With the concept of hierarchic organization, it becomes possible to gain a new insight into, and understanding of, the biological realm.

In the classical view, just as simple substances in nature are conceived of as being formed by molecules and atoms, biologically complex organisms are considered to be composed of cells as fundamental entities. In arriving at complex organisms, however, it is granted that organization has followed a definite pattern. At first glance, it is apparent that cells are grouped in morphologically regular ways to form tissues. Similarly, tissues are grouped to form organs and these in turn compose the organism. In this classical systematization, a complex individual would appear to be the result of a grouping of cells, tissues and organs, bound together in what has been described as an harmonious morphological relationship.

In our study of organization of the biological realm, we have emphasized the individualization of both conceptual and material entities. In some cases, entities have been simple to identify because they are easily separable morphologically. Where morphological separation has not been immediately evident, other criteria—such as structural and functional properties—have been used for identification. Besides playing its part in organization, each entity has its own individuality, and consequently can be recognized holistically as a well defined unity. Starting with chromomeres, the entity status is easily accepted because, in addition to clear morphological and functional properties, there is a degree of independent individuality. Following up, chromonemata, chromosomes, nuclei are other entities.

The study of the organization of biological entities has shown, however, that in all cases there is a specific pattern of interrelationship which is more complex than the classically accepted pattern. In the simplest microscopically identified entities, it could be seen that a series of chromomeres are bound together through a special fibrillar formation, which stains differ entiy from the chromomeres, to produce the chromonemata (1, 2), which can be considered holistically as a new entity. Two or four chromonematas (3), together with the chromosomal sap, form the chromosome as a new entity. Similarly, several chromosomes together with another part—this time represented by the nuclear sap and the proper nuclear membrane—form a nucleus. In turn, the nucleus, plus protoplasmic formations, cytoplasm and the cellular membrane, form the cell. Even superficial analysis indicates a common fundamental pattern in the organizational changes taking place for entities ranging from chromomeres to cells. Because of this pattern, these entities can be considered to be "hierarchically" interrelated. One entity is hierarchically "superior" to the entities which form it and "inferior" to those it will itself help form. Two immediately interrelated entities thus are hierarchically superior and inferior, respectively, just as in organization in other realms. (Fig. 1)

Analysis of the progression of organization from simple to more complex entities permits us to recognize other characteristics of the fundamental pattern. In order to form a hierarchically superior entity, several similar entities first join to form a group. It is the group which then will bind other constituents to bring into existence a new, hierarchically superior, biological entity. Thus, the chromomeres as a group join with a fibrillar formation to produce chromonemata; chromonemata join with chromosomal sap to form chromosomes. Groups of chromosomes plus nuclear sap form the nuclei. It has appeared evident that the parts which are bound to form each hierarchic entity do not play equal roles. In each case, the principal part is the one which is composed of similar entities acting as a group; the other part is the secondary. Figure 2 offers a graphic representation of hierarchic organization from chromomeres to cells.

In all entities, mentioned above, there is the same relationship between principal and secondary parts. The secondary surrounds the principal part. The morphological relationship has helped us to apply to those entities the hypothesis discussed previously concerning the mechanism through which hierarchic progression has taken place in nature. According to the hypothesis, several similar entities would first associate and form a group. In a second step, the group would tend to maintain around it a small portion of its immediate environment. From this portion of the environment would come the secondary part for the next superior hierarchic entity. With a boundary formation, separating this minute part from the rest of the environment, the new entity would be established. Such a process could occur, although rarely, with a single biological entity serving as principal part. Usually, several entities grouped together would be needed. This pattern explains why the secondary part can be conceived of as a part of the environment retained around the principal part, and why the establishment of a new and higher entity can be considered to occur only when this secondary part is detached from the rest of the environment and separated from it through the intervention of a boundary formation.

The hierarchic relationship in the organization of morphological entities

Fig. 2. The hierarchic relationship in the organization of morphological entities below cells. For each entity its principal part is recognized as being made by a grouping of entities hierarchically inferior to it. The secondary part which corresponds to a kind of environment for the principal part usually surrounds the principal part.

Having recognized this pattern of organization for lower entities, we went on to determine whether it remains the same for higher entities. It could be seen that groups of cells, along with interstitial formations and fluids around them serving as secondary part, create the tissue as a new hierarchically superior entity. Indeed, a proper boundary formation morphologically limits and conceptually defines the new entity. The interstitial fluids are separated by a continuous endothelium limiting the lymphatic spaces as a system closed toward the intercellular spaces. Under these circumstances, the lymphatic endothelium serves as the corresponding boundary formation that limits the tissue entity. Several tissues grouped together, playing the role of the principal part, bind the lymph, as secondary part, to form the organ, as a new hierarchic entity. Lymphatic vessels and connective tissues represent the organ's boundary formations. Furthermore, organs grouped together, with blood as secondary part, form the entity called the organism. (Fig. 3)

Does the same pattern apply for entities hierarchically inferior to chromomeres? For these lower entities, morphological information to define the relationship between principal and secondary parts is unavailable for the moment. Until electron microscopy and other means provide such data, we are obliged to find other criteria to indicate which, in these hierarchic entities, is principal and which secondary part. We have considered electrical characteristics of the constituents as criteria for identifying their role in the hierarchic organization of biological entities below chromomeres.

The oganization above the cells

Fig. 3. The oganization above the cells. The hierarchic pattern of the organization in general is recognized also in the organization above the cells. Tissues, organs, organism are seen to represent hierarchic entities, each one being made by a principal part formed by the grouping of entities hierarchically immediately inferior to it. The principal part is bound to a secondary part characteristic for each entity. This secondary part would correspond to the proper environment in which the entities forming the principal part, have evolved.