The Teaching of Biology in Basic Education from the Perspective of Developmental Teaching

Logical-subject analysis of the substantive area which is to become the students’ subject of study requires reconstruction of the historical path of formation of human knowledge in this area. The real logic of the development of the notions is hidden behind the paths of the historical development which seem winding and dark to us. Thus the reconstruction of the history of biology is necessary in order to consider the way scientific terms developed and to reveal the initial “cell” which was the germ of these notions.

The first thing that becomes obvious when one tries to consider the contents traditionally studied in school biology course is that a few historically separate areas of knowledge are included in it. Anatomy and human physiology, botany and zoology, understanding of the evolution of life on Earth, genetics – all of them arose and developed within extremely heterogeneous practices: medicine, agricultural activities, geography, hunting and farming, etc. Therefore, a few subjective lines can be obviously distinguished in the school biology course, so it seems impossible for only one developing notion to be its basis.

Thus, the attempt to build biology course in primary school requires, first and foremost, revealing of not the only one, but of a few basic notions / substantive areas / models which are to define the contents of the future study course. Even L. S. Vygotsky at the time, building the theory of systemic structure of consciousness (1), pointed out at the significant difference between any study course in teenage school and study course in primary school.

Here we will consider the method of constructing of one subject line – the development line of the notion of organism.

The notion of organism is one of the key notions in any school biology course. Not less than 80 academic hours are dedicated to its initial formation in our course. It is necessary to make logical-subject and logical-psychological analyses of the content of this notion in order to construct student’s learning activity aimed at the understanding of the notion (2).

Let us refer to the history of science. A separate living being, considered as an organism, initially seems to the researchers as a “black box” transforming air, water and food it receives. How to understand its structure and work? Of course, it can be killed and dissected.

Anatomists went this way and, due to their research works, the notions of “systems” and “organs” as living beings’ body parts which are very different from others by their form and can be separated without severe damage appeared.

With this method of research, however, living being loses its characteristic of being alive, so nothing but the mysterious interwoven structures can be found out this way. Thus, another way, the main way of research which, historically, was formed later, consists of experimenting and modelling of connections between functions and structures through comparing this “black box” to analogical, but understandable transformers.

This is the way of physiologists, due to their works the knowledge of functions of living beings’ bodies, changes of their conditions and interrelations between works of structures was developed.

Thus, the logical-subject analysis shows that the comparison of "the absorbed" and "the emitted" by body and the detection of processes similar by the nature of transformation of what is received by the “black box”, but more visible for human eyes, thus more available for research, became the first steps in search of the initial “cell” for the subject area.

Due to the research of air and its transformation in the body of a living being which was started by Lavoisier, Séguin, Priestley and Scheele, it was discovered that the pivotal process connecting basic vegetative functions of organism together is breathing. In this process the chemical energy of organic substances received during heterotrophic nutrition (by animals, bacteria and fungi) and during autotrophic nutrition (by other bacteria and plants) is transformed into the energy which is available for living being and can be consumed for its needs.

In the process of breathing oxygen is absorbed from external environment and then spent, and then carbon dioxide and water are produced and emitted. The same researchers mentioned above discovered that process of burning available to immediate observation is analogical by its “absorption” and “emission”. In the process of burning of, e.g., wood, paper, etc., oxygen is spent, the chemical energy of organic substances transforms into the energy of light and heat, carbon dioxide and water are produced. Thus, the “sense” of the process of cell breathing which is unavailable to immediate observation can be distinguished from the analogy with the process of burning.

Further on, however, significant differences between breathing and burning are found: in order to implement breathing, oxygen, carbon dioxide, water and organic substances should be brought across the border of living being which separates it from the external environment. The difference between living being and non-living space is in the presence of the internal environment separated from the external one and hidden from external observation. Thus this border with its contradictory features (to hold and to pass) becomes the initial “cell” of the notion of organism which fixes this interrelation between internal and external environments.

Concretization of the concept of the border includes the study of cell membrane with its selective permeability and of multicellular organism’s border in its diverse forms.

Structures and shapes of living beings’ bodies which change the spatial relationships of the internal and the external are modified simultaneously with the transformation of the border. Parts of the border, curving, “hide inside”, so the internal environment appears “inside of the body”. This is, for example, the air in the lungs, or the contents of our intestines.

The border as a structural element is the method of the particular “bonding” of the functions1This wording belongs to B. D. Elkonin.. Concretization of the concept of the border determines the formation of the notion of organism by students for it implies the study of the diversity of structural variants of the organization of living beings’ bodies. The more specifically we understand the border, the deeper we go into the details of its possible structure, the wider the given and understood by us diversity of the variants of possible structure and functioning of the organism is.

Understanding of the concept of organism allows one to perform the following actions: to interpret the results of experimental studies of structural-functional relations, i.e., to build meaningful hypotheses-conclusions; to construct (to imagine, to describe hypothetically) the structures fulfilling vegetative functions, as well as to design their artificial substitutes; to distinguish vegetative functions of structures based on the features of their structures and place in the living being’s organism. In simple terms, a person who understands this notion can also understand how the body of animal (including human), plant, and fungus is built and how it works. And if something remains unclear, one can formulate exact questions to search for supplementary information or to set up an experiment.

However, understanding of the internal organization of the material which is to be learnt by students does not mean building it the way this learning would become possible.

Logical-psychological analysis requires correlation of age features of consciousness, thinking and personality of students with the logical structure of the material which is to be learnt and its representation in the form of a system of educational tasks. According to D. B. Elkonin, notions cannot be learnt; knowledge cannot be just attached to the subject. Learning of notions happens in the educational activities in the process of active reproduction of the logic of reduction of the facts observed to the initial relations and the subsequent concretization of this notion by students.

In this case, the process of “reduction” of the facts studied to the initial relations should be extended in time, almost like it happens at the very beginning of studying subjects at school, in the first grade (the period of studying math “before the numbers” or the period of learning how to read “before the letters”). The objects of studying themselves are perceived as very heterogeneous by students: I (human); animals (my cat, elephant, dinosaur, etc.); plants (potato, baobab). All these objects seem to children like they are “from different fairy-tales”. It is hard for students to accept the homogeneity of the facts related to this diversity.

The duration of the period of “reduction” is also related, firstly, to the fact that students are not familiar yet even with a limited range of phenomena, basic models and experimental methods of activities which are significant for the beginning of the work in this area, and secondly, to the fact that, on the contrary, students are found to be considerably aware, they use biological, chemical and physical terminology combined with naturalism of perception and thinking in this knowledge area in their everyday life. We can see this naturalism, for example, in the fact that the majority of 5-6 grade students have heard that “everything consists of molecules”. However, they usually give molecules the properties of a living being, especially if they find out that molecules move. So, for instance, molecules move faster when the body is being heated “because it is hot”. Carrot consists of “molecules of carrot”, dough consists of “molecules of dough”, etc.

To construct the initial “cell”, it is necessary to have: 1) basic understanding of substances, molecules (organic and inorganic) and the character of their movement; 2) basic understanding of chemical transformations of substances; 3) basic understanding of energy, its types and transformations of one type into another; 4) the ability to interpret the results of experiments and distinguish between the results of an experiment and its conclusion; 5) basic skills at modelling, like, for instance, the ability to replace the relationship with the symbols and signs, the ability to interpret the differences in the symbols and signs as a reflection of real differences, etc. All these make requirements to the construction of the introductory course very tough for we do not have the opportunity to rely on a sufficient level of students’ understanding of the areas which are traditionally studied within physics, chemistry and further.

Except for the problems of coordination of biology, physics, chemistry and mathematics described above, a number of other age- and psychological-related difficulties arises.

First and foremost, it is important that the real object on the basis of which it is logically convenient to study the “simplest” variant of the border, namely the cell, is disproportionate to human’s body. The cell is too small, it can be seen only through the microscope, and the border of the cell, the cell membrane, can be seen only through the electron2Note for those who have not used this device in their work: electron microscope is not to be confused with digital microscope – almost every school has digital microscopes now, in contrast to electron microscopes - only corresponding research centers use them. microscope. In our case, it significantly reduces availability of the object as the subject of students’ research. It is necessary to organize special students’ activities (calculation of the size by its scale, imaging of the sizes “with their own hands”, i.e. bodily representation) only in order for students to imagine the sizes of this object. Thus, the search of other natural objects with which the students would work (research them, transform, imagine, discuss, etc.) is necessary. Obviously, each of such objects is “partial”, i.e., in contradistinction to the cell, is suitable for studying only with one of its sides, thus these objects should be correlated, represented to the students “in the same field”.

The complexity and inaccessibility of the objects under study requires the simultaneous discussion in different modelling languages and, of course, it also affects the duration of the period of the “reduction” of the diversity of the facts to the initial cell for the students learn these modelling languages in the process of work. Let us name them.

a) The first language which is necessary for the discussion of work with biological objects and for understanding of them is the language of schemes (including molecular schemes, functions relations circuits, etc.) which allows to relate different plans of actions, to represent for oneself and for others the task set. The example of such schematic representation is shown in fig. 1 – these are two molecular schemes revealing students’ controversial understandings of the border of living organism. Such a border dividing the internal and the external environments is absent in figure A and is present in figure B, but it “does not consist of molecules”. The fixation of different points of view in form of the molecular schemes allows students to fixate the nature of the revealed controversy clearly and to set the research task which would have been impossible if students formulated their opinions only in a verbal form.

b) Another language which is to be learnt by students studying biology at any programme is the language of schematic biological images, slices and micrograph photos which the majority of students learning traditional courses of biology at school do not perceive as a language until they pass their middle school exams, thus the objects represented this way seem natural to them. The images in textbooks at school seem to them as images of real objects, i.e., for instance, 95% of adults having studied biology at school say the form of amoeba is flat "pancake".

The red and blue colours on the images of circulatory system means to many people that arterial blood is red and venous blood is blue or almost blue. The image of two capillary networks in circulatory system of fish (to the left and to the right of the fish's silhouette, fig. 2) means that one net is in the head and another one is near the tail, etc.

The work on formation of skills of reading such schematic drawings, microscope slides and photos must take place on biology lessons during discussions of not only the content of the drawings, photos and microscope slides, but also of how this drawing was obtained. The method of obtaining (producing) a drawing, a microscope slide or a photo should be clear to a student. Here is the example of how such work is undertaken in this course.

On one of the lessons with 12-13 year-old students while firstly introducing amoeba to them the teacher offered them four micrographs of amoebae. Then the teacher asked: “How many living beings are there on these photographs?” The opinions of the sixth graders were divided. Some of them believed that there were four amoebae; others believed that there was only one. All who believed there were four amoebae motivated it with the fact that the shapes were different, so the beings are also different.

But those who suggested that there was one living being had different points of view. One child explained that amoeba has complex shape and it was photographed from different sides, therefore it looks different. Another child disagreed and suggested that the amoeba crawls, changes in form, so it was photographed at different times.

The dispute was resolved after watching the animation "Movement of amoeba". Students found out unexpectedly that both of the disputants were correct: they saw that the shape of amoeba changes, but the assumption of various perspectives was also justified for it is possible to take pictures at the same time from four angles. And, most importantly, the discussion about different angles of shooting helped the students to imagine what amoeba looks like in volume.

c) The third “language” which is to be studied by the students is represented by different dynamic variants of modelling: the use of movable magnets, in contrast to circles in the schemes; work with interactive resources; use of movements and gestures while representing the dynamics of the processes, also the use of clay modelling allowing to imagine and compare the scales, the changes of forms of objects, correlation between the internal and the external.

d) Finally, the fourth "language" - the language of model objects, i.e. natural objects that are substitutes of the real ones (e.g., such as polyethylene, cellophane and gauze border between environments), which allow, on the one hand, to model the studied features of living beings, and on the other hand, to discover features excessive for the substitution of real objects while working with them on practice (fig. 3).

This or that solution of the tasks of overcoming naturalism, of studying basic modelling means, of broadening children’s views on the subject studied and the range of actions transforming the object observed, turning it different sides, leads to a rather rigid logic of the introductory course building. Usually the methods of schematization presented in the course are the result of hard searches that have passed multiple tests in the classroom. A fragment of one story like this is presented in a series of pictures from the lesson (Fig.4-6), in which project developers thanks to the work with students found deficiencies in the schematization and after the lesson discussion between the developers continued.

Thus the character of modelling is extremely important to build the logic of students’ consistent discoveries. The modifications of the schemes built which seem small at first glance can lead to irreversible and not always predictable consequences for the future educational movement of the class.

Let us now consider the logic of the introductory course, the content of which is already tested many times.

The basic steps of the joint educational movement of the class as a learning community while detecting the initial "cell" of the future notion of organism should be as follows:

1. Detection of the students’ initial views about living beings. The answer to the question: what does a living being need for life? Fixating of these views in written form.
2. Detection by the students of the fact that they don't know the answer to the questions: why do we need air, why do we need food, why do we need heat, etc.
3. Search of answers to these questions (starting with, by the teacher’s suggestion, the question about air3The question of why do we need air turns into a question about how the air is transformed in the body of a living being. This allows us to discover the process of respiration (cellular respiration) the shortest way, to identify its meaning and to proceed to the analysis of the border as the contradictory structure, as the linking function.).
4. Forming, fixing and testing the hypotheses about the nature of the transformations in the body of a living being.
5. Discovery of energetic sense of breathing and detection of the processes serving it.
6. Consideration of processes serving breathing (gas exchange, nutrition, excretion) as functions of the border of the body of a living being.
7. Problematization, designing and study of properties of "simplest" border of the body of a living being.

Table 1 presents the questions that arise in class when the organization of discussions by the teacher is skilful and the answers obtained mainly through jointly conducted experiments. In the third column of the table the main difficulties in students’ understanding in this period of time, i.e. their natural and worldly views that require modification, are highlighted. Sometimes a sudden discovery helps. And sometimes there is no sudden insight, but the modification of the initial naturalistic views requires long consolidation in the minds of the students either way.

Table 1. Approximate logic of the cognitive movement class during the introductory module.

How is the central learning task of this course set? The teacher helps the class to understand and to sharpen the fundamental contradiction of the border of the body of a living being, which is initially being introduced abstractly when discussing the questions about interrelation between the compositions of the external and the internal environments of a living being.

The initial scheme of the boundary looks like this:

The contradiction is that the border must simultaneously hold the internal environment which differs in features and composition from the outside one, and pass some substances through itself, in particular: gases of the air, water and organic substances needed for cellular respiration. Only individual students (or not a single student from the class) are aware of this contradiction when drawing the initial scheme. To make children aware of this contradiction (to make them feel it), the teacher emphasizes it fixing conflicting points of view of the students on the properties of the border (both orally and in writing) and helping students to formulate new arguments for both one and the other points of view.

Here is an episode from a lesson with 12-13 year-old students.

A beautiful photo of a sea jellyfish is shown to the students on the screen. The teacher asks: “What do you see on the screen?” “It is a jellyfish”, answer the students. “It is a jellyfish in sea water”, they reply after a pause.

The teacher shows diagrams of the internal and external environments of jellyfish. The students and the teacher discuss what is represented on the two diagrams. The students verbally describe the internal environment of the jellyfish and the composition of the sea water in which it lives, they compare them.

Then each student must draw a "molecular picture" of where the edge of the body of the jellyfish comes in contact with sea water. The kids do not know about cells and their structure yet, but they already know about molecules and diffusion.

The pictures in the classroom look pretty typical – approximately as in Fig. 1 (above). The students were asked to draw a "molecular picture", so there should be no "demolecularized" lines, both jellyfish and the sea water consist only of molecules4At this initial stage of studying science, students have the view which is not altogether correct.. Once this is clarified, the teacher asks a few students to come to the blackboard and represent such a scheme with the help of magnets. Magnets can be moved, so the students show the diffusion of molecules of the substances of jellyfish’s body and molecules of sea water, i.e., the dissolution of the jellyfish in the water. But this is impossible!

This way students start feeling the issue of the border, of what it is and of how it works. The teacher keeps sharpening the situation: what does the border of a living creature look more like – like gauze or polyethylene?

Gradually, the students realize the contradiction and formulate it on their own, for example: "This is a paradox! The border passes some molecules and does not pass some others!" Or this way: "Perhaps, some parts of the borders can pass molecules and some parts cannot."

The contradiction is fixated by the students in written form, and then a number of works which might help to solve this problem is offered to them. These are “parallel” works, in the sense that, in relations to each other, they are modelling, they basically answer the same question:

1. Experiment with carrot, in which it is found that the root of the carrot has a border through which water passes freely, but salt cannot pass5It is not exactly pure experiment for in its process the students do not notice that salt does pass. But this is another way (by apoplast) which has nothing to do with the problem; therefore it is fortunate that it is not very noticeable. . At the same time, "the dead", the cooked carrot does not possess such properties.
2. Experiments with the boundaries made of polyethylene, cellophane and gauze, which revealed that the polyethylene is impervious to an aqueous solution of iodine and starch, gauze is permeable, and cellophane is semi-permeable as the iodine penetrates through the plastic border and does not penetrate through starch. It can be detected by the fact that there is a change of colour of the starch and no change of colour on the side of the cellophane border where there is only iodine solution.
3. Virtual experiment in which the border of the drawn "bubble" behaves the same way as the border of a living being of the carrot.

In the process of doing these works, explanation of the things happening is conducted with the help of molecular pictures, both drawn and dynamic (fig. 8). Students move the magnets which denote different molecules, showing how chaotically they move; explaining what happens at the molecular level if we see the change of colour of the starch solution in our observation, or if, on the contrary, nothing changes; if there is the spread of odours and the like. Working with magnets allows pupils to highlight their lack of understanding or, on the contrary, imagine the course of the process observed clearer.

In the analysis of the experiment with cellophane the students discovered semi-permeability of the border, for cellophane passes only small molecules and holds the large ones, i.e., sorts them by size. Students understand this phenomenon better because something similar exists in their everyday experience. E.g., colander passes water, but holds pasta.

The experience with carrot shows, however, that the real border of a living being sorts molecules not by their size. For the molecules6These are not molecules, but it is early to tell the students about ions. of salt do not pass and the molecules of water being close to the latter by their size easily pass through the border. The new phenomenon discovered by children is called selective permeability by the teacher. Selectively permeable border becomes the basic structural and functional element of the notion of organism being built. Later, students are introduced to the cell membrane, as a natural embodiment of such "simplest" border, and try to apply the developed scheme to the analysis of processes of particular animals.

Sources

Выготский Л.С. Собрание сочинений в 6-ти томах, - М.: Педагогика.

Давыдов В.В. Теория развивающего обучения. - М.:ИНТОР, -1996, -544 с.