Biological organization

“ Now, then, what is the first, the simplest form of organization—the primordial type of organic creatures? It is a cell. For, notice what is really meant by an organism—an organized creature. It is a creature that has functions dependent upon organs or parts. There is, then, in the very simplest organism already a manifestation of Von Baer's great law in biology—differentiation. Without differentiation there is no organization, and without organization, again, no life. ”

“ It must not be forgotten that the germ is the entire organism and that it passes through development as the same individual; continuity of individuality is preserved throughout development. Therefore, if we discard determinant hypotheses and take our stand on a strictly physiological theory of development, it follows of necessity that the transmitted factors of heredity included in the organization of the germ cells must be factors in the development of the entire organism. ”

“ Resting upon the law of the division of physiological work, the importance of which was first demonstrated by Milne-Edwards, and upon that of polymorphism, which without it have only a limited and indefinite meaning, consequent on the law of division of protoplasmic masses, it has been the great producer of organization, and establishes a new link between sociology and the branches of biology that are occupied with the constitution and functions of organisms. ”

“ All animals therefore, I contend, have a similar cause of their organization, originating from a single living filament, endued indeed with different kinds of irritabilities and sensibilities, or of animal appetencies; which exist in every gland, and in every moving organ of the body, and are as essential to living organization as chemical affinities are to certain combinations of inanimate matter. ”

“ It is a physiological fact, he says, that organs are increased in size by action, atrophied by inaction; it is another physiological fact that modifications produced are transmissible to offspring. Change the actions of an animal, therefore, and you will change its structure, by increasing the development of the parts newly brought into use and by the diminution of those less used; but by altering the circumstances which surround it you will alter its actions, and hence, in the long run, change of circumstance must produce change of organization. ”

“ A SINGULARLY instructive field for the study of the mutability or stability of species should be afforded by the lower forms of life, in which organization is reduced to a minimum, they being mere masses of protoplasm without even a containing envelope, while their nourishment is of the simplest. ”

“ But the study of the relations of the organism to its environment, organic and inorganic, also belongs to physiology in the wider sense; we call this part of it perilogy, or the physiology of relations. To this belong chorology, or the science of distribution (also called biological geography, as it deals with geographical and topographical distribution) , and œcology or bionomy (also recently called ethology) , the science of the domestic side of organic life, of the life-needs of organisms and their relations to other organisms with which they live (biocenosis, symbiosis, parasitism) . ”

“ On this condition only does the process of organization appear possible. We might almost say that just as some race of animals, which multiplies and spreads into divers regions of the earth, becomes differentiated into several races through the adaptation of each to its conditions of life; so, the originally homogeneous population of cells arising in a fertilized germ-cell, becomes divided into several populations of cells that grow unlike in virtue of the unlikeness of their circumstances. ”

“ It results that the multiplied repetitions of these acts of organization strengthen, extend, develop, and even create the organs which are necessary. It is only necessary attentively to observe that which is everywhere occurring to convince ourselves of the well-grounded basis of this cause of organic developments and changes.
“Moreover, every change acquired in an organ by a habit of use sufficient to have produced it is then preserved by heredity (génération) if it is common to the individuals which, in fecundation, unite in the reproduction of their species. ”

“ Impossible though it may be to imagine the natures of those ultimate units peculiar to each species, which have proclivities towards the particular form of organization characterizing it, yet that a change of structure arising in one part of the organism is accompanied by multitudinous changes of structure in other parts of the organism, is not only congruous with the belief that there exist such constitutional units, but yields it distinct support. ”

“ Whence it happens that, in the copulation of animals of different species, the parts necessary to life are frequently completely formed; but those for the purpose of generation are defective, as requiring a nicer organization; or more exact coincidence of the particles of nutriment to the irritabilities or appetencies of the original living filament. Whereas those mules, where all the parts could be perfectly formed, may have been produced in early periods of time, and may have added to the numbers of our various species of animals, as before observed. ”

“ The organization of the animals was simply the result of the combination of many independent units. There was no activity of the organism as a whole, but only of its independent parts. Cell life was superior to organized life. Just as, in a city, the city government is a name given to the combined action of the individuals, so are the actions of organisms simply the combined action of their individual cells. ”

“ They are supposed not only to regulate the special development and construction of every species of animal and plant, and direct it to a predetermined end, but also to control all the various movements of the organism and its organs down to the cells. ”

“ If we had begun our study with that of the lowest organisms, and had proceeded from these to the more complex ones, we should have seen the progression which is observable in organization, and the successive acquisition of various special organs, with new faculties for every additional organ. We should thus have seen that sense of needs—originally hardly perceptible, but gradually increasing in intensity and variety—has led to the attempt to gratify them; that the actions thus induced, having become habitual and energetic, have occasioned the development of organs adapted for their performance ”

“ On the contrary, if we begin with the end which comprises animals the most simple in organization, the poorest in faculties and in organs—in a word, the most imperfect in all respects—we necessarily remark, as we gradually ascend in the series, a truly progressive complication in the organization of these different animals, and we see the organs and faculties of these beings successively multiplying and diversifying in a most remarkable manner. ”

“ Let us take a brief glance at the various specializations and trade developments, which have taken place in the different groups of cells, and see to what extent the profound modifications which many of them have undergone are consistent with their individuality and independence, and also whether such specialization can be paralleled by actually separate and independent organisms existing in animal communities outside of the body. ”

“ That in her course nature has begun, and begins anew every day, by forming the simplest organic bodies, and that she directly forms only these—that is to say, only these first primitive germs (ébauches) of organization, which have been badly characterized by the expression of “spontaneous generations” (qu’on a désignées mal-à-propos par l’expression de Générations spontanées) .
“3. That the first germs (ébauches) of the animals and plants were formed in favorable places and circumstances. ”

“ Every organic cell is to a certain degree an independent organism, a so-called “elementary organism,” or an “individual of the first order.” Every higher organism is, in a measure, a society or a state of such variously shaped elementary individuals, variously developed by division of labour. ”

“ For these he depends on the labours of other specialists; and therefore the higher the state of civilization the more complete is the state of interdependence of the members of the community.
So in higher animal organisms we find that all cells have taken up special duties—have all become specialists. Every kind of cell performs one function specially well and the others not so well, or not at all. ”

“ But organization does not long rest on this low stage of unicellular simplicity, for, as we pass from these lowest forms into higher, we find cell added to cell, until many millions of such units become associated in a single organism, where each cell, or each group of cells, has its own special work, while all combine for the welfare and unity of the whole.
In the most complex animals, however, even in man himself, the component cells, notwithstanding their frequent modification and the usual intimacy of their union, are far from losing their individuality. ”

“ The distribution of labor, however, is not a uniform one, and we are not to suppose that the work performed by each cell is but a repetition of that of every other. For the life-processes, which are accumulated in the single cell of the unicellular organism become in the more complex organism differentiated, some being intensified and otherwise modified and allocated to special cells, or to special groups of cells, which we call organs, and whose proper duty is now to take charge of the special processes which have been assigned to them. ”

“ We thus arrive at the simple cell, and the multiplication of living beings by cell buds; it is the point at which the confines of the animal kingdom are reached, and at which we are driven to speculation. ”

“ In these multicellular animals each of the constituent cells is a minute self-centred organism, individually born, leading its own life and destined for individual death. The corporate power of the complex animal is the sum of the powers of those manifold individual existences, its cells. In the complex animal the several organs, even the most homogeneous, such as muscles or glands, are each composed of many thousands of cells similarly specialized but living each per se. ”

“ If the law of the animal cell, and of the animal organism, which is built up of such cells, is like that of the vegetable, we might expect that we should treat all morbid conditions of any of the vital unities belonging to an animal in the same way, by increasing, diminishing, or changing its natural food or stimuli. ”

“ In the same manner, the cells united in an organism share among them the labor of fight for existence of the whole organism; they magnify the power of one capacity, and weaken another, and unite in one organ, in order the better to supply the requirements of the whole organism. ”

“ Specialization in Higher Organisms.—If we pass on to the higher animals and plants which are not single cells or colonies of similar cells but organisms made up of many different kinds of cells, we find a pronounced extension of the phenomenon met with in Volvox. Instead of each cell executing independently all of the life relations, certain ones are set apart for the performance of certain functions to the exclusion of other functions which are carried on by other members of the aggregation. Thus the organism as a whole has all the life relations carried on, but, as it were, by specialists. ”

“ Here let me add that as, in the higher individual organisms, the aggregated cells which form the embryo, and for some time retain their separateness, gradually give place to structures in which the cell-form is greatly masked and almost lost, so in the social organism the family groups and compound family groups, which were the original components eventually lose their distinguishableness, and there arise structures formed of mingled individuals belonging to many different stocks. ”

“ A system, in order to be true and natural, must agree with the sequence of the organs in the development of the embryo.” If the earlier manifested peculiarities are to be estimated more highly than those which afterwards make their appearance, then in those cases in which the structure of the adult animal requires one position in the system, and that of the larva another, the latter and not the former must decide the point. ”

“ If the average amount of food which an animal can assimilate every day remains constant for a considerable time, it follows that a strong influx towards one organ must be accompanied by a drain upon others, and this tendency will increase, from generation to generation, in proportion to the development of the growing organ, which is favoured by natural selection in its increased blood-supply, etc.; while the operation of natural selection has also determined the organ which can bear a corresponding loss without detriment to the organism as a whole. ”

“ Cells or polyps, it always submits to the same elaboration in developing new individuals. The cells, once assembled in the organism, yield easily to the changes required by the division of physiological labor, and form various organs, although these organs never become true individuals. If the individuals of a colony often descend to the state of organs, we must not conclude that the organs of an animal are always individuals that have lost their autonomy ”

“ Hence the invariable character of the germ-cells. In bone-formation, it is clearly shown that special structure begins very early,—in the cell, namely; but it is preserved only where it is aided by the necessary action and reaction. Autonomic in itself, life submits itself to the general laws of evolution. [67] As the direction of motion is determined for whole groups of cells by the direction of the motion of the protoplasm in the single cells, so organic function is determined by the grouping of the irritable, contractile, sensible cells. ”