All stated in this Chapter shed light on two very important general
biology problems. They are presented in Figure 4–6.
unicellular to multicellular organisms (A) and regeneration of a whole
multicellular organism from a somatic cell (B).
The first problem is relevant to the formation and development of
multicellular organisms in evolutionary aspect. From the brief survey the
logical conclusion follows, that multicellular organisms are a product of
association (integration) of single cells, existed before as independently
organisms. In the course of evolution they form coenobial and colonial
forms, encircled by a common mucous cover. On this cover there are
pores connected with channels through which the connection with
surroundings, taking and excretion of substances are realized, and in the
interior the cells are connected with cytoplasmic fibres. Gradually, the
integrated cells specialize and differentiate by forming different tissues
and organs performing specific functions. In the beginning the coenobial
and colonial forms reproduce asexually or by budding, and then the
sexual reproduction arises where two types of cells strictly differentiate
— vegetative (somatic) and reproductive (sexual). Undoubtedly, the
process of forming multicellular organisms possesses polyphylic
character. Some of the lines disappear, other come to a “dead-end” and