Harmony and Conflict in the Living World - Alexander F. Skutch [24]
As evolution proceeded, the primitive cells, instead of separating into independent halves after each fission induced by their increasing size, remained in contact and gave rise to multicellular organisms. As these aggregates of cells grew in bulk, those on the outside were exposed to conditions different from those near the center, and this diversity of situation induced differences in structure and function. Distinguishable tissues arose in these early organisms, and with continuing evolution diverse tissues were grouped into distinct organs. Eventually, animals and plants were equipped with a great diversity of organs, external and internal, each with its own marvelously complex structure and its particular function in the economy of the whole organism. To ensure the proper coordination of these separate organs and functions, each so necessary to the welfare of the whole body, integrative devices developed in the form of the nervous system and an array of chemical messengers which, released into the circulatory system by one organ, effected correlative modifications in others, often widely separated from the first. And while this internal development was proceeding, the whole cellular community remained sensitively responsive to modifications in its surroundings, for its prosperity depended, above all, on close adjustment to the environment that sustained it.
Thus, life could not appear until it found a fairly stable environment. From first to last, its evolution has depended upon harmo-
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nization, not only for the close integration of an increasing multiplicity of parts but likewise for adjusting this manifold to its ambience. Life arose out of harmony; it is a constant endeavor to preserve and increase harmony; it languishes or perishes with the failure of harmony, either in its internal arrangements or in its relations with its milieu. How, then, did this tender and delicate thing, this triumph of harmonization, ever become capable of violence?
Strife arose from the collision of patterns growing up at separate centers and incapable of coalescing into a single whole. Such fusion was impeded by the integument in which each living unit found it expedient to enclose itself in order to carry on its intricate processes without much interference from outside. Moreover, the complex molecules of the living substance, although exhibiting a fundamental similarity in chemical constitution, soon acquired different structures in diverse organisms, so that the simple fusion of distinct masses of protoplasm was no longer possible. The great profusion of life, the tendency to initiate these patterns of superior complexity and integration everywhere on Earth's surface that they could exist, inevitably resulted in the clash of living things, which is but a special instance of the general truth that the excessive intensity of the impulsion toward harmony gives birth to disharmony.
Increase in the number of organisms not only resulted in more frequent physical contacts between them; so many living things absorbing nutrients impoverished the medium and made the maintenance of life more difficult. Conditions were approaching an impasse that might have blocked the evolution of life had it not been broken. Finally, some of the primitive organisms developed the capacity to break down the substance of other organisms, take it into their bodies, and incorporate it into their own protoplasm. Possibly at first they used only dead organisms in this way; but since many of the protista multiply by simple fission and probably never die of old age, lifeless protoplasm might have been available only where the