It is obligatory to learn Ecology (Gr. oikos = home, logos=science) – the branch of biology concerned the relationship between an organism or a group of organisms and other living things and with their environment (organisms = biotic components and abiotic factors or conditions = inorganic or organic matter, climate). The concept and name “ecology” were introduced by Ernst Haeckel (1866). Defining the ecology now we should emphasize the influence of the organisms on their environment. It is especially important from the view point of a modern man, who is not only an element of the biosphere, but also is changes the biosphere. The environment in the definition means a part of surrounding conditions having influence over natality and surviving of the organisms. Human ecology is an interdisciplinary science. It is interested in dynamic biological and social processes between men (individuals, populations and societies) and their environment – natural (biosphere), social (sociosphere), technical (technosphere) and also cultural (noosphere). Medical ecology is a part of human ecology. It concerns pathogenic influence of environmental factors or conditions in broad mind (biosphere, technosphere, sociosphere, noosphere) on human populations and also with the health effects of the environment degradation. Basic terms of ecology: Biosphere – the zone of the earth in which living things are found, also the global ecosystem, the sum of all ecosystems. Population – a collection of individuals of the same species, living in a geographic area, in the same region. Biocenosis (= community) – a collection of populations living together in specific region, in an abiotic environment (called biotope).Components of the community (biotic components) include producers (autotrophs), consumers (heterotrophs – herbivores, carnivores, omnivores) and decomposers (heterotrophs – saprophages, saprophytes, detritiovores, decomposers, scavengers) forming food chains. Ecosystem – a functional ecological unit composed of biocenosis and the environment (biotope); a dynamic and complex whole not fully isolated from surrounding units but interacting; functional unit in equilibrium (homeostasis), characterized by energy flow and matter circulation. Ontocenosis – a collection of organisms living together in organs of human organism. Consumers III organic matter Consumers II Consumers I CO2 Decomposer Producers s CO2 sunlight Fig. Diagram of energy flow in ecosystem. Energy flow through ecosystems: - photosynthesis – capture of sunlight energy, using water and carbon dioxide and producing oxygen and carbohydrates; only 2% of sunlight energy is available for producers; - respiration – splitting carbon and hydrogen from carbohydrate and recombining them to release energy and produce carbon dioxide and water; - every transfer of energy results in less useful energy available; - energy is neither lost nor gained; - kinds of energy: chemical, mechanical, thermal. Succession (ecosystem development and change over time): - a directional and predictable process of community development that involves changes in species composition and community processes with time; the sequence of communities that replace one another during succession, each is called a seral stage of succession; early seral stages are pioneer stages, while the final seral stage is called the climax community; - results from modification of the physical environment by the community itself; the populations tend to modify the physical environment, making conditions favorable for other species; -culminates in a stable ecosystem in which biomass and symbiotic relationships are maximized per unit of energy flow; as succession proceeds from early seral stages towards the climax, energy flow tends to shift from productivity (in early stages) to maintenance (in later stages). Primary succession occurs on an area that has not previously been occupied by a biotic community (such as newly exposed rock surface or volcanic island). It tends to proceed more slowly. Secondary succession occurs in an area from which a biotic community was removed (such as when a forest is clear cut). It tends to proceed more rapidly. The natural ecosystems, affected by humans, are changed and destroyed, devastated. The development of human culture (“industrial revolutions”) has brought us to our current stage of environment exploitation. Ecological interactions could be divided on infraspecies and interspecies interactions. (0) indicates no significant effect on one species population; (+ ) indicates positive effect on one species population; ( - ) ) indicates negative effect on one species population. Neutralism ( 0 , 0 ) - neither population affects the other. The antagonistic interactions Competition ( - , - ) - between members of the same species for food, nesting materials, mates etc, - between members of two or more species for resources (sunlight, food, habitat, etc) Antibiosis ( 0 , - ) - one population affects the other by own metabolites, causing death or stopping growth of the other population (e.g. fungi producing antibiotics and bacteria, plants producing volatile oils and microorganisms) Penicillin was the first discovered antibiotic. In 1929 Fleming noted that bacteria colonies (Staphyllococcus aureus) around the fungus colonies (Penicillium notatum) were lysed. Fungal metabolite, that may be used to control bacteria, was named penicillin. Later other antibiotics produced by microorganisms were found, e.g. streptomycin, produced by Streptomyces griseus. Now the list of antibiotics used in medicine is long. They are useful in bacterial and fungal infections. The problem is the development of antibiotic resistance in bacterial cells. Parasitism ( + , - ) - one population (usually the smaller organism) adversely affects the other, but requires the other population for its survival; Parasite is an organism which exploit another organism (host) as a source of food and often always as a surrounding of life, doing detriment to the hosts organism. The parasite does not kill its host. Parasites can attack their hosts only in order to gain food (for instance biting insects), or they live in the body of their host (or hosts) all his life (e.g. Plasmodium). The organ in which parasite lives is called ontohabitat. Predation ( + , - ) - one population (the predators, usually the larger organisms) is feeding on others (the preys) but requires the other population for its survival; The relationship between the predator and prey are slowly evolving mechanisms that maintain stable population levels. An increase in prey population allows increase in predator population, which acts as negative feedback, decreasing prey population. The curves of the relationship between the number of predator and victim show that the increase in the number of victim always precedes the increase in the number of predators. The protectionist interactions Commensalism ( 0 , + ) - one population benefits from association but the other population is unaffected; Most of these interactions are facultative. From the medical point of view, the important one is the occurrence of opportunistic fungi, which normally live in various organs of our organism, and sometimes become pathogenic. Phoresis ( 0 , + ) - a fairy loose association in which one organism, usually smaller that the other, uses the larger organism as a transport host (e.g. flies and bacteria). Mutualism ( + , + ) - both populations benefit from the mutual association; These interactions are frequently very intimate and obligatory. Both partners derive benefits. For instance lichen, which is composed of fungus and alga. In our intestine the bacteria Escherichia coli, are very beneficial to us, because of vitamins B12, C and K production. The Biosphere The term "Biosphere" was coined by Russian scientist Vladimir Vernadsky in 1929. The biosphere is the life zone of the Earth and includes all living organisms, including man, and all organic matter that has not been decomposed yet. Life evolved on earth during its early history between 4.5 and 3.8 billion years ago and the biosphere readily distinguishes our planet from all others in the solar system. The chemical reactions of life (e.g., photosynthesis- respiration, carbonate precipitation, etc.) have also imparted a strong signal on the chemical composition of the atmosphere, transforming the atmosphere from reducing conditions to and oxidizing environment with free oxygen. The biosphere can be divided into distinct ecosystems that represent the interactions between a group of organisms forming a trophic pyramid and the environment or habitat in which they live. The biosphere includes: aerosphere, hydrosphere, lithosphere and antroposphere. Aerosphere The atmosphere is the gaseous envelope that surrounds the Earth and constitutes the transition between its surface and the vacuum of space. The atmosphere consists of a mixture of gases composed primarily of nitrogen, oxygen, carbon dioxide, and water vapor. It extends some 500 km above the surface of the Earth and the lower level (troposphere) constitutes the climate system that maintains the conditions suitable for life on the planet's surface. The next atmospheric level, the stratosphere (12 to 48 km), contains the ozone layer that protects life on the planet by filtering harmful ultraviolet radiation from the Sun. The aerosphere contains the lower level of atmosphere (troposphere) and a part of stratosphere (to 22 km). Since the Industrial Revolution, man has been altering the composition of the atmosphere by burning fossil fuels. There is growing concern about rise in concentrations of carbon dioxide, methane, nitrous oxide, and chloroflurocarbons in the atmosphere because these "greenhouse" gases trap heat energy emitted from the earth surface and increase global temperatures (global warming). In addition, chloroflurocarbons cause depletion of the Earth's ozone shield that protects the Earth surface from the harmful effects of ultraviolet radiation. Hydrosphere The hydrosphere includes all water on Earth. In one respect, the planet Earth is a misnomer in that 71% of the earth is covered by water and only 29% is terra firma. Indeed, the abundance of water on earth is a unique feature that clearly distinguishes our "Blue Planet" from others in the solar system. Not a drop of liquid water can be found anywhere else in the solar system. It is because the Earth has just the right mass, the right chemical composition, the right atmosphere, and is in the right distance from the Sun (the "Goldilocks" principle) that permits water to exist mainly as a liquid. However, the range of surface temperatures and pressures of our planet permit water to exist in all three states: solid (ice), liquid (water), and gas (water vapor). Most of the water is contained in the oceans and the high heat capacity of this large volume of water (1.35 million cubic kilometers) buffers the Earth surface from large temperature changes such as those observed on the moon. Water is an universal solvent and the basis of all life on our Planet. Links to other components: Water cycles between the various components of the Earth system via the hydrologic cycle. Aerosphere: Water is transferred between the hydrosphere and biosphere by evaporation and precipitation. Energy is also exchanged in this process. Biosphere: Terrestrial plants withdraw water from the ground using their root systems and transport water and nutrients through the vascular system to stems and leaves. Evaporation of water from the leaf surface (called transpiration) is effective at transferring water to the atmosphere. Lithosphere: Water is the primary agent for the chemical and mechanical breakdown of rock, called weathering, to form loose rock fragments (regolith) and soil. By the process of erosion, water sculpts the surface of the Earth as precipitation that falls on the land making it way by to the sea. Lithosphere The lithosphere is the solid Earth that includes continental and oceanic crust as well as the various layers of the Earth's interior. The lithosphear as a part of biosphear contain some hundred meters of the Earth's interior and exterior part of the Earth. Ninety-four percent of the earth is composed of the elements oxygen, iron, silica, and magnesium, and the interior of the earth is layered both chemically and mechanically. The lithosphere is not static, but its surface (crust) is in a constant state of motion that gives rise to movement of the continents. The impact of human activities with negative influence on environment. Throughout history, the world’s population has expanded. Massive and still increasing population, combined with the environmentally detrimental repercussions of industrialization has begun to take a serious toll on our planet’s ecosystem. Overpopulation, in conjunction with industrialization on a global scale, has led to continuingly deteriorating environmental conditions. Such expansion has begun to affect the environment in many ways. Human Impacts –The Aerosphere. The Enhanced Greenhouse Effect or Global Warming. This process occurs mainly due to human industrialization. The excess Carbon Dioxide and other greenhouse gases (methane and freons) being released into the atmosphere trap retain the sun’s heat, reflecting it back to Earth. As a result, the Earth’s average temperature is gradually rising. Studies have shown that the Earth has warmed an approximate 0.5 Celsius degrees over the past 100 years. This number is estimated to rise to 3 degrees before the end of this century. Although this number may seem relatively small, this temperature increase can cause significant changes in the climate across the globe, affecting various forms of life. Some scientists speculate that Global Warming may lead to droughts, excessive heat waves, forest fires, violent storms and famines. Melting of the icecaps is another concern. Major costal cities across the globe can be flooded, or completely submerged. Many animals that live in Arctic habitats will also be lost forever. With warmer temperatures, comes more disease or heat related problems, appear such as heat stroke. These and many other examples demonstrate the severity of Global Warming. Although this topic is a deep concern for environmentalists many believe that there is no need to panic. The Greenhouse Effect is a gradual process, allowing time for research on how to approach this problem. Ozone Depletion refers to the loss of stratospheric ozone due to the presence of CFC’s (chlorofluorocarbons – mainly freons) and some carbohydrates (metan). Ozone is broken down naturally in the stratosphere by sunlight and chemical reactions with compounds containing nitrogen, hydrogen, and chlorine. In a normal atmosphere the ratio of ozone being created to ozone breaking down remains fairly constant. The greatest amount of ozone is found at an altitude of twenty-five kilometers and is known as the ozone layer. Ozone's unique properties allow it to act as a protective layer around the Earth. It acts like a sunscreen, filtering damaging UV rays. This layer is thickest at the poles and thinnest at the equator. The depletion of ozone due to human activities occurs in the stratosphere. When chlorofluorocarbons reach the stratosphere, they break up ozone molecules. Small quantities of CFC cause significant reduction in stratospheric ozone. Stratospheric ozone, called “good” ozone, as mentioned above prevents harmful UV radiation from reaching the Earth’s surface. Excessive exposure to UVB radiation may cause skin and eye irritation, may lead to skin cancer, also is harmful for many plants important in agriculture. CFC were used for numerous applications (in air conditioners as coolants, for cleaning electronic circuit boards, as solvents, in the past used as a propellant in aerosol cans). Every year since the early 1980’s, a huge hole in the ozone layer opens up over Antarctica. A similar thinning occurs over the North Pole. These “holes” may be responsible for increasing rates of deadly skin cancer in recent years. Air pollution refers to any substance that degrades the quality of air. There are many natural sources of air pollution (dust, volcanoes, forest fires, etc.). However, there are natural mechanisms to reduce these pollutants (i.e. rain, wind). Anthropogenic (human caused) air pollution is a problem because substances are emitted into the air faster than the natural mechanisms can eliminate them. As a result these substances accumulate. Anthropogenic pollution contains many synthetic substances very toxic because they interfere with living organisms. There are often no natural mechanisms to remove them from the atmosphere. Primary Pollutants are substances emitted into the atmosphere that have a direct effect on air quality, such as Hydrocarbons (benzene, toluene, etc), carbon dioxide, etc. Secondary Pollutants are substances that are the product of primary pollutants reacting together in the atmosphere. (Nitric Oxides and Sulfur Oxides react with water to form nitric acid and sulfuric acid - form acid rain and acid fogs. In this case nitric acid and sulfuric acid are secondary pollutants). Carbon Dioxide, Carbon Monoxide, Nitric Oxides, Sulfur Oxides, Hydrocarbons and Particulates are the six important pollutants. Major source of carbon dioxide, carbon monoxide, sulfur oxides, nitric oxides, and particulates is combustion of fossil fuels. Hydrocarbons are also produced form combustion of fossil fuels, but their main source is the petrochemical industry (oil refineries, metal smelters, rolling mills, plastic factories, chemical manufacturers). Sulfur oxides and nitric oxides react in the atmosphere to produce sulfuric acid and nitric acid. The main source of both oxides is automobiles, refineries, coal power plants. Acid precipitation causes extensive damage to both terrestrial and aquatic ecosystems. Acidified streams and lakes undergo marked changes in vegetation, invertebrate populations, and fish populations. Hydrocarbons (Volatile Organic Compounds) In chemistry, any carbon-containing compound is referred to as organic. However, these substances can be extremely toxic (e.g. PCB’s, dioxins, benzene, acetone, formaldehyde, etc.) can be carcinogens – cause cancer. They may act as mutagens – cause mutation, or as teratogens – cause birth defects. There are literally thousands of toxic organic compounds produced by various industries. People living in areas near chemical plants often have much higher risk of cancer and birth defects (so-called "cancer clusters"). Particulates are small particles emitted into the air. Anthropogenic particulates often contain heavy metals (e.g. lead, mercury, cadmium, arsenic, selenium). These substances accumulate in tissues. In addition, many particulates are respiratory irritants and can cause or increase the effects of bronchitis and asthma. Particulates are especially prevalent in urban areas and in industrial areas. Ozone is a secondary pollutant when it appears near the ground (tropospheric ozone) - it is a severe respiratory irritant – therefore tropospheric ozone is often referred to as the “bad” ozone. Tropospheric ozone is a product of mixing of nitric oxides, hydrocarbons, and oxygen in the presence of heat and sunlight. Conditions that favor ozone production are hot, sunny days, when there is little or no wind. Ozone is also a component of urban smog and can cause eye, nose, and respiratory problems in both humans and animals. Human Impacts – The Hydrosphere. Any substance that degrades the quality of water causes water pollution. Many of these pollutants are similar to the ones found in air pollution. However, water pollution is much more complicated because we have so many different uses for water and, therefore, there are many ways that water pollution can affect us. Organic Chemicals come mainly from agricultural sources and industries. Most dangerous are carbon containing molecules – pesticides, PCB, dioxins, solvents, etc. These substances are directly toxic to humans and wildlife, thus causing ecosystem disruption. Also, many of these substances act as carcinogens, teratogens, or lower fertility. Dead Organic Matter comes from sewage, urban garbage, agriculture. It consists of carcasses, plant and animal wastes, raw sewage and leads to high biological oxygen demand (BOD). This disrupts aquatic ecosystems, eliminates oxygen dependant species (like fish). Pathogens come from raw sewage and human wastes (also medical wastes) Pathogens are the microorganisms or their byproducts which cause human diseases (cholera, typhoid, dysentery, giardiosis, etc). Nutrients come mostly from agricultural sources (nitrogen and phosphorous – used to fertilize crops). Nutrients cause “algal blooms” in aquatic systems. The end result is the loss of all oxygen dependant species. Heavy Metals come from agriculture, industries, and urban run-off. Heavy metals like mercury, selenium, cadmium, lead, and chromium have direct toxic effects and therefore lead to ecosystem damage and human health problems. Acids mostly from industrial and domestic sources are directly toxic to many organisms Some industries dump strong acids directly into aquatic systems – this leads to ecosystem failure. Sediments come from construction sites, agriculture, forestry, and urban run-off. Sediments alter energy flow through the water and alter bottom environments. Many aquatic organisms can only live in clear waters with rocky or gravelly bottoms - sediments eliminate these species. Heat comes from industries and power plants. Excessive heat from industrial cooling water causes water to lose oxygen and eliminates any cold-water species that are present in the system. Radioactivity - main sources are industries, hospitals, and medical research facilities. Radioactive substances are extremely toxic in even very small quantities and can cause cancer and death to both humans and other organisms. Human Impacts – The Litosphere. Human negative influence on litosphere occurs mainly in its superficial layer. Soils, their living organisms, and the plant ecosystems rooted in them, have developed in close synchrony ever since plants evolved. Man's intervention, by cutting forests, seeding grassland and planting crops amounts to a major shock to earth. Man's ignorance and unfriendliness towards the soil may lead to his own destruction. It is estimated that due to man’s intervention approximately half of World’s soil deposits are degradeted. The main reasons of soil destruction are forest cutting, alkalization or acidification of soil, land desertification. Contamination of soils by lead is a major concern in many countries at the moment. It is believed that the primary cause of the increased levels found oils is car exhaust emissions. Although unleaded petrol has been available for some time now the lead particles still remain from the time when lead was added to fuel as a thinner. Agriculture is an industry, which works directly with the soil and as a result it is bound to have some effects on the make up of the soil. The use of pesticides and fertilizers causes many implications, not only for the environment and wildlife involved but it may also affect human activity such as drinking water, or leisure activities like swimming and fishing. Bioaccumulation and biomagnification of these poisons as they move along the food chain is also a major problem, which has an influence on the whole ecosystem. Human Impacts – Loss of Biodiversity Every year it is estimated that 1000 to 2000 species go extinct (3-5 species per day). At the current rate of extinction, close to ¼ of all terrestrial plants will be extinct in 50 years. There is debate over these numbers, though all scientists agree that the loss of biodiversity is an extremely serious problem. Human Impacts - Ecological Catastrophies Difficult to predict ecological catastrophies present another serious challenge for biotop. Forest fires, hurricanes, volcano eruptions, draughts or floods and earthquakes are examples of natural catastrophies. However a significant number of catastrophies is caused by human activities (industrial catastrophes, nuclear explosions, terrist assaults, toxic contamination from leaking pipes or containers, etc.). The frequency of natural catastrophies has been increasing expotentially. For example in the nineties of the 20 th Century natural catastrophies occured 5 times more frequently than in the seventies, possibly due to global warming effect. It is noteworthy, that developing countries are most affected by natural catastrophies. A number of disciplines co-operating with ecology such as catastrophe medicine, rescue medicine contribute to solve this problem. House is e very specific habitat for people. We can even indicate indoor and outdoor environmental factors. According to the studies conducted in the United States adults spend at their houses approximately 60% of a day (twenty-four hours); whereas at work and outside buildings 25% and 2%, respectively. Our house can partially protect us from an unfavorable influence of abiotic factors of biotope (temperature, moisture, solar radiation, noise, dusts and chemical pollution of air) as well as of biotic ones (predacious, poisonous and parasitic animals and also microbe-vectors, poisonous plants, pathogenic bacteria and fungi). Yet, it should be stressed that often there is an important correlation between the intensity of external abiotic factors (temperature, moisture, air-pollution with sulphur-dioxide and dusts) and indoor ones. Its flora and fauna, sometimes pathogenic, also characterize each house. In some household goods (flower-vases and other utensils, heat exchangers) as well as in hospital ones (tubes, catheters, containers) we can find living pathogenic bacteria (i.e. blue pus bacterium – Pseudomonas aeruginosa, Vibrio cholerae, staphylococcal bacteria, Klebsiella sp.) existing in the shape of so called biofilms. Particular resistance of organisms from biofilms towards some chemical factors depends not only on the protective extracellular substance produced by them and enzymes (i.e. penicillinase) but also on mutual protectionist interactions – transmission of stimuli to reproduction and microcolonies formation, feeding with useless metabolites of another species, etc. It is also important to remember that a house itself can be the source of many threats for its inmates. We should take into consideration oxidization products (carbon oxide and dioxide, nitric oxide, aromatic hydrocarbons) arising in heating-units, cookers and also during smoking tobacco. Refrigerating-units can produce volatile and semivilatile organic compounds (formaldehyde, benzene, tetrachloroethylene, chloroform, methylene chloride, trichloroethane, carbon tetrachloride, aromatic and aliphatic hydrocarbons) as well as terpens in other forms (limonene, pinen); insecticides, polichlorobiphenyles from different houdehold units, furniture, paints, clothing materials and also from food. Some poisonous substances were used in the past in paints (lead components) and in building materials (asbestos fibres). We should also remember about noxious radiation of radon, radium and uranium, which can be found in plasters, and walls of houses. Injuries of extremities, burns of surfaces of a body, intoxications are the result of mechanical and chemical damages and also electrocution. The health and comfort problems observed among building occupants are generally divided into two categories: 1. Building-associated symptoms (often called sick building syndrome) 2. Building-related illness (BRI) Building-associated symptoms are common and are generally nonspecific: discomfort problems affecting the eyes, nose and throat. There are no definitive clinical tests available to establish the diagnosis of sick building syndrome, rather building-associated symptoms are recognized by identification of indoor air quality (IAQ) environmental problems or higher combined symptom rates among a group of building occupants. In contrast, building-related illnesses are uncommon and by definition are more serious in prognosis than mere discomfort. Physician diagnosis by clinical investigation of symptoms is the usual means of recognizing building-related illnesses. Building-related illnesses can have a long latent (or asymptomatic) period after exposure begins before symptoms are experienced, such as occurs with lung cancer after indoor radon exposure. The three categories of building-related illnesses generally recognized are: 1. Toxic illness Example: carbon monoxide poisoning 2. Infectious diseases Example: Legionnaires’ disease 3. Allergic diseases Example: asthma, hay fever, hypersensitivity pneumonitis Building-related illnesses generally require a prolonged recovery time or may become a chronic problem for the particular patient, even after removal or remediation of the building exposure that caused the illness in the building. House is not only a part of biosphere and technosphere but also is a very important compound of sociosphere and noosphere. United Nations Organization (UNO) in the Declaration of Human Rights (1948) accepted the conception of “roof over one’s head” as the fundamental right of each human being. It should be emphasized that modern house should be “ecological”, it means that it can not be imminent over human environment – it has to secure protection from noxious indoor and outdoor factors; it also has to be energy-sparing, it should secure the proper management with household refuse and close relationship with human environment. Ecosystem of a modern man consists not only of technosphere’s factors but also of social conditions (sociosphere). Sociosphere contains family, neighbour, social, tribal, nationalistic and even national ties as well as the activity of public organizations, urbanization and professional factors, security issues, economic activity. We can not also ignore the significance of cultural factors (noosphere) i.e. educational and scientific activity, economical and legal opinions, achievements of computer science, role of health care, artistic creativeness, recreation, meaning of political, ethical, religious opinions, etc. All those factors make the macroecosystem of a human being of the 21st century multidimensional. Town is the specific kind of anthropogenic “ecosystem” of a civilized man. According to the UNO’s criterion we can talk of a town if it has over 20 thousand inhabitants. This particular environment is characterized by the predominance of factors associated with technosphere. It is also characterized by the specific flow of matter and energy. Within the area of a town we can notice lower intensity of solar radiation, higher mean temperature, lower moisture, weaker winds, greater cloudiness and precipitation. The environment of a town has also other specific features such as: greater intensity of noise, magnetic fields, vehicular traffic and nights’ lighting. All the above-mentioned factors can have an influence on animals’ population (changes of feeding period and reproductive cycle, degradation of unions, reduction of variety) as well as on some disturbances in plants (changes in vegetation cycle, expansion of xerophytes, occurrence of parasites, reduction of variety). Among the area of a town we can find even greater density of invertebrates and vertebrates than in natural conditions. The influence of anthropopressure is particularly intensive in the environment of a town with all unfavourable effects of this activity towards human population, animals and plants (urbicenosis). In town, the death rate of human population is usually higher than in surroundings. Tuberculosis, cardiovascular diseases due to atheromatosis, hepatic cirrhosis, lung cancer, allergic diseases and others occurs more often in town. It should be emphasized that so-called civilization-related diseases (cardiovascular and nervous system disturbances, cancers, some intoxications – occupational and drug poisoning, results of communication accidents) concern approximately 70% of urban population in Poland. Prospects of further developments in medical ecology and anthropogenic activities, favourable to biosphere, ecosystems, and human populations, seem to be prosperous. Efforts of numerous institutions and ecological organisations (in Poland the number of organisations declaring ecological objectives amounts to some 700, including the Polish League for Nature Conservation with 700 thousand members) have made so far the public aware of human and human environment ecology issues as well as have stimulated activity of competent international and national authorities. Now, on the verge between 20 th and 21st centuries, bearing in mind Goetel’s* maxim, “what technology spoiled, technology should repair” – I would also add “and science” – we can expect unbelievable achievements of technology and science. The above relates well to emerging era of nanotechnology. This technology can construct devices of 10-9 m in size, e.g. molecular “forceps” made of DNA molecule that are driven by the energy of the fissure of the molecule bonds, nanoinjector of a few nanometres in diameter enabling insertion of genes into a cell, an “engine” as small as a virus, driven by the energy of ATP and reaching the speed of 8 rpm, molecular transistors – those recently developed are 20 nm in length and have gates consisting of three-atom layers – and even a processor that will be constructed of almost 1 billion nanotransistors of switch rate of 1.51018 per second, supplied by electric tension below 1 V. Some of the devices will be able to self-replicate. There are designed nanorobots for rapid diagnostic tests, performing some special surgical operations, delivering drugs inside the patient organism into unreachable so far areas, according to a prescribed programme, nanodevices removing impurities at molecular level and destroying viruses and bacteria or neoplastic cells. Generally, atom represents the limit of nanostructures as a creation of smaller structures would require elemental transformation. So-called quantum dots (crystals of some hundreds atoms) attached to particles of medical significance enable tracing their performance in organism from emission of radiation at a given wavelength. A transistor based on a single electron move has been constructed. In other words, control over a single electron has been achieved. The studies in this field are so advanced that one can say of a new discipline – nanomedicine. Countries of high scientific creativity (e.g. Japan, USA, Germany, United Kingdom, France) set aside almost 1 billion dollars a year for such studies. * Goetel Walery (1899 – 1972) – Polish geologist, traveller, activist for nature conservation. A significant advance in targeted synthesis of new drugs, molecules with specific atoms, of a given geometry and a system of orbitals has been done. This was achieved by computer simulation, which requires machines of extremely high computational power. Such machines are being predicted by nanotechnology. Recently crystallographic model of abnormal protein from neoplastic cells in chronic myeloid leukemia was obtained with use of computer. As a consequence – for the first time, following many attempts – was matched an active, with possibly most correlated structure, chemical compound (STI-571) that proved to be an effective drug at early stage of the disease (at later stages some patients produce drug-resistant mutations of neoplastic cells). Complex electronic neural networks are another significant achievement of science and technology. They process and even produce new programmes. Numerous converters and integrated circuits connected at random create complex systems displaying surprising properties of “artificial intelligence”. They show ability to learn and self-regulate while existing without a programme and network database. They represent models to simulate and analyze biological systems – from organism to ecosystem and biosphere. An example is cyber-ecosystem Tierry in which computer programmes bearing properties of organism undergo mutations and evolve into a variety of programmes including those using instructions of adjacent ones (“parasites”) or those simplified that replicate by groups with own instructions. It appeared possible to convert the signals from cat visual thalamus cells in the way the image seen by cat (human face) was displayed on the screen, what gives a prospect for producing “replaceable parts” for human brain and even constructing electronic connections to operate a machine with thoughts. Successfully alterations were converted in potential of brain cortex in a paralyzed patient, whose images, move with his hand or leg, into a code understandable for computer to shift a cursor indicating proper letters on the screen. Spacecraft technologies helped to build artificial heart (fuel pumps rule) and devices for fast tests (body temperature for 2 s, blood analysis for 30 s). An advance in renewable (power of wind and water, processed wastes, energy of the Earth interior and oceans, improved use of solar radiation) and even new energy sources arrangement can be expected. Silicon nitride was obtained, which - combined with oxygen or nitrogen - can represent a safe, easy to store and transport source of energy that can easily be used in power stations not producing carbon dioxide but sand as a result of use. Thanks to biotechnology and genetic engineering many new varieties of plants with expected properties and higher crops volume have been obtained. In the European Union they account for 60% of foods (such products should be marked as GMO). Cultivable plants able to assimilate nitrogen from air (about 30 genes) as well as transgenic trees of fast and extensive growth in wood mass are planned to be created. Some races of breeding animals have been saved from extinction. A transformation of malarial anthropophilic anopheles’ strain to zoophilic one safe to humans is underway. A gene coding a toxin active against trypanosoma causing Chagas disease was built-in into the genome of bacteria inhabiting the alimentary tract of hemipteran, which carries these protozoa. Also, genome of gnats was modified to prevent them from transmission of yellow fever to humans. Methods to avoid development of microbe resistance to drugs are planned as well as ways to use bacteriophages against bacteria harmful to humans. Experiments on production of human organs in transgenic animals for xenotransplantation are carried out. Cultures of maternal cells which can transform to some human cells or tissues were obtained. Insulin and a vaccine against virus hepatitis B, both obtained by genetic engineering, are applied in medicine, also in Poland. Successful attempts to “teach“ dendritic cells to recognise neoplastic proteins are reported. Encouraging are prospects of use monoclonal antibodies in medicine. Introduction of appropriate gene into patients suffering from the absence of protein coded by this gene is planned (partial success was achieved in haemophilia). Biotechnology and genetic engineering not always have positive results. Introduction of toxin Bt (Bacillus thuringiensis israelensis) gene into maize for controlling its pests appeared to be fatal for other insects present in the environment. Safety of GMO product has not been proved nor denied. Greenpeace representative (2001) protested against introducing transgenic organisms to the environment since genetic engineering deemed them “pieces containing DNA” and results of such action are irreversible, fixed and bear unknown risk. The lack of harmful evidence does not mean the safety for consumers and environment. More attention is paid to troubles in growing such plants – the necessity to purchase approved seeds every year, intensity of culture resulting sometimes in environment degradation, decrease in biodiversity, pollution of ecosystem with new genes (hybrids of transgenic mustard, oat or maize with related weeds have been detected). An allergic action of new proteins from food should also be borne in mind. The same is true for possibility of transmission of antibiotic resistance genes to bacteria inhabiting the alimentary tract. The Polish law (2001) - more strict than in the European Union - established the obligation of obtaining a permission for any researches conducted in genetically modified structures. There are also objections against creating animal-human chimeras - no matter the purpose, including organs (heart, liver, kidneys) transplantation. In the USA opponents of “anthropoanimals” applied for patent protection of chimeras in order to prevent their creating. Some states (USA) put in force the law forbidding reproductive or therapeutic cloning (obtaining maternal cells from several-day human embryos) whereas in the UK therapeutic cloning is permitted. An infection with prions and viruses as a result of xenotransplantation of transgenic organs in human is emphasized. In Poland one should take into account the necessity of harmonization of the applied and medical ecology law to the law of the European Union. The Universal Declaration on the Human Genome and Human Rights unanimously adopted by the member states of UNESCO (1997) emphasizes the fact that human genome represents the foundation of humankind unity, dignity and diversity. None of genome investigations or their use in contradiction to human dignity can be considered as more important than human rights and fundamental freedoms. The International Bioethics Committee of UNESCO contributes to the promotion of the rules of this declaration and the studies of emerging issues. Summing-up results and opportunities of present-day medical ecology, it is worth bearing in mind not only the fact that every day some dozens of species become extinct irreversibly but also that every 8 seconds a child dies from drinking contaminated water and one out of three suffers from malnutrition. According to the recent estimations our health depends in 5-10% on genetic factors, in 10-20% on medical care, with the rest remaining for the most important: conditions of our biosphere, sociosphere, noosphere, and technosphere. Thus, I am of the opinion that the guideline for medical ecology functions in view of human and his environment should be: “not to damage to not repair”.