsidering established views.

All types of studying biology are aimed at understanding the properties and characteristics of life. However, it is impossible to single out any one method as the main one. The current level of knowledge has been achieved only through the simultaneous use of all these methods of understanding the world around us. In addition, biology does not distinguish methods of studying humans from methods of collecting and analyzing data about any other organism. This shows their versatility. For each level of the hierarchical organization of living systems, the same study methods are used, but in different combinations. The transition to the use of cybernetic and systems techniques indicates integration not only within biology, but throughout science as a whole. The synthesis of knowledge from different disciplines contributes to a deeper understanding of the basic patterns of the world in which we live.

• Biology - the science of life, its forms and patterns of development.
• Method- this is the path of research that a scientist goes through.
• Scientific method is a set of techniques and operations used in constructing a system of scientific knowledge.

Biological methods are divided into:

1. Empirical- allows you to study a phenomenon through experience.
   • descriptive,
   • comparative,
   • experimental,
   • historical.
2. Theoretical
   • statistical,
   • modeling.

The main (universal) methods in biology include:

1. Descriptive method associated with the observation and description of objects or phenomena, the determination of their properties.
2. Comparative method. The similarities and differences between different systematic groups, communities of organisms, their structure, functions and components are studied using comparative method. This method is used in taxonomy, morphology, anatomy, paleontology, embryology and other branches of science. The principles of comparison formed the basis of systematics and cell theory. The biogenetic law and the law of homological series in hereditary variability were discovered.
3. Historical method clarifies the patterns of the appearance and development of organisms, the formation of their structure and functions during the geological history of the Earth. With his help, the doctrine of the evolutionary development of the organic world was created.
4. Experimental method(experience, practice) consists in the researcher changing the conditions of existence of the object of experience, its structure and observing the results of the changes. Experiments can be field or laboratory. This method allows us to study much more deeply the essence of behavior, structure and characteristics of organisms.

Particular biological research methods include methods

1. Genealogical method. It is used in compiling pedigrees of people and identifying the nature of inheritance of certain traits.
2. Historical method. Allows you to discover patterns of origin and development of living beings.
3. Paleontological method- allows you to find out the relationship between ancient organisms that are located in the earth’s crust in different geological layers.
4. Centrifugation- separation of mixtures into main parts under the influence of centrifugal force.
5. Cytological, cytogenetic, microscopy- study of the structure of the cell, its structures using microscopes.
6. Biochemical method- study of chemical processes occurring in the body.

Theoretical methods:

• Statistical method is based on statistical processing of quantitative material collected as a result of other studies (observations, experiments, modeling), which allows for a comprehensive analysis and establishment of certain patterns.
• Modeling- makes it possible to study objects and processes that are difficult or impossible to reproduce experimentally, or to directly observe.

Practical lesson No. 1

Topic: “Research methods in biology”

Goal: to study the basic research methods used in biology; learn to use the acquired knowledge to solve specific problems

Theoretical provisions

Biology studies living systems using various methods. The main ones are observation and experiment, important ones include descriptive, comparative and historical methods; Currently, statistical methods and modeling methods play an increasingly important role in biology.

Observation- the starting point of any natural science research. In biology this is especially noticeable, since the object of its study is man and the living nature around him. Observation as a method of collecting information is chronologically the very first research technique that appeared in the arsenal of biology, or rather, its predecessor, natural history. And this is not surprising, since observation is based on human sensory abilities (sensation, perception, representation).

Observations can be direct or indirect, they can be carried out with or without technical devices. Thus, an ornithologist sees a bird through binoculars and can hear it, or can record sounds with the device outside the range audible to the human ear; a histologist observes a fixed and stained section of tissue using a microscope, and, say, for a molecular biologist, the observation may be recording changes in the concentration of an enzyme in a test tube.

In observation, not only the accuracy, accuracy and activity of the observer is important, but also his impartiality, his knowledge and experience, and the correct choice of technical means. The formulation of the problem also presupposes the existence of an observation plan, i.e. their planning.

Experimental method The study of natural phenomena is associated with active influence on them by conducting experiments (experiments) under controlled conditions. This method allows you to study phenomena in isolation and achieve repeatability of results when reproducing the same conditions. The experiment provides a deeper insight into the essence of biological phenomena than other research methods. It was thanks to experiments that natural science in general and biology in particular reached the discovery of the basic laws of nature. Experimental method serves not only to conduct experiments, obtain answers to questions posed, but also to prove the correctness of the hypothesis accepted at the beginning or allows you to correct it.

The full cycle of experimental research consists of several stages. Like observation, an experiment presupposes the presence of a clearly formulated research goal, a plan, and is based on presets, i.e. starting positions. Therefore, when starting an experiment, you need to determine its goals and objectives and think about the possible results. A scientific experiment must be well prepared and carefully conducted. In addition, the experiment requires certain qualifications of the researchers conducting it.

At the second stage, specific techniques and means of technical implementation and control are selected. In the last half century, methods of mathematical planning and experimentation have been widely used in biology. The results of the experiment are then interpreted, which makes it possible to interpret them. Thus, the design, design, and interpretation of experimental results depend much more on theory than the search for and interpretation of observational data.

Having collected factual material, it is necessary, first of all, to describe it. Therefore, biological observations are always accompanied by a description of the object being studied. Under the empirical description is understood as “the recording by means of natural or artificial language of information about objects given in observation.” This means that the result of an observation can be described in numerical terms, with formulas, as well as visually - with the help of drawings, diagrams, graphs. A fact obtained as a result of observation can be ambiguous, since it depends on many surrounding circumstances and bears the imprint of the observer, the place and time of the event. Therefore, strictly speaking, just from the presence of a fact, its truth does not follow. In other words, facts need interpretation.

Work on the description of living nature, carried out in the 16th–17th centuries. in biology, was of great importance for its development. She opened the way to the systematization of animal and plant organisms, showing all their diversity. In addition, this activity significantly expanded information about the forms and internal structure of living organisms.

Later, the descriptive method formed the basiscomparative and historical methods of biology. Correctly composed descriptions produced in different places at different times can be compared. This allows us to study the similarities and differences of organisms and their parts through comparison. Finding patterns common to different phenomena, having at his disposal the corresponding descriptions, a biologist can compare the sizes of mollusk shells of the same biological species today and under Lamarck, the behavior of moose in Siberia and Alaska, the growth of cell cultures at low and high temperatures, and so on. . Therefore, the comparative method became widespread back in the 18th century. Systematics was based on its principles and one of the largest generalizations was made - the cell theory was created.

Historical the method of studying natural phenomena clarifies the patterns of the appearance and development of biological systems, the formation of their structure and functions; is the basis for the creation of the theory of evolution. With the introduction of this method, qualitative changes occurred in biology: from a purely descriptive science, it began to transform into an explanatory science.

StatisticalThe method of studying natural phenomena is based on the collection, measurement and analysis of information.

Methodmodeling is the study of a certain process or phenomenon through the reconstruction of it (or its properties) in the form of a model.

These methods do not exhaust the entire arsenal of methods used in biology. Each biological science has its own methods for studying its subject. For example, microbiology uses microscopic methods, cultivation of microorganisms, and sterilization methods; in genetics - twin, hybridological, phenogenetic, population and others, which will be discussed in more detail in the following lessons.

The main stages of scientific research include the following:

Formulation of the problem.

Formulating the topic, goals and objectives of the study.

Proposing hypotheses (scientific assumptions).

Planning an experiment, choosing research methods.

Conducting the practical part of the study, recording qualitative and quantitative results.

Repeat the experiment many times for reliability.

Processing of the obtained results.

Analysis of the results obtained.

Formulation of conclusions, testing of hypotheses.

Determination of the range of unresolved issues.

Presentation of research results.

Based on the analysis of experimental data or scientific facts (events or phenomena that have been accurately established and repeatedly confirmed by the research of many scientists), a theory (a system of the most general knowledge in a certain field of science) or a law can be formulated - a verbal and/or mathematically formulated statement that describes the relationships , connections between various scientific concepts, proposed as an explanation of facts and accepted at this stage by the scientific community as being consistent with experimental data.

Tasks

2. Using the table “The most important dates in biology” (Appendix 1), fill out the fourth column of the table, giving 2-3 examples of the use of each method.

3. Select the three most important (from your point of view) events in development:

- microbiology;

- cytology;

- genetics.

4. The laboratory studied the effect of temperature on the growth of bacteria. After the experiment, the following data were obtained: at a temperature of 5ºC the number of bacteria was 30, at 48ºC – 140, at 70ºC – 280, at 80ºC – 279, at 100ºC – 65. Reflect these data in a table and graph. Describe the resulting pattern. Determine the optimal development temperature for this type of bacteria.

5. Draw up a rough experimental plan to study the causes of spoilage of any food product you choose, including the required points:

- brief description of the object, statement of the problem, formulation of the hypothesis;

- purpose and objectives of the work;

- factors you want to study;

- output parameters and methods of their control that you would like to use;

- number of repetitions of each experiment;

- possible options for presenting the obtained data;

- the possible scientific and practical value of your results.

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Annex 1

A method is a research path that a scientist goes through when solving a scientific problem or problem.

• Descriptive method. It is based on observation. It was widely used by ancient scientists who were involved in collecting factual material and its description (study and description of animals and plants), and is also used today (for example, in the discovery of new species).

Observation is a method by which the researcher collects information about an object (perception of natural objects using the senses).

Example:

You can observe visually, for example, the behavior of animals. You can use instruments to observe changes occurring in living objects: for example, when taking a cardiogram during the day, or when measuring the weight of a calf over the course of a month. You can observe seasonal changes in nature, the molting of animals, etc. The conclusions drawn by the observer are verified either by repeated observations or by experiment.

• Comparative method began to be used in the 17th century. It allows you to identify similarities and differences between organisms and their parts (systematization of plants and animals, development of cell theory). Nowadays, the comparative method is also widely used in various biological sciences.
• Historical method- establishing relationships between facts, processes, and phenomena that occurred over a historically long period of time (several billion years). This method helps to comprehend the obtained facts and compare them with previously known results. This method became widely used in the second half of the 19th century (substantiation of Charles Darwin's theory of evolution). The use of the historical method made it possible to transform biology from a descriptive science into a science that explains how diverse living systems originated and how they function.
• Experimental method- this is the acquisition of new knowledge (the study of a phenomenon) with the help of experience.

An experiment is a research method in biology in which the experimenter deliberately changes conditions and observes how they affect living organisms. The experiment can be carried out both in the laboratory and outdoors.

The experimental method began to be used in his research in the study of blood circulation William Harvey (1578-1657), and it began to be widely used in biology (in the study of physiological processes) in the 19th century. G. Mendel, studying the heredity and variability of organisms, was the first to use experiment not only to obtain data about the phenomena being studied, but also to test the hypothesis formulated on the basis of the results obtained.
In the 20th century, thanks to the emergence of new instruments for biological research (electron microscope, tomograph, etc.), the experimental method became leading in biology. Modeling, which is considered the highest form of experiment, is also used in modern biology (active work is underway on computer modeling of the most important biological processes, the main directions of evolution, the development of ecosystems and the entire biosphere).

Biology is divided into many special sciences that study various biological objects: biology of plants and animals, plant physiology, morphology, genetics, systematics, selection, mycology, helminthology and many other sciences. Therefore, along with general biological methods, there are methods that are used by special biological sciences:

• genetics - genealogical method of studying pedigrees,
• selection - hybridization method,
• histology - tissue culture method, etc.

A scientific fact is a form of scientific knowledge in which a specific phenomenon or event is recorded; the result of observations and experiments that establishes the quantitative and qualitative characteristics of objects.