Part 4

FIG. 2.--Struggle for Existence on a Clam Flat. Showing the overcrowded condition of a colony of Soft Clams (Mya arenaria) on Rowley Reef, Massachusetts. The pits mark the position of the living clams. Photo. by Belding, loaned by Mass. Comms. Fisheries and Game. ]

The three methods of approach to ecological study are not so distinct as they appear at first thought. With perfecting knowledge the network of interrelations increases and the paths converge. Then also the study of the individual behavior of “social” animals, as ants, white ants, bees, or birds which live and breed in colonies, shows transitional stages from the individual unit to that of the family, the colony, and on to the association. Yet the advantage of each point of view should be recognized as an aid in the analysis and synthesis of any problem.

Some students feel that the study of individual ecology should precede that of the associational. Within certain limits this is true, but if our general knowledge of biology had waited for the perfection of our knowledge of the individual cells of animals, the results would have been disastrous to all concerned. Even now our knowledge of these subjects is very incomplete. For similar reasons there should be no delay in studying animal aggregates and associations.

A combination of ecological and taxonomic study generally appeals most strongly to those students who have made a specialty of some group of animals. They are familiar with certain forms, have some confidence in taxonomic methods, and frequently have given some attention to habits, life histories, and to collecting. To those who like the descriptive aspect of taxonomy, ecological studies also offer a new field for further description and classification. At present perhaps the majority of ecological students have entered the subject through taxonomy. It is the almost universal verdict of such students that it has required much effort on their part to make the change in the point of view. Such a change cannot be made by a simple resolve, but requires a modification of the habits of the mind, which will be attended by a distinct consciousness of effort. As in other habits, reversion to the older attitude of mind is very easy. This change in point of view is a problem in habit formation, a study of the mental behavior of the ecologist, which is in reality the main topic thus far discussed. One may attempt to make such a change and find that he does not have sufficient modifiability to make it permanent, so that it is only for the moment, during actual collision with some stubborn fact, that he is able to realize ecological relations and an ecological point of view.

FIG. 3.--Struggle for Existence on a Clam Flat. Showing the destruction of a colony of Soft Clams by Horse-shoe Crabs (Limulus) and Cockles (Lunatia), Rowley Reef, Massachusetts. Photo. by Belding, loaned by Mass. Comms. Fisheries and Game. ]

To the physiologist, however, individual ecology tends to appeal most strongly, and he, perhaps on account of the preponderance of analytical methods in his work, feels that this is the safest and most important aspect. This statement is perhaps also true of most students of animal behavior. This is largely due to the great present need of analytical methods in these lines, and perhaps indicates a stage in the development of their science rather than a permanent condition. Later a synthetic development will probably become more prominent, and with it will come a change in estimating relative values. Generally physiologists allow for a greater influence of the environment than do many other students. They are impressed with the dependence of organisms upon their environment, and the study of their reactions only reinforces this conception.

The ecologist who studies the responses of animals cannot help being impressed with the processes of adjustment, and with adaptation as a process. It is adaptation as a process, rather than as a product, which perhaps interests him most, and emphasis needs to be placed upon this distinction. The problem of adaptation as a process may be a different and separate one from that of evolution, but individual animals must have shown adjustive adaptation, or there could have been no perpetuation to continue the struggle of adjustment. Ecological problems are likely to raise a question as to the relative importance of adaptation and evolution--if they are separate problems. The present generation has perhaps been more deeply impressed by evolution as a process, than by adaptation as a process.

The ecology of living animals is only the latest chapter in the volume on this subject; the preceding chapters will contain a history of the indefinitely long series of ecological responses which have taken place in the geologic past. Here is where the ecologist and paleontologist and geologist find common ground. The ecology of living animals must furnish us with whatever firm basis we have for the interpretation of the conditions of life in the past, upon which the paleontologist, stratigrapher, or paleogeographer must depend, at least in part, for his interpretations.

With still another training and interest, as in the case of those especially interested in human affairs, such as the sociologist, the physician, the sanitary expert, and the agriculturist, we may ultimately expect a greater appreciation for the associational aspect because of the social or associational character of human society. The associational is the phase of animal activity which may be considered as the form of animal behavior which has developed into the human social relations. It is a response to the complete organic and inorganic environment.

It is rather natural that in a relatively newly recognized subject like ecology this human aspect has not been very fully discussed. For practical reasons the ecology of man has been developed largely independent of that of animals; just as human physiology and psychology have been developed relatively independent of comparative or general physiological psychology. To the mutual advantage of these subjects they are now rapidly converging, and we may anticipate a similar relation between general animal ecology and the ecology of man. In a general treatise on animal ecology the human phase should not receive undue emphasis any more than it should in a general physiology of animals or in a comparative psychology. But, nevertheless, the relationships of man and his animal associates (slaves, domestic animals, rats, mice, parasites, etc.) form as truly an animal association as do those of the animals which live associated in some forest glade; and in all probability, before any approximately complete understanding can be had of the human associations, their roots and principles of activity must be known and understood in the less aristocratic portion of his animal relatives.

The recognition of the associational aspect of ecology, as well as that human ecology is a part of general animal ecology, is of recent origin. This is very well shown in the following quotation from Huxley (1854. On the Educational Value of the Natural History Sciences):

“Biology deals only with living beings as isolated things--treats only of the life of the individual: but there is a higher division of science still, which considers living beings as aggregates--which deals with the relation of living beings one to another--the science which observes men--whose experiments are made by nations one upon another, in battlefields--whose general propositions are embodied in history, morality, and religion--whose deductions lead to our happiness or our misery--and whose verifications so often come too late, and serve only

‘To point a moral, or adorn a tale’--

I mean the science of Society or Sociology.”

At a later date (1876. On the Study of Biology) Huxley says: “For whatever view we may entertain about the nature of man, one thing is perfectly certain, that he is a living creature. Hence, if our definition is to be interpreted strictly, we must include man and all his ways and works under the head of Biology; in which case, we should find that psychology, politics, and political economy would be absorbed into the province of Biology. In strict logic no one can object to this course.... The real fact is that we biologists are a self-sacrificing people ... [so that] we feel that we have more than sufficient territory.... But I should like you to recollect that that is a sacrifice, and that you should not be surprised if it occasionally happens that you see a biologist apparently trespassing in the region of philosophy or politics; or meddling with human education; because, after all, that is a part of his kingdom which he has only voluntarily forsaken.”

Whether sociology is regarded as a response of man to his fellows or to the whole of his environment is inconsequential in its bearing upon whether or not it is ecological. The response of man, as an animal, to a part or the whole of his environment is strictly ecological. Huxley recognized one relation very clearly, and that is that the ecological relations of individuals do not currently include the higher synthesis which deals with them as associations, or “aggregates” as he terms them. So far as known to the writer, human activities in general have never been fully and comprehensively oriented from the ecological standpoint, even by the humanitarians themselves, although some important preliminary steps have been taken. It looks as if such a viewpoint might give a new unity to all studies of human relations.

There is still another class of persons, particularly teachers and isolated students, who desire first of all to understand and interpret their own vicinity, and who will inquire which of the three plans their work best fits. If such a one begins with the detailed study of each species, the general survey will not be completed during his lifetime. If he uses the larger taxonomic units, he may survey the field by going over the same ground again and again, with each of the different groups successively in mind, until the entire field has been surveyed. Or, lastly, he may divide the area into associations and study the animals which are found living together, and by studying one association after another he may cover the entire field. A teacher will find certain important advantages in this plan, and certain disadvantages. One of the most important considerations in its favor is that such a study results in a familiarity with the kinds of animals one actually finds in natural groups, as when his class is on an excursion. The natural history which a farmer, a fisherman, a summer vacationist, or a sportsman acquires is grouped in this same manner. Thus to a large number of people this is the natural method of approach, and is generally of most permanent value, except possibly to some professional teachers or zoölogists. One of its greatest disadvantages is that in most of the literature which one must use, the animals are not grouped in this way, but taxinomically.

The individual, aggregate, and associational methods of study are in themselves subject to diverse angles of approach, and each has its particular advantages and disadvantages. Of the methods of approach mention will be made of three only, the descriptive, the comparative, and the genetic or method of processes. The descriptive method must develop to some degree before the genetic problems can be adequately stated, and the mature development of the genetic may, and generally does, lag far behind that of the descriptive. The reason for this is simple, for it is evident that it is much easier to describe what we see than it is to explain how it originated or its process of development. At present biology as a science is mainly in the descriptive stage, though it is slowly but surely becoming explanatory and genetic. The developmental or explanatory method is so difficult that every possible expedient--observation, comparison, reflection, experiment, etc.--must be used to secure the proper development of the main phases of ecology. There is a marked tendency in the naturalist to master one system of work, as observation or experiment, and to use it as a tool almost exclusively, turning from one phase of the subject to another, and continuing the use of the same method. This way of working is favorable to a good technique, but its weakness is that it often tends to give its user a feeling of the great superiority and reliability of the result reached by his method, and a correspondingly less appreciative recognition of results secured by other methods. To observe, to experiment, to reflect, to dissect, to stain, and to collect are only partial methods of investigation, and this fact should be realized and be kept in mind when estimating values and planning work.

The aim of the ecologist is professedly genetic or explanatory because it is the study of responses to all conditions of the complete environment. But these responses must be described, and the conditions influencing them as well, so that a descriptive aspect is an essential part in all phases of ecology. In the study of the responses of an individual, an order, or an association, pure description of the responses is necessary; but a description which will at once describe and show the working of the processes by which the results were produced, is of quite a different order. This phase of explanation has been most concisely expressed and applied by the students of the physical sciences, and biologists may profit much from a study of their methods.

When, however, we turn to the viewpoint of the development of the science of ecology as a whole, a symmetrical development of the subject is most desirable. The preponderating influence of any special point of view tends, like dominance in general, to smother or suppress other germinating and competing ideas. The different special interests each have their advantages and disadvantages, as does a general interest. Diversity in students leads to diversity in the development of the subject, and a variety of emotional appeals to the student has its advantages. And just as the special student should devote some attention to the general bearing of his work, so also should the student of the general aspects cultivate some special field of interest.

The preceding discussion of the aims and methods in ecological study has been intended to indicate some of its general bearings, and to give the student some idea of the tests or criteria which may be used to aid in steering his course through the maze of observations which he may make and the opinions which he encounters. It is of equal importance for the student to be able to perceive ecological relations as recorded by others, because one person’s experience is so limited compared with the general body of recorded fact and inference. Furthermore, there are also so many degrees and kinds of work that go by the name ecological, which may or may not be, and so many also which are truly ecological but which do not pass under that name, that it is necessary that the student shall be able to see through its diverse guises and recognize its essential character. Whenever the question arises as to the ecological character of a fact, inference, or conclusion, its ecological validity may be tested in the following way:

Do the facts, inferences, or conclusions show a response to the inorganic or organic environment:

1. As an individual of a species or kind of animal?

2. As a group of taxonomically related animals?

3. As an association of interacting animals?

REFERENCES ON THE ECOLOGICAL STANDPOINT

In this I have listed only those papers which have seemed to me particularly significant because of their point of view, regardless of whether or not they are primarily zoölogical or specifically mention ecology.

BROOKS, W. K.