For the most part in this website we have based our approach to ecology on the analysis of units of the landscape as ecological systems. Principles and common denominators that apply to any and all situations, whether aquatic or terrestrial, natural or man – made, have been emphasized. The importance of the driving force of energy has been stressed. In this post useful approach was introduced, that of concentrating study on population units which are the vehicles for evolutionary change. Still another useful approach is geographical – involving the study of the pattern of earth forms, climates, and biotic communities that make up the biosphere. In this post we shall list and briefly characterize the major ecological formations, or easily recognized ecosystem types, with emphasis on geographical and biological differences that underlie the remarkable diversity of life on earth. In this manner we hope to establish a global frame of reference for the next and this post, which deals with mankind’s new challenge to attack his problems on a large scale.

       We would do well to start our world tour with the seas, the largest and most stable ecosystem. The sea, presumably, was the first ecosystem, for life is now thought to have originated in the saltwater nileu.

       The energy resource situation in the united states, as well as in all of the other industrialized nations and most of the undeveloped ones can be very simply and bluntly stated as follows; energy use is, or will very soon be, greater than that which can be supplied at a reasonable cost form source within the boundaries of the nation. Which is to say that even where there are large reserves such as coal, oil shale, or offshore oil, the high cost of procurement and conversion will place severe constraints on economic growth and create difficult balance of trade problems for individual nations. Undeveloped countries that lack fuel resources ae particularly hard hit when the rice of fuel rises. The need to conserve energy (by reducing waste and increasing the efficiency of use), to allocate supplies on a worldwide basis, to increase efficiency of conversion of ‘’difficult to get at’’ sources, and to seek new sources will all receive the undivided attention of mankind for a long time into the future. This is a prime example of the long range problem that cannot be solved on a crisis basis.

         It is vitally important that everyone study carefully and strive to understand the nature of atomic energy, about which there is so much hope and controversy. It is especially important to distinguish between to several types of nuclear power. The kind of atomic energy now being used to generate electricity on a limited scale is based on the fission or ‘’splitting’’ of the uranium with the release of energy, and also the release of dangerous ‘’fission products’’ such as radioactive strontium and cesium. Some plutonium, an extremely dangerous radioactive substance (and, also, one that can be made into bombs), is also a by product. Fission atomic energy is a ‘’fuel’’ energy since the supply of fissionable uranium (²³⁵U) is limited); actually there is less energy in this form than in coal left in the earth’s crust. Also, tapping this source of energy is proving to be more troublesome and expensive than originally predicted. The breeder reactor now undergoing experimental test would rolong the uranium fuel supply since a more abundant from of uranium (²³⁵U) can be used and new fissionable fuel is created in the reactor as the original fuel is used up. But an increased production of plutonium increases the radiation hazard.

         Nuclear fusion is a different form of atomic energy entirely, one that involves the fusion of light atoms such as hydrogen to form a heavier atom with the release of energy. Extremely high temperatures are necessary for this energy release which resembles that which occurs on the sun. fission products and plutonium would not be produced unless a fission reaction were to create the temperatures necessary for fusion (as in the hydrogen bomb), but there would be problems with radioactive hydrogen (tritium). Controlling fusion involves containing the intense reaction, perhaps within magnetic fluxes or with laser beams, since no vessel could stand the temperature required. There is much discussion about hybrid fission – fusion systems, but any widespread use of fusion as a worldwide source of industrial energy is a long way in the future. Recent issues (1972, 1973, and so on) of science and public affairs: bulletin of the atomic scientists contain many informative and largely nontechnical articles on nuclear energy. For a nontechnical book, see Inglis (1973).

        We have already discussed in some detail solar energy (see this post). This abundant, but dilute and low quality energy resource can be put to work in cities doing low level ‘’jobs’’ such as heating water, commercial buildings, and dwellings thus sparing fuel for other uses. Extensive use of solar energy in the place of fuel requires a technology not yet developed. Direct conversion of sunlight into electricity by means of solar cells is a promising new technology now under intensive study. Another way we could upgrade solar energy for higher level work would be to make use of nature’s efficient conversion, namely photosynthesis, for fuel as well as for food. Szego (1973) has calculated that the annual growth of wood in managed ‘’fuel forests’’ could supply the united states with substantial amounts of electricity if burned in wood fired, steam electric plants. The long term cost benefit of such a use is yet to be calculated but it is a possibility worth considering in regions where forests are climax, human population density low, or where there is a lot of hilly land not suitable for agriculture

or other man forest uses.

         The ‘’food for man’’situation was discussed in detail in this post reemphasizes the key role that energy subsidies play in the production of food and fiber (cotton, wool, paper, wood, and so on). The age old paddy rice culture is very efficient in terms of food yield per unit of energy subsidy, but it is backbreaking for the people who plant and harvest the rice. At the other extreme, feedlot beef requires 10 cal of fuel energy for every calorie of food produced, but neither man nor beast has to do much work. Feedlots do not make very good ecological sense for another reason. Cows have a marvelous adaptation the rumen, which enables them to convert very low protein food such as grass and hay into high protein food. When cows are fed rich grains in a feedlot, this adaptation is bypassed, and the meat produced tends to be too fatty for good human health. Also, feedlots produce server watershed pollution that adds another stress on the environment, and another cost for man. There is much to be said for putting the cow back on grass.

        Avoidance of the boom and bust syndrome, as discussed on this post is another reason for considering a somewhat Les energy intensive agriculture especially for undeveloped countries. It is difficult and costly in terms of energy to sustain very high yields of the same crop over long periods of time.

          Human civilization seems to reach the most intense development in what was originally forest and grassland especially in temperate regions. Consequently, most temperate forests and grasslands have been greatly modified from their primeval condition, but the basic nature of these ecosystems has by no means been changed. Man, in fact, tends to combine features of both grasslands and forests into a habitat for himself that might be called forest edge. When man settles in grassland regions he plants tree around his homes, towns, and farms, so that small patches of forest become dispersed in what may have been treeless country. Likewise, when man settles in the forest he replaces most of it with grasslands and croplands (since little human food can be obtained from a forest), but leaves patches of the original forest on farms and around residential areas. Many of the smaller plants and animals originally found in both forest and grassland are able to adapt and thrive in close association with man and his domestic or cultivated species. The American robin, for example, once a bird of the forest, has become so well adapted to the man – made forest edge that it has not only increased in numbers but has also extended its geographical range. Most forest birds in Europe have ditches from the forest to gardens, cities, and hedgerows or else they have become extinct, since there are no longer many large tracts of unbroken forest. Most native species that persist in regions heavily settled by man become useful members of the forest – edge ecosystem of man, but a few become pests. The worst pests, however, are more likely to be species introduced from afar, as was discussed in that’s post.

        If wee consider croplands and pastures as modified grassland of early succession types, then man depends on grasslands for food, but likes to live and play in the shelter of the forest, from which he also farmers useful wood products. At the risk of oversimplifying the situation we might say that man in common with other tropospheres seeks two basic things from the landscape; ‘’production’’ and ‘’protection’’ but unlike lower organisms, he also finds aesthetic enjoyment in the beauty of natural landscapes. For mankind, forests provide all three needs, but especially the latte two. In many cases the monetary value of the wood, if harvested all at once, is far less than the value of the intact forest that provides recreation, watershed protection, home sites, and so on, plus a modest harvest of wood as well.