Ecological world

Physical fitness is a popular topic today. and its popularity has been a major factor in motivating college students to pursue careers in physical edu-cation, physiology of exercise, health education, nutrition, physical therapy, and medicine. The Public Health Service listed "physical fitness and exercise- as one of fifteen areas of concern related to improving the country's overall health (N).  While this might appear to be an unprecedented event. similar interests and concerns about physical fit-ness existed in this country over one hundred years ago. Between the Civil War and the First World War (WW 1), physical education was primarily concerned with the development and maintenance of fitness, and many of the leaders in physical education were trained in medicine For example, Dr. Dudley Sargent, hired by Harvard University in 1879, set up a physical training program with individual exercise prescriptions to improve a person's structure and function to achieve &q

T housands of chemical reactions occur throughout the body during each minute of the day. Collec-tively, these reactions are called metabolism. Metab-olism includes chemical pathways that result in the synthesis of molecules (anabolic reactions) as well as the breakdown of molecules (catabolic reactions). Since energy is required by all cells, it is not sur-prising that cells possess chemical pathways that are capable of converting foodstuffs (i.e., fats, proteins, carbohydrates) into a biologically usable form of energy .  This metabolic process is termed bioenergetics. In order for you to run, jump, or swim, skeletal muscle cells must be able to continuously extract energy from food nutrients. In fact, the inability to transform energy contained in foodstuffs into usable biological energy would limit performance in endurance activities. The explanation for this is simple. To continue to contract, muscle cells must have a continuous source of energy. When energy is not rea

W e find it ironic that so much effort and so many resources are put into the exploration of outer space, at a time when humans are progressively using resources to depletion and when so little is known about the biological diversity of the earth. Why is there all this publicity about ancient life discovered on the planet Mars when there are regions of the Earth where life has yet to be explored? Life at the extremes of environmental conditions are to be found on the Earth. For example, studies of life atgreat depths in the oceans has hardly begun. Recently, an entire new kingdom of deep organisms, the Archaea, has been recognised; although discovered some decades ago, genetic analysis has shown them to be quite unlike any other kind of life (Earle, 1996). We have been concerned to read of proposals for using deep oceans for disposal of global  waste that is inert or rich in metals or even in organic compounds (but not industrial organic compounds). Quite rightly, some prop

      H ow often have you seen those wonderful advertisements inviting you to have a holiday on a tropical island ( Fig. )What is it about islands, whether in the tropics or polar regions, that suggests romance, excitement and adventure? Is it because of a sense of escape from the pressures and stress of a bustling way of life, or the opportunity to savour sun-soaked beaches, or the adventure of rocky unexplored shores, or perhaps the chance of seeing unique island wildlife? It is for all these reasons that there is a growing tourist industry for many islands around the world. The wildlife of islands, especially oceanic islands , has long been of special significance in biology , ecology , conservation and biogeography. Studies of island species have also been of historical significance for evolutionary biology. Many of the world's islands have high levels of endemic flora and fauna; that is, taxa found only on a particular island and no other place.  Island biota has o

    B iogeography has had a very important role to play in the development of our understanding of biology. For example it was biogeography that was the key to developing the theory of the evolution of life.  Today, not only does biogeographical research have important applications in a world of rapidly increasing human population densities and diminishing resources, it has crucial applications for conservation and sustainable use of many levels of biological diversity. If we are to make the best uses of limited resources for conservation we must know much more about the geography and ecology of the many kinds of biological diversity. Some questions in biogeography may seem rather academic.  For example, why are certain species and certain groups of organisms foundinrid scale? localities and nowhere else? What has caused these patterns on a world Why is it that for many groups of organisms there are fewer and fewer species in the north and in the south compared to the tropic

E cology and biogeography  In 1870, the German biologist Ernst Haeckel (1834-1919) first coined the term 'ecology' and defined it as 'the total relations of the animal both to its inorganic and organic environment'. In some ways that encapsulated what ecology is today; the study of the interactions between organisms and their environment; but also including (1) the study of the abundance of organisms in space and time and (2) the processes in biological communities. Early in the 20th century, ecology emerged from natural history and wildlife manage-ment as a science.  Developments in early ecology occurred simultaneously in both North America and Europe. Landmarks in early animal ecology text-books included Arthur Pearse's Animal Ecology (published by McGraw-Hill in 1926) and the work of Charles Elton (Animal Ecology, published by Sidgwick & Jackson in 1927).  Much of the stimulus for the emergence of plant community studies came from the work of Tansle

T here are approximately million named species of living oganisms. The total number of living species is of course not known and we can only estimate what the figure might be. Estimates range from about 11 to 30 million or more. What is certain is that human impacts are causing species to become extinct faster than they can be named. Also of concern is our lack of knowledge about the named species. Scientists have intensively investigated only 10 per cent of plant species and a far smaller proportion of animal species (information from the World Commission in Environment and Develop-ment 198- publication Our common Future, Oxford University Press).  There are many terms used to refer to different groups of animals, plants and other kinds of living organism such as fungi, bacteria and viruses. The classification of biota (living organisms) has been reviewed and changed many times as a result of new information. In 1969, R. H. Whittaker of Cornell University suggested fiv