Biome

“ Countless thousands of species of animals and plants, as perfectly recognizable as those which you meet with in museums at the present day, or as the shells and remains which you pick up upon the beach—countless thousands of species of these creatures have been imbedded in the sand or mud, or limestone, just as they are being imbedded now. They furnish us with a record, the general nature of which cannot be subject to any misinterpretation, as to the kind of things that have lived upon the surface of the earth during the time that is registered by this great thickness of stratified rock. ”

“ On the oak-tree yonder, how many leaves are doing the same? Just now we felt the vastness of the earth—its extended majesty, bearing mountain, forest, and sea. Not a blade of grass but has its insect, not a leaf; the very air as it softly woos the cheek bears with it living germs, and upon all those mountains, within those forests, and in every drop of those oceans, life in some shape moves and stirs. Nay, the very solid earth itself, the very chalk and clay and stone and rock has been built up by once living organisms. ”

“ But whatever may have been the special features of its scenery, there can be no doubt of the land's existence. The carbonized plants stand up to tell us of its strange and luxuriant vegetation. We have listened to their story, and suffered them to lead us away into forest, and lake, and sea, to look on the various forms of life, vegetable and animal, which abounded in that far-distant age. ”

“ A geological formation is the sum of all the strata deposited over the whole surface of the earth during one of these epochs: a geological fauna or flora is the sum of all the species of animals or plants which occupied the whole surface of the globe, during one of these epochs. ”

“ What is said of the dissemination of fish, shells, and reptiles may be consistently said of vegetation.
The earth is filled with the seed of every plant and tree and shrub that ever sprang into life in any place, clime or time. Dig to whatever depth [76] you will, the substance you throw out, whether earth or stone, when exposed to the air, will produce some growth of vegetation. Frequently something entirely new and different from the surrounding vegetation. ”

“ An oak growing in the ocean and a seaweed on the top of a hill, are incredible combinations of ideas. We find that each kind of animal is limited to a certain range of climate; each kind of plant to certain zones of latitude and elevation. Of the marine flora and fauna, each species is found only between such and such depths. Some blind creatures flourish in dark caves ”

“ But the study of geology opens to us the spectacle of many groups of species which have, in the course of the earth's history, succeeded each other at vast intervals of time; one set of animals and plants disappearing, as it would seem, from the face of our planet, and others, which did not before exist, becoming the only occupants of the globe. ”

“ There are other governing conditions, of course, such as the average rain-fall, distance from the equator, the elevation above the sea level in the various mountain systems of vegetation, etc., including the hygrometric, thermometric, telluric, and other conditions, of the several localities in which the different species of vegetation make their appearance.
But why should this distinguished naturalist insist upon the specific creation of either plants or animals? No scientific work of any paramount value confines the creative power of the universe to such narrow and restricted limits. ”

“ Possibly nature means something by making changes of structure come about gradually with changes of surroundings. But we are here to study a work of man as helping nature. All the land that we see from this mountain top, and thousands of miles that we cannot see, lay for thousands of years a pestivorous swamp. Here and there was a deep lagoon, and here and there a patch of tropical forest. Reptiles, wading birds, deadly snakes, were the principal inhabitants of this vast area. ”

“ Warm, dank, low-lying lands, bathed by warm oceans and steeped in their vapours, are the picture suggested—as we shall see more closely—to the minds of all geologists. In those happy conditions the primitive life of the earth erupts into an abundance and variety that are fitly illustrated in the well-preserved vegetation of the forest. ”

“ It appears, therefore, that we must look upon the existence of man and many races of animals which, more strictly than he, are appointed to live under particular physical conditions, as characteristic of the last of several great periods of geological time, each marked by the creation of peculiar races of plants on the land and animals in the sea. ”

“ Physical Geology is full of such selections—of the picking out of the soft from the hard, of the soluble from the insoluble, of the fusible from the infusible, by natural agencies to which we are certainly not in the habit of ascribing consciousness.
But that which wind and sea are to a sandy beach, the sum of influences, which we term the "conditions of existence," is to living organisms. The weak are sifted out from the strong. ”

“ In treating of environment we learned that during the geologic ages of the globe, the physical geography and climate have repeatedly changed. A very cold temperature, a mountain chain, a body of water, a stretch of desert land, may completely prevent interbreeding, on either side of the barrier, between the individuals of a species. ”

“ Our earth, we find, by the records preserved in the foundation-stones of her mountains, has existed through countless ages, and through them all exhibited the same active energies that prevail at the present moment. By precisely similar influences to those now in operation, have rocks been formed, which, under like agencies, have been covered with vegetation, and sported over by, to us, strange varieties of animal life. Every plant that has grown upon the earliest rocks which presented their faces to the life-giving sun, has had its influence on the subsequent changes of our planet. ”

“ The connexion between climate and vegetation has also been studied. Quite recently under the name of “Ecology” or “Oecology” the study of plants in relation to each other and to their environment has become the subject of systematic investigation.
The subject of palaeontological botany (see Palaeobotany) has been advanced by the researches of both botanists and geologists. The nature of the climate at different epochs of the earth’s history has also been determined from the character of the flora. ”

“ The land was barren, its lakes unfitted to support life. On the other hand, it is equally likely that the first beginnings of life may have been the simple plants growing in inland waters and gradually spreading down to the sea. We do not know, but it is most probable that life began in some great body of water, where plants and insignificant animals grew together, perhaps fought together, -205- and certainly in this environment became more and more fitted for the business of living. ”

“ And again, "As geologists, we learn that it is not only the present condition of the globe which has been suited to the accommodation of myriads of living creatures, but that many former states also have been adapted to the organisation and habits of prior races of beings. The disposition of the seas, continents and islands, and the climates, have varied; the species likewise have been changed; and yet they have all been so modelled, on types analogous to those of existing plants and animals, as to indicate, throughout, a perfect harmony of design and unity of purpose. ”

“ From the point where the geological formations approach the present time, plant and animal geography also assists geology in increasing the weight of the reasons for an origin of organisms through descent. With the tertiary period, the fauna and flora of the globe, which in former periods had a nearly uniform character all over the earth and showed no climatic differences, begin to separate according to climate, zones, and greater continents. ”

“ We have seen still further that the surface of the Land, and the Waters of the Sea have during long periods, and at distant intervals of time, preceding the Creation of our species, been peopled with many different races of Vegetables and Animals, supplying the place of other races that had gone before them; and in all these phenomena, considered singly, we have found evidence of Method and Design. ”

“ Fossil remains show that regions far north, now covered with perpetual ice, once supported a luxuriant flora and fauna, and many regions in the temperate and equatorial zones that are now deserts were once overgrown with forests and teeming with animal life. The fundamental thing of the cosmos is change—birth, growth, maturity ”

“ And now we near the vast Carboniferous continent, and see along the undulating outline, between us and the sky, the strange forms of a vegetation, compared with which that of every previously seen land seems stunted and poor. ”

“ Lastly, the terrestrial flora became most diversified and most perfect when the highest orders of animals, the mammalia and birds, were called into existence.
Now in the first place, it may be observed, that many naturalists are guilty of no small inconsistency in endeavoring to connect the phenomena of the earliest vegetation with a nascent condition of organic life, and at the same time to deduce from the numerical predominance of certain forms, the greater heat or uniformity of the ancient climate. ”

“ To examine these vestiges in strata superposed as by steps, one above another, is to study the Fauna of different ages and to compare them together. The geography of animals marks out limits in space, according to the diversity of climates, which determine the actual state of vegetation on our planet. The geology of organized bodies, on the contrary, is a fragment of the history of nature, taking the word history in its proper acceptation: it describes the inhabitants of the earth according to succession of time. ”

“ The central thought of each step in the Scripture cosmogony—for example, Light,—the dividing of the fluid earth from the fluid around it, individualizing the earth,—the arrangement of its land and water,—vegetation,—and so on—is brought out in the simple and natural style of a sublime intellect, wise for its times, but unversed in the depths of science which the future was to reveal. The idea of vegetation to such a one would be vegetation as he knew it ”

“ The physical description of the globe teaches us that vegetation every where presents numerically constant relations in the development of its forms and types; that in the same climates, the species which are wanting in one country are replaced in a neighboring one by other species of the same family ”

“ We might have expected that the flora of a mountain summit would have presented the same relation to the flora of the surrounding lowland country, which any isolated part of a continent does to the whole, or an island does to the mainland, from which it is separated by a rather wide space of sea. ”

“ The habitat is the sum of all the forces or factors present in a given area. It is the exact equivalent of the term environment, though the latter is commonly used in a more general sense. As an ecological concept, the habitat refers to an area much more definite in character, and more sharply limited in extent than the habitat of species as indicated in the manuals. Since the careful study of habitats has scarcely begun, it is impossible to recognize and delimit them in an absolute sense. ”

“ What we propose, in short, is to give a history of the formation of the globe, and a description of the principal rocks which actually compose it; and to take also a rapid glance at the several generations of animals and plants which have succeeded and replaced each other on the earth, from the very beginning of organic life up to the time of man’s appearance. ”

“ To understand rightly the daily accumulating stores of organic reliquiæ, requires more than a slight knowledge of existing nature,—more even than an acquaintance with animal and vegetable forms. The philosophy of their existence must be considered—the variations of their structure, with respiration in air or in water—life in fresh or salt water—in trees or on the ground—carnivorous or herbivorous food—their geographical distribution dependence—on climate and atmospheric conditions. ”

“ Vegetation of all sorts acts in a similar way, either in forming soil and assisting in breaking up rocks, in filling up shallow lakes, and even, like the mangrove, in reclaiming wide stretches of land from the sea. Plant life, utilizing solar light to combine the inorganic elements of water, soil and air into living substance, is the basis of all animal life. ”

“ We meet as we go back in time with constant alternations of sea and land, of estuary and open ocean, and in correspondence with these alternations we meet with changes in the fauna and flora of the kind I have stated. ”

“ Except where the surface of the ground has been artificially sterilised by man, or is rendered unproductive by ice, by lava, by a total lack of water, or by the existence of poisonous salts, it is clothed with vegetation, and it is the presence of this vegetation which is its most obvious character. ”

“ Variation and natural selection would also afford a key to a multitude of geological facts otherwise wholly unaccounted for, as, for example, why there is generally an intimate connection between the living animals and plants of each great division of the globe and the extinct fauna and flora of the post-tertiary or tertiary formations of the same region ”

“ Instead of its being part of the plan of nature to store up enduring records of a large number of the individual plants and animals which have lived on the surface, it seems to be her chief care to provide the means of disencumbering the habitable areas lying above and below the waters of those myriads of solid skeletons of animals, and those massive trunks of trees, which would otherwise soon choke up every river, and fill every valley. ”