Introduction to Environmental Biology (Bio 123) Notes PDF

DOMINICA STATE COLLEGE INTRODUCTION TO ENVIRONMENTAL BIOLOGY (BIO 123) NOTES Week 1 Introduction to Environmental Biology and Sustainability Objectives 1. Define the terms environment, biosphere, ecology, ecosystem, E...

DOMINICA STATE COLLEGE INTRODUCTION TO ENVIRONMENTAL BIOLOGY (BIO 123) NOTES Week 1 Introduction to Environmental Biology and Sustainability Objectives 1. Define the terms environment, biosphere, ecology, ecosystem, Environmental Biology, biome. 2. Identify at least four (4) global environmental challenges. 3. Apply the systems approach to the study of Environmental Biology. 4. Describe the general development and successes of modern environmentalism. 5. Write a summary of Rachel Carson’s Silent Spring. 6. Differentiate between the terms sustainability and sustainable development. 7. Describe the relationship between society, economics and environment in sustainable development Environmental biology: has a wider connotation than ecology and includes human interactions with the environment. Ecology: the study of the interaction of organism with one another and with their physical and chemical environment. Environment: the surrounding of an organism- air, water, terrestrial features. It is made up of biotic and abiotic components. Biosphere: the entire region in which organisms exists – the waters of the earth, the surface of rocks soils and sediments of its crust and the lower regions of the atmosphere. The terrestrial portion of the biosphere is divided into biomes. A biome is a major life zone characterized by the dominant plant life present e.g. temperate grassland, coniferous forests, tropical rainforest, and deciduous woodlands. Ecosystem: a community of organisms interacting with one another and with their physical environment through a flow of energy and a cycling of nutrients e.g. forests, rocky sea shore, pond, lake, tree. Why study environmental biology? Identify some environmental challenges which are global in nature. 1. Uncontrolled human population growth which will put a severe strain on ecosystem goods and services 2. Global climate change and atmospheric changes 3. Loss of biodiversity 4. Loss of unique ecosystems which provide us with good and services Of course there are other localized challenges such as, but not limited to those below: a. Desertification b. Pollution c. Deforestation System approach to the study of Environmental Biology The Environment as a System Systems in nature – ecosystems where air, water, soil and living organisms work together. It is a whole, made up of components which are inter-related Systems are dynamic and complex whole, interacting as a structured unit where energy, matter and information flow among the different elements that make up the system. The entire planet/biosphere functions as a system and when we study the environment we must see it as a whole with all parts being connected. General Development of Modern Environmentalism This critical movement began in earnest in 1962. 1962 – Rachel Carson, a Marine Biologist, published Silent Spring calling attention to the threat of toxic chemicals to people and the environment. 1967 – the Torrey Canyon oil tanker ran aground and spills 117,000 tons of oil into the mouth of the North Sea in the UK. This prompted legal changes which made ship owners liable for all spills. 1968 – Paul Ehrlich published The Population Bomb describing the threats of a rapidly growing human population. The first UN Biosphere Conference in Paris to discuss global environemental problems – pollution, resource loss and wetland destruction 1970 - First Earth Day was observed in the USA to protest environmental abuses 1992 – United Nations Conference on Environment and Development in Rio de Janiero to develop a document called Agenda 21 to guide development in sustainable directions into and through the 21st century. It addressed issues such as climate change, biodiversity loss, principles for sustainable forestry management and increased funding for developed countries. Five years later there was more failure than progress in these areas. 2001 – World Summit on Sustainable Development (WSSD) was held in Johannesburg to address the fact that most of the previous agreements were not implemented 2015 - COP 21 was held in Paris to address the issue of climate change and global warming. SUMMARY OF THE IMPORTANT ASPECTS OF RACHEL CARSON’S NOVEL "Things Go Out of Kilter" Carson was happiest writing about the strength and resilience of natural systems. Her booksUnder the Sea Wind, The Sea Around Us (which stayed on the New York Times bestseller list for 86 weeks), and The Edge of The Sea were hymns to the inter-connectedness of nature and all living things. Although she rarely used the term, Carson held an ecological view of nature, describing in precise yet poetic language the complex web of life that linked mollusks to sea-birds to the fish swimming in the ocean's deepest and most inaccessible reaches. DDT, the most powerful pesticide the world had ever known, exposed nature's vulnerability. Unlike most pesticides, whose effectiveness is limited to destroying one or two types of insects, DDT was capable of killing hundreds of different kinds at once. Developed in 1939, it first distinguished itself during World War II, clearing South Pacific islands of malaria-causing insects for U.S. troops, while in Europe being used as an effective de-lousing powder. Its inventor was awarded the Nobel Prize. When DDT became available for civilian use in 1945, there were only a few people who expressed second thoughts about this new miracle compound. One was nature writer Edwin Way Teale, who warned, "A spray as indiscriminate as DDT can upset the economy of nature as much as a revolution upsets social economy. Ninety percent of all insects are good, and if they are killed, things go out of kilter right away." Another was Rachel Carson, who wrote to the Reader's Digest to propose an article about a series of tests on DDT being conducted not far from where she lived in Maryland. The magazine rejected the idea. Silent Spring Thirteen years later, in 1958, Carson's interest in writing about the dangers of DDT was rekindled when she received a letter from a friend in Massachusetts bemoaning the large bird kills which had occured on Cape Cod as the result of DDT sprayings. The use of DDT had proliferated greatly since 1945 and Carson again tried, unsuccessfully, to interest a magazine in assigning her the story of its less desirable effects. By 1958 Carson was a best-selling author, and the fact that she could not obtain a magazine assignment to write about DDT is indicative of how heretical and controversial her views on the subject must have seemed. Having already amassed a large quantity of research on the subject, however, Carson decided to go ahead and tackle the DDT issue in a book. Silent Spring took Carson four years to complete. It meticulously described how DDT entered the food chain and accumulated in the fatty tissues of animals, including human beings, and caused cancer and genetic damage. A single application on a crop, she wrote, killed insects for weeks and months, and not only the targeted insects but countless more, and remained toxic in the environment even after it was diluted by rainwater. Carson concluded that DDT and other pesticides had irrevocably harmed birds and animals and had contaminated the entire world food supply. The book's most haunting and famous chapter, "A Fable for Tomorrow," depicted a nameless American town where all life -- from fish to birds to apple blossoms to human children -- had been "silenced" by the insidious effects of DDT. First serialized in The New Yorker in June 1962, the book alarmed readers across America and, not surprisingly, brought a howl of indignation from the chemical industry. "If man were to faithfully follow the teachings of Miss Carson," complained an executive of the American Cyanamid Company, "we would return to the Dark Ages, and the insects and diseases and vermin would once again inherit the earth." Monsanto published and distributed 5,000 copies of a brochure parodying Silent Spring entitled "The Desolate Year," relating the devastation and inconvenience of a world where famine, disease, and insects ran amuck because chemical pesticides had been banned. Some of the attacks were more personal, questioning Carson's integrity and even her sanity. Vindication Her careful preparation, however, had paid off. Anticipating the reaction of the chemical industry, she had compiled Silent Spring as one would a lawyer's brief, with no fewer than 55 pages of notes and a list of experts who had read and approved the manuscript. Many eminent scientists rose to her defense, and when President John F. Kennedy ordered the President's Science Advisory Committee to examine the issues the book raised, its report thoroughly vindicated both Silent Spring and its author. As a result, DDT came under much closer government supervision and was eventually banned. The public debate moved quickly from whether pesticides were dangerous to which pesticides were dangerous, and the burden of proof shifted from the opponents of unrestrained pesticide use to the chemicals' manufacturers. The most important legacy of Silent Spring, though, was a new public awareness that nature was vulnerable to human intervention. Rachel Carson had made a radical proposal: that, at times, technological progress is so fundamentally at odds with natural processes that it must be curtailed. Conservation had never raised much broad public interest, for few people really worried about the disappearance of wilderness. But the threats Carson had outlined -- the contamination of the food chain, cancer, genetic damage, the deaths of entire species -- were too frightening to ignore. For the first time, the need to regulate industry in order to protect the environment became widely accepted, and environmentalism was born. Carson was well aware of the larger implications of her work. Appearing on a CBS documentary about Silent Spring shortly before her death from breast cancer in 1964, she remarked, "Man's attitude toward nature is today critically important simply because we have now acquired a fateful power to alter and destroy nature. But man is a part of nature, and his war against nature is inevitably a war against himself?[We are] challenged as mankind has never been challenged before to prove our maturity and our mastery, not of nature, but of ourselves." One of the landmark books of the 20th century, Silent Spring's message resonates loudly today, even several decades after its publication. And equally inspiring is the example of Rachel Carson herself. Against overwhelming difficulties and adversity, but motivated by her unabashed love of nature, she rose like a gladiator in its defense. (END OF SUMMARY) SOURCE: HTTP://WWW.NRDC.ORG/HEALTH/PESTICIDES/HCARSON.ASP SUSTAINABILITY This is a central theme in environmental science. Defined by the Brundtland Commission 1984 Sustainable development is development which meets the needs of a current generation without compromising future generation’s ability to achieve theirs.. This raises conflict of inter (between generations) and intra (within) generational equity and is a multi- dimensional interaction which focuses on three pillars: A. Society – (is it socially acceptable) The Social Equality pillar of sustainable development focuses on the social well-being of people. The growing gap between incomes of rich and poor is evident throughout the world with the incomes of richer households increasing relative to the incomes of middle- or lower- class households. B. Economics – (is it economically feasible) Economic Growth is the pillar that most groups focus on when attempting to attain more sustainable efforts and development. In trying to build their economies, many countries focus their efforts on resource extraction, which leads to unsustainable efforts for environmental protection as well as economic growth sustainability. C. Environment –( is it economically viable) Environmental Protection has become more important to government and businesses over the last 20 years, leading to great improvements in the number of people willing to invest in green technologies. The concerns of sociologists, economists and ecologists must intersect in order to achieve sustainable solutions in a society. DISCUSS (1) Can sustainability be achieved? (2) It is clear that poverty is inextricably linked to environmental degradation. How can we continue improvements in human welfare within the limits of the world’s resources? Sustainability and sustainable development - What is sustainability and what is sustainable development? Defined by the Brundtland Commission in 1987, who documented the sustainable development definition as: "Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs." This implies that we need to look after our planet, our resources and our people to ensure that we can live in a sustainable manner and that we can hand down our planet to our children and our grandchildren to live in true sustainability. What is sustainability? The three pillars of sustainability But what is sustainability? The definition of sustainability may be taken further and it is widely accepted that to achieve sustainability we must balance economic, environmental and social factors in equal harmony. This may be illustrated with a sustainability Venn diagram, as shown below: Sustainability Venn Diagram So to achieve true sustainability we need to balance economic, social and environmental sustainability factors in equal harmony. These may be defined as:  Environmental Sustainability: Environmental sustainability means that we are living within the means of our natural resources. To live in true environmental sustainability we need to ensure that we are consuming our natural resources, such as materials, energy fuels, land, water...etc, at a sustainable rate. Some resources are more abundant than others and therefore we need to consider material scarcity, the damage to environment from extraction of these materials and if the resource can be kept within Circular Economy principles. Environmental sustainability should not be confused with full sustainability, which also need to balance economic and social factors.  Economic Sustainability: Economic sustainability requires that a business or country uses its resources efficiently and responsibly so that it can operate in a sustainable manner to consistently produce an operational profit. Without an operational profit a business cannot sustain it's activities. Without acting responsibly and using its resources efficiently a company will not be able to sustain it's activities in the long term.  Social Sustainability: Social sustainability is the ability of society, or any social system, to persistently achieve a good social well being. Achieving social sustainability ensures that the social well being of a country, an organisation, or a community can be maintained in the long term. Taking these three pillars of sustainability further if we only achieve two out of three pillars then we end up with:  Social + Economic Sustainability = Equitable  Social + Environmental Sustainability = Bearable  Economic + Environmental Sustainability = Viable Only through balancing economic + social + environmental can we achieve true sustainability. So what is the difference between sustainability and sustainable development? On the surface there is little difference but a good way of distinguishing between the two is with the quote below: "Sustainable development is the pathway to sustainability" Source: http://www.circularecology.com/sustainability-and- sustainable-development.html#.VATVffldXsU Week 2 Sustainability Objectives 1. Discuss how the unifying themes contribute to sustainability 2. Identify examples of the four groups of ecosystem goods and services provided to us by the natural world 3. Discuss the effect of humans on the natural world 4. Outline the transitions necessary for humans to move to a sustainable future 5. Distinguish between the terms biotic and abiotic, habitat and niche, organic and inorganic, autotrophs and heterotrophs, 6. Differentiate amongst predators, parasites and pathogens, trophic levels, food chains and food web 7. Define the terms species, population, community and ecosystem 8. Differentiate between conditions and resources 9. Discuss the role of climate, micro-climate and other abiotic factors in influencing the distribution of organisms. Three Unifying Themes 1. Sustainability – the practical goal toward which our interactions with the natural world should be working.  A system or process is sustainable if it can be continued indefinitely, without depleting the energy or materials required to keep it running. The term was first applied to the idea of sustainable yields in human endeavours/activities such as forestry and fishery. Trees, fish and other biological species normally grow and reproduce at rates faster than those required just to keep their populations stable. This built in capacity allows every species to increase or replace a population following some natural disaster. It is possible then to harvest a certain percentage of trees or fish every year without depleting the forest or fish population below a certain base number. As long as the number harvested stays within the capacity of the population to grow and replace itself, the practice can be continued indefinitely. The harvest then represents a sustainable yield. It becomes unsustainable only when trees are cut or fish are caught at a rate that exceeds the capacity of their present population to grow and reproduce. The notion of sustainability can be extended to include ecosystems. Sustainable ecosystems are entire natural systems that persist and thrive over time by recycling nutrients, maintaining a diversity of species, and using the sun as a source of sustainable energy. All ecosystems are enormously successful at being sustainable. Apply the concept of sustainability to human systems, we say that a sustainable society is a society in balance with the natural world, continuing generation after generation, neither depleting its resource base by exceeding sustainable yields nor producing pollutants in excess of nature’s capacity to absorb them. Many primitive societies were sustainable in this sense for thousands of years. In modern times, many of our interactions with the environment are not sustainable – We see global trends such as:  Decline of biodiversity and essential ecosystems  Increased emission of greenhouse gases  Excessive use of resources and over consumption  Increased pollution  Heavy exploitation of natural resources to meet needs in developing countries We must practice sustainable development: this means different things to different people. Economists are mainly concerned with growth, efficiency, and the optimum use of resources. Sociologists mainly focus on human needs and on concepts like equity, empowerment, social cohesion and cultural identity. Ecologists show their greatest concern for preserving the integrity of natural systems, for living within the carrying capacity of the environment and for dealing effectively with pollution. It can be argued that sustainable solutions can be found mainly where the concerns of these three groups intersect.  2. Sound Science Science forms the foundation of understanding controversial issues. In essence, science is simply a way of gaining knowledge and that way is called the scientific method. The term science further refers to all the knowledge gained through that method. We employ the term sound science to distinguish legitimate science from what can be called junk science – information that is presented as valid science but does not conform to the rigors and methods and practice of legitimate science. Sound science involves a disciplined approach to understanding how the natural world works, an approach that has become known as the scientific method. Junk science traditionally refers to information that is presented as scientifically valid but that does not conform to the rigors imposed by the scientific community. It involves a. the presentation of selective results, b. politically motivated distortations of scientifically sound information, c. the publication of poor work in quasi-scientific (unreviewed) journals and books 3. Stewardship - The actions and programs that manage natural resources for the common good. Stewards are those who care for something that they do not own and that they will pass to the next generation. Modern day stewardship, therefore, incorporates an ethic that guides actions taken to benefit the natural world and other people. It recognises even our ownership of land is temporary, the land will be there after we die, and others will own it, in turn. Stewardship is compatible with the goal of sustainability but it is different in that stewardship deals more directly with how sustainability is achieved – what actions are taken and what values and ethical considerations are behind those actions. Sometimes stewardship leads people to try to stop the pollution that is degrading human neighbourhoods and health eg Rachel Carson and Silent Spring. Stewardship is a matter of everyday people caring enough for each other and for the natural world that they do things that are compatible with that care. This includes actions such as: 1. Recycling 2. Pollute less and use less energy 3. Turn off lights when not in use 4. Voting for green candidates 5. Staying informed on environmental issues 6. Avoid excessive consumption Ecosystem capital The good and services provided by the natural and managed ecosystems. They fall under four categories: Provisioning, Regulating, Supporting, Cultural. 1. Provisioning: food, fresh water, fuel wood, fiber, biochemicals, genetic resources 2. Regulating : climate regulation, disease control, flood control, detoxification 3. Supporting: soil formation, nutrient recycling, pollination, primary production, oxygen production. 4. Cultural: spiritual, recreational, aesthetic, inspirational, educational, communal Ecological footprint – the concept of measuring the demand placed on Earth’s resources by individuals from different parts of the world, involving calculation of the natural area required to satisfy human needs in housing, food, transportation, consumer goods and various services such as absorbing wastes. The ecological footprint of an American is 12.6 acres/person and that of a typical Indian national is 1 acre/person. The 2.5 billion persons added to the population by 2050 will have to be fed clothed and housed. The increase will be in developing countries. It is in these same countries where 1.2 billion experience severe poverty, lack sufficient income to meet the basic needs of food, shelter and clothing. As poorer countries seek to improve their status and undergo economic development their ecological footprint will grow and the net impact of those added to the population in the next half century is almost unimaginable. Stabilising growth in the developing countries is vitally important for the natural world. The effect of humans on the natural world They have replaced natural systems with agriculture and urban and suburban developments. Made heavy use of the remaining ‘natural systems’ for wood, food and other commercial products By-products of our economic activities have polluted and degraded ecosystems everywhere What is now needed is an Environmental Revolution which are the transitions necessary to move human systems from its present state to one which is more sustainable. The transitions which humans need to make towards a more sustainable future are: 1. A demographic transition – from a continually increasing human population to one which is more stable. 2. A 3. resource transition – to an economy that relies on natures income and protect ecosystem capital from depletion. 4. A technological transition – from pollution intensive economic production to more environmentally friendly processes. 5. A political/sociological transition – to societies that embrace a stewardly and just approach to people’s needs and in which large scale poverty is eradicated. 6. A community transition – from the present car-dominated urban sprawl of developed countries to the ‘smart growth’ concepts of smaller functional settlements and more liveable cities Ecology Define the terms: a. Biotic b. Abiotic c. Habitat d. Niche e. Organic f. Inorganic g. Predator h. Parasite i. Pathogens j. Trophic level k. Food chain and food web l. Species m. Population n. Community o. Ecosystem Conditions and resources The abiotic environmental factors (chemical and physical) are divided into conditions and resources. Conditions –abiotic factors that vary in space and time but are not used up or made unavailable to other species eg temperature, wind, pH, salinity, fire, depth and turbidity of water, currents. Resources may be biotic or abiotic factor. Some examples are water, chemical, nutrients, light, oxygen, spatial needs. Resources, unlike conditions, can be objects of competition between individuals or species. Optimum, zones of stress, limits of tolerance Different species thrive under different environmental conditions; Some very wet – ferns and mosses Some very dry – cacti Some freezing – arctic moss, caribou moss Some shade – anthuriums Optimum – a certain level at which organisms do best. At lower or higher levels organisms do less well. Optimum maybe a range of several degrees (units) , so it is common to speak of an optimal range. The entire span that allows any growth at all is called the RANGE OF TOLERANCE. The points at the high and low end of the range of tolerance are called the limits of tolerance. Zones of stress Regions where species find conditions tolerable but suboptimal. The species survive, but under stress. Law of limiting factors Any factor that limits growth is called – limiting factor. The limiting factor may be a problem of too much or too little eg over watering and under watering plants. ROLE OF CLIMATE IN THE DISTRIBUTION OF ORGANISMS CLIMATE a description of the average temperature and precipitation that may be expected on each day throughout the entire year. A given climate will only support those species that find the temperature and precipitation levels are optimal and at least within the range of tolerance. A species will be excluded from a region where any condition is beyond its range of tolerance. 1. Micro climate and other abiotic factors which affect the distribution of organisms  The conditions found in a specific localised area is referred to as microclimate. Other abiotic factors include a. Soil type b. Topography c. Salinity d. pH 2. Biotic factors a. Herbivory b. Competition c. Predation 3. Physical barriers – oceans, desert and mountain ranges that species are unable to cross. Humans also erect dams, road ways, above ground pipelines,cities and farms, that may block the movement of populations and may cause their demise. Week 3 Ecology Objectives 1. State the role of producers, consumers and decomposers in an ecosystem 2. Construct food webs for various ecosystems using information provided 3. Participate effectively in a group setting 4. Describe the various types of symbiotic relationships found in ecosystems 5. Explain they types of competition among organisms 6. Define the terms competitive exclusion and resource partitioning Food chains Show a flow of energy in an ecosystem, shows who eats whom. All energy comes from the sun and enter the ecosystem through photosynthesis. Producers harness the sun’s energy and this is passed up the chain. Only 10 percent of food from one level gets to the other level, and 90 percent is lost. Please note well. Food chains do not generally exist in nature because very few organisms eat only one type of food source, so food webs are very common instead. In a food chain an animal occupies only one trophic level while in a food web an organism can occupy more than on trophic level as you will see when you complete the practice worksheet. The energy loss is explained below under the section “Fate of Food”. Food Web: See the resource package for practice on Food Webs and Interspecific Interactions https://www.youtube.com/watch?v=iYKfkD481cI Week 4 Ecology Objectives 1. Identify the key elements which make up living organisms and the compounds in which they are found 2. Describe the role of producers and consumers in ecosystems 3. Explain the fate of food in living animals 4. Describe the carbon, nitrogen and phosphorus cycles 5. Discuss the human impacts on the cycles stated above 6. Define the terms biotic potential, environmental resistance and give factors of each and their role in controlling growth of populations in the wild 7. Define the term carrying capacity and explain its role in population dynamics ECOSYSTEMS HOW THEY WORK Matter – anything that has mass and occupies space Atoms - the building blocks of matter. Molecule – two or more atoms bonded together in a specific way Compound – two or more different kinds of atoms bonded together. Three spheres – atmosphere, lithosphere, hydrosphere make up the biosphere. During growth and decay atoms move from the environment into living things and then return to the environment. The environment consists of lithosphere, atmosphere, and hydrosphere. They key elements in living things are characterised by six key elements carbon (C), hydrogen (H), oxygen (O), nitrogen (N), phosphorus (P) and sulphur (S). Organic compounds – the chemicals which make up the bodies of living organisms. Producers and Photosynthesis 6CO2 + 6H2O C6H12O6 + 6O2 Chlorophyll in the cells of the plant absorbs the kinetic energy of light and uses it to remove the hydrogen atoms from water. These hydrogen atoms combine with carbon dioxide to form glucose. After the hydrogen atoms are removed the oxygen atoms combine with each other to form oxygen gas which is released into the atmosphere. The glucose produced by photosynthesis serves three purposes; 1. It combines with nitrogen, phosphorus, sulphur and other minerals to form all the organic molecules needed by the plant. 2. The plant uses some glucose and other materials for its own use 3. Some material is stored for future use e.g. starch in potatoes and oils in seeds. As plants in an ecosystem convert sunlight into new organic matter they are ‘setting the table” for the rest of the ecosystem. Consumers Consumers get energy from the food they eat. This food is first digested and the molecules absorbed through the blood stream and transported to the individual cells. Inside each cell glucose is broken down by respiration, the reverse of photosynthesis: 6O2 + C6H12O6 6CO2 + 6 H2O THE FATE OF FOOD. 1. 60 -90% is oxidised for energy 2. 10 – 40 % is converted to body tissue 3. Cellulose passes out undigested. In an ecosystem therefore, only the portion of the food which becomes the body tissue of the consumer can become food for the next organism in the food chain. Detritus feeders and decomposers Detritus is largely cellulose. Termites have decomposition microbes in their gut which help to digest cellulose. They maintain a mutualisitic relationship. Most decomposers use oxygen for respiration which breaks water down into carbon dioxide, water, minerals and nutrients and release heat in the process. Summary As primary producers are consumed by herbivores, energy is transferred from producer to consumer, thus energy flow in an ecosystem is characterised by how the energy moves from one trophic level to another. As this occurs only a small fraction is actually passed on, this is due to three things: 1. Much of the preceding level is standing biomass and is not consumed. 2. Much of what is consumed is used for energy 3. Some of what is consumed is undigested and passes through the organism. As energy flows through ecosystems, we must understand that energy flows one way through ecosystems and is one of the fundamental processes that make ecosystems work. The other process is the cycling of nutrients and other elements. Cycles: See work package for diagram of the cycles Biotic Potential v/s Environmental Resistance Biotic potential - The ability of populations to increase. The following factors affect biotic potential a. Reproductive rate b. Ability to migrate or disperse seeds c. Ability to invade new habitats d. Defense mechanisms e. Ability to cope with adverse conditions To increase the population however, the young must survive and produce in turn. Survival through the early growth stages to become part of the breeding population is called recruitment. Reproductive Strategies There are two common reproductive strategies in the natural world 1. Produce massive numbers of offspring but then leave them to survive at the whims of nature. Organisms in this strategy are usually small with rapid reproduction rates and short life spans eg rats and roaches. 2. The second strategy is to have a much lower reproductive rate but then care for and protect the young until they can compete for resources with the adult members of the population. Organisms adapted to such strategy are larger, longer lived and well adapted to normal environmental fluctuations eg elephants. Environmental Resistance The combination of all biotic and abiotic factors that may limit a populations increase. Population explosions are seldom seen in natural ecosystems because biotic and abiotic factors tend to cause mortality in populations. Abiotic factors include Unusual temperatures Moisture Light Salinity pH Biotic Factors include Predators Disease Parasite Competitors Carrying Capacity The carrying capacity is the maximum population that a given habitat can support without being degraded over the long term – a sustainable system. If a population exceeds the habitats carrying capacity, it will undergo a J curve crash Density dependence The size of a population generally remains within a certain range when environmental resistance factors are density dependent. This is, as a population density (number of individuals /unit area) increases, environmental resistance becomes more intense and causes an increase in mortality such that population growth ceases or declines. Consequently, as the population density increases, environmental resistance lessens and allows the population to recover. This balancing act is clear in the wolf moose scenario. Factors in the environment that can cause mortality can also be density independent ie. Their effects is independent of the density (numbers) in the population. This if frequently true of abiotic factors such as freezing and fire. Although density independent factors can be important sources of mortality, they are not involved in maintaining population equilibrium. Week 5 Ecology/ Human Population Growth Objectives 1. Describe the two basic population growth curves and state where they may be found in nature (Wolf moose case study) 2. Discuss the role of a keystone species in an ecosystem (HW… see below) 3. Evaluate the impacts invasive species on ecosystems (HW) 4. Define the terms ecological succession, pioneer species, facilitation, climax ecosystem 5. Differentiate between primary and secondary succession 6. Explain the process of primary succession on land 7. State the factors which caused the human population to remain constant for many centuries 8. State the factors which caused the human population to grow rapidly 9. Explain the economic disparity between rich and poor nations and the difference in population growth 10. State four factors which contribute to the desire for large families Ecosystems: How they change Dynamics of Natural Populations Studies of populations in ecosystems show that they remain constant ie birth = deaths and this is called population equilibrium. However, populations are capable of growth under certain conditions. Population Growth Curves of Organisms Exponential Increase- every species has the capacity to increase its population when conditions are favourable. Under ideal conditions, growth will be exponential ie growth by a factor of 10 (10. 100, 1000, 100000). This is called an exponential increase and results in a population explosion. If we plot the numbers, the pattern produced is called a J curve. If a population is reduced to a low level and conditions return to normal the population may increase exponentially for a while but one of two things may occur. a. Natural mechanisms may cause the population to level off and continue in dynamic equilibrium (known as the S curve) b. In the absence of natural enemies, the population keeps growing until it exhausts all of its natural resources, usually food and dies off precipitously due to starvation an disease and produces a reverse of the J curve J curves come about when there are unusual disturbances such as 1. Introduction of foreign species 2. Elimination of a predator 3. Sudden alteration of habitats Equilibrium populations The outstanding feature of natural ecosystems are that they are made up of populations that are in dynamic equilibrium represented by S curves. In conclusion, whether a population grows, remains stable or decreases is a result of an interplay between its biotic potential and environmental resistance. In general, a population biotic potential remains constant so, its changes in the environmental resistance that allows populations to increase or cause them to decrease. Population balance is a dynamic balance ie births and deaths are occurring continuously and the population may fluctuate around a median. This dynamic balance is evident in the study of wolf and moose on Isle Royale. https://en.wikipedia.org/wiki/Wolves_and_moose_on_Isle_Royale#:~:text=The%20single%20predator%2Dsingle%20pre y,study%20for%20over%2050%20years.&text=The%20relationship%20between%20wolves%20and,research%20study% 2C%20begun%20in%201958. http://www.mhhe.com/Enviro-Sci/CaseStudyLibrary/Regional/Midwest/CaseStudy_WolvesandMooseonIsleRoyale.pdf Further Reading: 1. Define the term keystone species and give an example of one such species and its role in the eocosystem. 2. Please watch all of the youtube videos on “Crash Course Ecology” Ecological Succession Please see Classe 365 for the handout. HUMAN POPULATION DYNAMICS OF HUMAN POPULATION GROWTH ORGANISMS live as members of populations (individuals of the same spp that live together in a particular area). They potentially interbreed with one another, share the same habitat and the same pool or resources that the habitat provides. HUMAN POPULATION EXPANSION AND ITS CAUSE Considering all the thousands of years of human history, the recent rapid expansion of the global human population is a unique event – a phenomenon of the past 100 years. The UN Population Division projects that the world population will pass the 7 billion mark by 2013 and the 8 billion mark by 2028 and the 9 billion mark by 2052, before the population finally levels off at around 10 billion by the end of the 22nd century. The main reason for the slow growth of populations prior to the early 1800’s was the presence of fatal diseases, epidemics and famines. This kept the human population in balance with natural enemies, mainly diseases- and other aspects of environmental resistance. High reproductive rates were largely balanced by high mortality, especially among infants and children. In the late 1800’s there were significant improvements in medicine, sanitation and nutrition which brought about spectacular reductions in mortality especially among infants and children while the birth rates remained high. From a biological point of view, the human population began growing almost exponentially, as does any population once it is freed from natural enemies and other environmental restraints. The projected leveling off at around 10 billion raises the question as to whether Earth can sustain such large numbers - Where are the additional billions of people going to live and how are they going to be fed, clothed, housed and educated and otherwise cared for? Will enough energy and material resources be available for them to enjoy a satisfying life? What will the natural environment look like by then? FACTORS CONTRIBUTING TO POPULATION GROWTH In the last century the global human population has undergone an unprecedented expansion, more than tripling in numbers. Remarkable changes in technology and substantial improvements in human well-being have accompanied this growth  Greater access to health care   Low infant mortality  Longer life span  Better ways of producing and storing food  Better housing  More control over their food supply Feel free to add more answers based on class discussion. The World Bank divides the nations of the worlds into three main economic categories according to average per capita gross national income. a. High income, highly developed industrialized countries – USA, Japan, Canada, Australia (Please find the others) B. Middle income, moderately developed countries – countries of Latin America and South America, northern and southern Africa (Find others please) c. Low income developing countries – eastern western and central Africa and India (Find others) The high income countries are referred to as developed while the others are called developing countries. The distribution of wealth among the world is unbelievable. The highly developed countries make up 16% of the world’s population yet the control 81% of the world income while the low income developing countries with 41% of the world’s population, control only 3.4% of the worlds gross national income. As poverty is one of the major drivers of environmental degradation, there is work to do in all countries to address the general problem of poverty. Reasons for large families in developing countries 1. Old age security – they feel that they will get a better chance of being cared for by their children 2. Infant mortality and childhood mortality – due to high death rate in some countries, women make extra children to ‘compensate’ 3. Helping hands – this is especially true for societies which practice agriculture 4. The status of women increases and barrenness is seen as being a curse. Women especially desire to bear sons 5. Lack of accessibility to contraceptives Week 6 Human Population Growth Objectives 1. Assess the impact on the environment of the different problems caused by different populations (rich and poor) 2. Interpret and analyse population pyramids 3. Propose solutions to curb population growth poor countries Different Populations, Different Problems Ecologists Paul Ehrlich and John Holdren proposed a formula to account for the human factors that contribute to environmental pollution and depletion of resources. They reasoned that human pressure on the environment was the outcome of three factors: Population, affluence and technology. They offered the following formula: I = P x A x T According to this equation called the IPAT formula the environmental impact ( I) is proportional to population (P), multiplied by the affluence of the average lifestyle (A) and multiplied by the level of technology of the society (T). Although the equation is a simplification, there is broad agreement that these factors play the major role in putting pressure on the environment. In order to reach sustainability, however, all three must be addressed. That is – the population must stabililse, consumption must decrease and stewardly action must increase. READ UP ON ‘ECOLOGICAL FOOTPRINT’. Consequences of Population Growth and Affluence. Prior to the Industrial Revolution populations survived through subsistence agriculture. Natural forests provided firewood, structural materials for housing and wild game for meat. With a small stable population, this system was basically sustainable. Population growth in rich and poor nations As with the disparity of wealth there is a discrepancy in population growth between developed and developing nations. The developed world, with a population of 965 million in mid 2003 is growing at a rate of 0.1% per year and will add less that 1million to the world’s population. The remaining countries whose population was 5.35 billion are increasing at a rate of almost 1.6% per year, adding over 76 million per year – 98 % of population growth is occurring in developing countries. Impact on the environment caused by different populations Environment pressures are not only caused by rapid population growth in developing countries but also the populations in wealthy population stable countries. The people living in these countries have larger ecological footprints. Major world pollution problems including the depletion of the ozone layer, impacts of global climate change, the accumulation of toxic wastes in the environment are largely a consequence of high consumption associated with affluent lifestyles. The developing countries do have a population problem and it is making their progress towards sustainable development that much more difficult. Their people are plagued by poverty, often hungry, poorly educated, out of work, sickened by common diseases and vulnerable to natural hazards such as droughts and floods. They may look with hope to the future but that hope is often crushed by grinding poverty and their needs are great: economic growth, more employment, wise leaders, effective public policies, fair treatment by other nations and especially, technological and financial help from the wealthy nations. In order to negate the effects on the environment the citizens of the developed countries must practice environmental stewardship – wildlife conservation, pollution control, energy conservation and efficiency and recycling may offset, to some extent the negative impact of the consumer lifestyle. In order to reach sustainability we must address the impact on the environment (I = PAT) ie population must stabilise, consumption must decrease and stewardly action must increase. CONSEQUENCES OF POPULATION GROWTH IN DEVELOPING NATIONS Prior to the industrial revolution most of the human population survived through subsistence agriculture but with the rapid population growth, this cannot adequately provide for the needs of the people. What are the impacts of rapid population growth on a population that is largely engaged in subsistence agriculture? As a result, we see six options emerging; 1. Reform the system of land ownership 2. Intensify cultivation of existing land to increase production per unit area 3. Open up new lands for agriculture 4. Migration to cities 5. Engage in illicit activities for income 6. Emigration and immigration IMPOVERISHED WOMEN AND CHILDREN The hardships and deprivation of poverty affect mostly women and children. Men are free to roam and pick up whatever work is available and they keep their wages for themselves. Some men take no responsibility for the children they sire and under the stress of poverty abandon the women and children. Few developing countries have a welfare system to cater to these needs. STREET CHILDREN Women of impoverished children usually end up on the street begging, scrounging through garbage, stealing and sleeping on the street. What adults will they become if they survive? Population growth, poverty and environmental degradation are not separate issues but are very inter- related. AFFLUENCE The USA consumes the largest share of 11 of 20 major commodities, lead per capita consumption of meat (3xmore than average) , lead the world in paper consumption and contribute to the enormous ecological footprint. However, there are amenities such as safe drinking water, sanitary sewage system and sewage treatment and collection and disposal of refuse. Thus many forms of pollution are held in check and we can afford gas and electricity, not destroying the woodlands for fuel wood. In short, the USA can afford conservation and management, better agricultural practices and pollution control, thereby improving our environment. On the dark side,  US leads the world in production of pollutants (use large quantities of fossil fuels), carbon dioxide emissions.  CFCs, chemicals which cause acid rain, emissions of other hazardous chemicals, and nuclear wastes are all the by-products of affluent societies.  11 of the 15 major world fisheries are either fully exploited or over exploited  Oil spills are a by-product of our appetite for energy  Tropical forests are harvested for exotic wood furnishings  Metals, timber, and oil are taken from developing countries to satisfy our need. As more people strive for and achieve greater affluence, such pressures and others like it will mount. So, it is not only the poor, with their large populations which are placing a strain on the environment but also the developed countries with their greater affluence. You will now discuss some of the problems which can arise due to a. Population growth (social, economical and environmental – please be specific don’t just say poverty!) b. Affluence in developed countries POPULATION PYRAMIDS Humans live in groups called populations and the human population has exploded since the 1700’s. Demography is the statistical study of populations. Demography is the science that predicts how population sizes will change in the future. Populations grow if births outnumber deaths and shrink if deaths outnumber births. The future size of a population depends on its present age structure and sex ratio. Age structure- The age structure of a population is the distribution of people among various ages. Populations with large proportion of young individuals tend to grow rapidly because an increasing proportion of their individual are reproductive. Sex ratio – the proportion of males to females in the population is its sex ratio. The number of births is usually directly related to the number of females (Birds – monogamous) A population whose size remains fairly constant through time- stable population. When a population lives in a constant environment for a few generations its age distribution i.e. the number of individuals in different age categories, tend to stabilize. The rate at which a population is expected to grow in the future can be assessed graphically by means of a population pyramid. This is a bar graph displaying the numbers of people in each age category. Males are conventionally shown to the left of the vertical age axis, females to the right. In most human population pyramids the number of older females is disproportionately large compared to the number of older males because females in most regions have a longer life expectancy than males. In general, rectangular pyramids are characteristic of countries whose populations are stable – numbers not growing or shrinking A triangular pyramid is characteristic of a country that will exhibit rapid future growth as most of its population has not entered child bearing years Inverted triangles are characteristic of populations that are shrinking. FIND COUNTRIES WITH EACH OF THE FOLLOWING TYPES OF POPULATION GROWTH PYRAMID OUTLINED ABOVE. For 16 centuries the human population was characterized by slow. This has since changed; the earth’s rapidly growing human population constitutes perhaps the greatest challenge to the future of the biosphere. This population growth places stress on worlds ecosystems and we cannot reasonably expect the biosphere to continue to expand its carrying capacity indefinitely. Please watch the following videos https://www.youtube.com/watch?v=x8yq7DcrTFg https://www.youtube.com/watch?v=fg4lEkmsqbE https://www.youtube.com/watch?v=sSoSYm4AOls How to control population growth in poor countries? A new social direction to curb population growth places emphasis on education. We can curb population growth by 1. Education – increasing the literacy of girls and women can slow population growth as the educated females can pass on knowledge to the family and women who are employed tend to make less children. 2. Lowering infant mortality and improving life expectancy so that the women are assured that the small number children they make will survive to adulthood 3. Making family planning affordable and available so that all can have access. 4. Enhance employment activities for all sectors of the population, especially women and girls. Development is targeted at alleviating the problems of the poorest people. A great deal of focus is on women because not only do they bear children but they are also the primary providers of nutrition, child care, hygiene and early education. When women have more education and some income of their own, they are more likely to spend more money on education and health care for children and less likely to have large numbers of children. https://www.youtube.com/watch?v=wIzPHXY_SAw Week 7 Objectives Water Cycle 1. State the percentage of water available for human use and the source from which it is drawn 2. Describe the water cycle 3. Explain the human impacts on the water cycle 4. Differentiate between between point source and non point source of water pollution 5. State examples of water pollutants 6. Differentiate between bioaccumulation and biomagnification in water bodies and their implication for organisms 7. Describe the sequential process of cultural eutrophication 8. Outline measures to deal with eutrophication Water Cycle B Review A D C E F H G PROCESSES IN THE WATER CYCLE Evaporation, condensation and purification EVAPORATION As liquid water molecules absorb energy from sunlight to allow them to break away from other water molecules entirely and enter the atmosphere. This process is known as evaporation and the result is water vapour – water molecules in the gaseous state. The amountt of water vapour in the air is humidity. Condensation is the opposite of evaporation. It occurs when water molecules rejoin to form liquid water. Condensation is greatly facilitated by aerosols in the  atmosphere. Aerosols are microscopic liquid or solid particles originating from land or solid surfaces. PURIFICATION When water in an ocean or lake evaporates, only the water molecules leave the surface and dissolved salts and other solids remain behind in solution. The water in the atmosphere turns over ever 10 days so the water is constantly being purified. PRECIPITATION Warm air rises from the earth’s surface. As it encounters the lower atmospheric pressure at increasing altitudes the air cools as it expands. As condensation intensifies, water droplets become large enough to fall as precipitation- hail , sleet, snow, rain. GROUNDWATER As precipitation hits the ground, it may either soak into the ground, infiltration or run off the surface (runoff).. All the land area that contributes to a particular stream or river is called the watershed for that stream or river. Water that infiltrates has two alternatives – some is held in the spaces between soil particles (capillary water) and returns to the atmosphere evaporation from the soil or through plants. (evapotranspiration). The second alternative is percolation. Infiltrating water is not held in the soil called gravitational water, because it trickles or percolates down through pores or cracks under the pull of gravity. This water accumulates and is called ground water. As water percolates through the soil, debris and bacteria from the surface are generally filtered out. However, the water may dissolve and leach out certain minerals. We have major problems in this area!!! WATER. A RESOURCE TO MANAGE, A THREAT TO CONTROL Human Impacts on the Water Cycle 1. Changes in the Earth’s surface – vegetation facilitates the infiltration of water into the soil and this is essential for the recharging of ground water (aquifers, springs and reservoir). As forests are cleared or land is overgrazed, the pathway of the water cycle is shifted from infiltration and groundwater runoff so the water runs into the streams and rivers almost immediately. This can cause floods and bring along sediments and other pollutants via surface erosion.  2. Climate change – groundwater is actually called fossil water. A warmer climate means more evaporation from land surfaces, plants, and water bodies because evaporation increases exponentially with temperature. 3. Atmospheric pollution – aerosol particles form nuclei for condensation. The more such particles there are, the greater is the tendency for clouds to form. Aerosols reduce solar radiation to the earth’s surface thereby causing a cooling effect. The unique feature of manmade aerosols is that they actually suppress rainfall where they occur in abundance even though they encourage cloud formation. With suppressed rainfall come drier conditions so more dust and smoke (aerosol) is the result. 4. Withdrawals of water for human use – water is withdrawn for consumptive use (irrigation and other agricultural use= 1) and non-consumptive use (electric power production = 2 , industrial use = 3 and residential use = 4). WATER POLLUTION Pollution – the Presence of a substance in the environment that because of its chemical composition or quantity, prevents the functioning of natural processes and produces undesirable environmental and health effects. Water pollution results from a host of human activity. There is a. Point sources- involve the discharge from factories, sewage systems, power plants, oil wells. b. Non-point sources- poorly defined and scattered abroad eg fertilizer run off Two basic strategies are used to control water pollution: a. Reduce or remove the source b. Treat the water and remove the pollutants or convert them to less harmless forms. The main pollutants include: a. Pathogens –the most serious pollutants which are infectious and can cause sickness and death. Some diseases include typhoid fever, cholera, Salmonella, hepatitis, and numerous parasitic diseases such as roundworms and flatworms. b. Organic wastes - human and animal wastes contain organic matter that creates serious problems if they enter our bodies untreated. As they decompose they can lead to depletion of oxygen in a water body. c. Chemical pollutants – water soluble inorganic chemicals include lead, mercury, cadmium, nickel and also acid rain pollute water. In addition, petroleum, pesticides, various industrial chemicals. d. Sediments - erosion from farmlands, deforested slopes, overgrazed range lands, mining sites, construction sites, and roads pollute water. This causes turbidity, reduces light penetration, prevents photosynthesis, clogs the gills of aquatic organisms. e. Nutrients- nutrients become water pollutants and stimulate undesirable plant growth in bodies of water. Sewage outfalls are especially culpable as is agricultural runoff. Biomagnification and Bioaccumulation Some chemical water pollutants are very dangerous to human health as they possess they capacity to biomagnify (increase in concentration of a pollutant from one link in a food chain to another) and Bioaccumulate (increase in concentration of a pollutant from the environment to the first organism in a food chain). This is of concern because together they mean that even small concentrations of chemicals in the environment can find their way into organisms in high enough dosages to cause problems. In order for biomagnification to occur, the pollutant must be: 1. long-lived 2. mobile 3. soluble in fats 4. biologically active If a pollutant is short-lived, it will be broken down before it can become dangerous. If it is not mobile, it will stay in one place and is unlikely to be taken up by organisms. If the pollutant is soluble in water it will be excreted by the organism. Pollutants that dissolve in fats, however, may be retained for a long time. It is traditional to measure the amount of pollutants in fatty tissues of organisms such as fish e.g. DDT EUTROPHICATION Introduction Benthic plants are aquatic plants which grow attached to, or are rooted in, the bottom of a body of water. They may be submerged or emergent and they need clear water so that light can penetrate and photosynthesis can occur. Increasing turbidity increases the depth at which they can survive. Phytoplanktons live suspended in water and are found wherever lights and nutrients are available. Low nutrients limit their growth. Considering the different requirements of phytoplankton and submerged aquatic vegetation SAV, the balance between them is altered when nutrient levels are changed. As long as water remains low in nutrients, populations of phytoplankton are suppressed, the water is clear and light may penetrate to support the growth of SAV. As nutrient levels increase, phytoplankton can grow prolifically making the water turbid, thus shading out the SAV. As nutrient levels in a water body increases 1. Rapid growth and multiplication of plankton increases the turbidity of water. 2. This shades out the SAV that live in water. 3. When they die there is loss of food, habitats and dissolved oxygen from photosynthesis 4. Phytoplankton multiplies rapidly settling to the bottom which results in heavy deposits of detritus on the lake or river bottom. 5. The abundance of detritus supports decomposing bacteria. These explosive growths of bacteria consume oxygen creating a biological oxygen demand. 6. The result is the suffocation of fish and shell fish. COMBATING EUTROPHICATION 1. Attack the symptoms a. Chemical treatments- use of herbicides to control the growth of nuisanance plants b. Aeration- the depletion of dissolved oxygen by decomposers and the consequent suffocation of aquatic life. Artificial aeration can avert this. c. Harvesting – harvesting the aquatic weeds may be a quick way to improve the water’s recreational potential and aesthestics 2. Getting to the root causes a. Controlling eutrophication requires long term strategies for correcting the problems and sediments. The first step is to identify the major point and non-point sources of nutrients and sediments. b. Good watershed management and erosion reduction strategies.\  INDICATOR SPECIES FOR WATER POLLUTION Usually it is the absence of the species which provides evidence of pollution. Some indicators are fish, invertebrates, periphyton, macrophytes. Indicator species for water pollution Biological indicators are unique environmental indicators as they offer a signal of the biological condition of water shed. Species which are sensitive to pollution in their habitat indicate the occurrence of pollution by their presence or absence. It is usually the absence of a species which provides evidence of pollution however; some are indicated by their presence eg Indian balsam grows where nutrient levels are high. Invertebrates can be good indicators to detect organic pollutants of water as lack of oxygen causes invertebrates to die. The major groups of indicators include: a. Fish – we need to know what kinds of fish are there, how many and their health which indicates the absence or presence of pollution. b. Invertebrates – aquatic invertebrates are food indicators because they are easy to collect, live in water for most of their life and stay in areas only suitable for their survival. c. Periphyton – benthic algae that grow attached to surfaces of rocks or larger plants. They are good indicators. d. Macrophytes – are aquatic plants and are good indictors because they respond readily to pollutants, do not require lab and analysis and are easily sampled. BIOLOGICAL OXYGEN DEMAND OF WATER (BOD) Dissolved oxygen is critical to the survival of fish and other flora. When excessive organic matter is present, decomposing bacteria break down these and during the process use up a lot of oxygen. Excessive decomposition of such organic matter leads to a depletion of oxygen in water. Natural organic wastes cause the death of fish because their decomposition uses up oxygen. This causes dissolved oxygen concentration to fall to critically low levels Nitrates and phosphates in a body of water also contribute to BOD. They cause plants to grow rapidly and when plants grow quickly they also die quickly and contributes to organic wastes in water which are decomposed by bacteria Temperature of water also contributes to high BOD levels. Warmer waters will have high BOD levels than cold water. As temperature increase the rate of photosynthesis or algae increases. Plants grow faster and die faster. Natural vs Cultural Eutrophication Natural eutrophication is a very slow process, and is somewhat temperature dependent. Cultural eutrophication happens when the amount of nutrients in the water and/or the water temperature are changed due to human activity, and the eutrophication process begins to run at high speed. Runoff from agriculture and from lawns, sewage disposal, erosion, and chemicals and waste heat from industry all are important contributors to cultural eutrophication Week 8 Agriculture and its Effects on the Environment Objectives 1. Trace the development and transformation of modern agriculture 2. Describe the consequences of crop farming and animal farming on the environment 3. Discuss the effects of subsistence farming on the environment. The Production and Distribution of Food The Development of Modern Industrialised Agriculture Until 150 years ago, many farms were small and utilised human and animal labour. Farmers used traditional approaches to combat pests and soil erosion such as: -crop rotation -Multi-cropping -use of animal wastes as manure In the mid 1800’s the Industrial Revolution had a major impact on farming, it raised the efficiency of farming. Crop production has increased remarkably due to the following: 1. Machinery – farm machinery handles every task which is performed on the farm and this has enabled the farmers to cultivate more land. However, this is dependent on the use of fossil fuel so as oil prices rise so does the cost of food. 2. Land under cultivation – globally, agriculture occupies 38% of the land and the net growth of lands has been constant at around 0.3% per year over the past years. This expansion comes at the expense of forests and wetlands which are both economically important and ecologically fragile. 3. Fertilizers and Pesticides – before farmers used animal manures as fertilisers however, between 1950 and 1990 world fertiliser use rose tenfold. When fertilisers levels are too high, the excess is washed away resulting in groundwater and surface water pollution. Chemical pesticide use has tripled since 1970 but the percentage of crops lost to pests has remained constant. This is because many pests build up resistance to chemical pesticides. Progress is being made toward developing natural means of control that are environmentally safe.  4. Irrigation – worldwide irrigation acreage has increased about 2.6 times from 1950-1980. Current irrigation is unsustainable as ground water resources are being depleted. Also, production is being adversely affected on 1/3 of the world’s irrigated land because of water logging and the accumulation of salts in the soil- consequence of irrigating where there is poor drainage. 5. High yielding varieties – scientists have now developed high yielding plants which give double or triple yields more than the traditional varieties.These varieties were introduced throughout the world, production soared and the Green Revolution was born. The technologies which gave rise to the agriculture revolution in the industrialised countries were eventually introduced into the developing countries and caused remarkable increases in crop production and is called the GREEN REVOLUTION. Animal farming and its consequences Quarter of the world’s croplands is used to feed animals. In the USA, 70% of grain crop goes to animal feeding. This is because a large number of the world’s population enjoy eating meat and dairy products. There are two patterns of animal rearing a. In large herds under factory like conditions (Factory-style farming of animals) b. Raised on family farms by subsistence farmers Factory Style Farming of Animals Industrial-style farming can affect the environment in many non-sustainable ways. This is because the majority of crops planted is fed to animals. So the crops have to be first planted, which caused five effects as outlined under crop farming then another five from animal farming so ANIMAL FARMING HAS A TOTAL OF 10 EFFECTS. Please remember this!!!!! a. Rangelands are susceptible to erosion b. Management of animal manure – in developing countries it is used to renew soil fertility, build shelters and provide fuel. In the developed countries it is a wasted resource. Approximately 1.3 billion tons of animal manure is produced each in the states alone - some of which is leaked into surface waters and contributes to the die off of fish, contamination with pathogens and proliferation of algae. The EPA asserts that animal-based agriculture is the most widespread source of pollution of the nation’s rivers. c. Loss of rain forests – in Latin America 49 million acres of tropical rain forests have been converted to pasture.This leads to loss of biodiversity. d. Climate change – ruminant animals eliminate 100 million tons of methane through belching and flatulence which contributes to the greenhouse effect. Anaerobic decomposition of manure adds another 30 million tons of methane per year. e. Also deforestation and other changes in land use in the tropics release an estimated 1.6 billion ton of carbon dioxide into the atmosphere contributing to the greenhouse effect.  Subsistence farming in the developed world In the developed world farmers continue to use the subsistence methods of farming. Subsistence farmers live on small parcels of land which provide them with food and hopefully a small cash crop. An estimated 1.4 billion people in Latin America, Asia and Africa depend on subsistence agriculture Environmental problems associated with subsistence agriculture 1. Woodlands are cleared for agriculture, firewood and animal feed. This causes the farmers to travel farther and farther from their homes into the forest and after cultivation, they leave the soil susceptible to erosion. 2. The ensuing scarcity of firewood lead the residents to burn animal dung for cooking and heating thus diverting valuable nutrients from the land. 3. Erosion prone land , suited to growing only grass or tress is planted to produce annual crops 4. Good land is forced to produce multiple crops instead of being left to fallow to recover nutrients. 5. Continued sub-division of the land diminishes the lands ability to support each household. All these practices tend to increase the poverty that is characteristic of populations supported by subsistence agriculture and the relentless cycle continues. The added poverty puts increased pressure on the land to produce food and income. Week 9 Biodiversity and wild species Objectives 1. State the importance of Forests , Oceans, Coral Reefs to the biosphere (HW) 2. Define fully the term biodiversity 3. Differentiate between intrinsic and instrumental value of wild species 4. Explain how wild species have value for agriculture , medicine and recreational value 5. Discuss the Value of Forests to Dominica Biodiversity Biodiversity is the numerous plants, animals and microbes that inhabit the biosphere. There are three types of diversity: a. Genetic diversity b. Species diversity c. Ecosystem diversity All ecosystems provide capital. The basis of the natural capital is the ecosystems and the basis of ecosystems is the plants, animals and microbes (wild species) that make them work. To maintain sustainability, their integrity must be preserved. We must protect wild species and the ecosystems where they live. The natural species of living things are responsible for the structure and maintenance of all ecosystems. They and the ecosystems the form represent biological wealth Biological wealth Species have two kinds of value a. Instrumental value – a species or organism has instrumental value if its existence benefits some other entity. b. Intrinsic value – something has intrinsic value when it has value for its own sake. It does not have to have value to be useful. Instrumental value (For Agriculture , Forestry, Aquaculture, Animal Husbandry) In nature, plants and animals are continually subject to natural selection. As a result, wild populations have numerous traits for competitiveness, resistance to parasites and tolerance to adverse conditions. Cultivated crops tend to lose these traits so plant breeders have to search wild relatives for the desired trait. Loss of biodiversity reduces these possibilities. (Sources for Medicine) Earth’s genetic bank also serves medicine. The rosy periwinkle of Madagascar contains the compounds vinblastine and vincristine which are used to treat leukemia and Hodgkin’s disease. The venom from the Brazilian pit viper (a poisonous snake) led to the development of the drug Capoten©. There are hundreds of plants with medicinal properties which are exploited in medicine such as aspirin, quinine, ipecac and codeine. Recreational Aesthetic and Scientific Value The species in natural ecosystems also provide the foundation for numerous recreational and aesthetic interests, ranging from hunting hiking, camping, bird watching. Interests under this head may range from casual aesthetic enjoyment to serious scientific study. Virtually all our knowledge and understanding of ecology and evolution have come from studying wild species and the ecosystems in which they live. Ecotourism is a very important source of revenue in some countries. Value for their own sake Instrumental value is apparent, but what of those species which have no obvious value to anyone? Some observers believe that the most important strategy for preserving all wild species is to emphasise the intrinsic value of species, rather than the unknown or uncertain ecological and economic instrumental values. The extinction of any species is an irretrievable loss of something of value. “Destroying species is like tearing pages out of an unread book, written in a language humans hardly know how to read, about the place where they live” – Holmes Ralston III. All species have a right to exist. Week 10 Biodiversity and Conservation Objectives 1. State the reasons for decline in biodiversity 2. Discuss the consequences of losing biodiversity 3. Differentiate between conservation and preservation 4. Outline different ways of conserving various resources 5. Identify the globally recognized organisations which protect endangered species 6. Explain how over use of a common can lead to destruction of the environment (Research) Biodiversity and its Decline Reasons for the decline 1. Physical alteration of habitats Although multiple causes are usually the rule in losses of biodiversity, one of the greatest sources of loss is the physical alteration of habitats through the process of conversion (to shopping malls, marinas, industrial centres), fragmentation and simplification (human use of habitats simplify them). 2. Pollution Pollution can directly kill many kinds of plants and animals, seriously reducing their populations. Everyday oil spills kill seabirds and, often, sea mammals, sometimes by the thousands. The recent and rapid rise in the incidence of these deformities is traced to habitats that have been altered by human use. 3. Climate change Global climate change is having a negative impact on many species. In the polar north bears are in decline because the sea ice they depend on for hunting seals is melting at a rapid rate. 4. Introduction of invasive species They can thrive, spread out and perhaps eliminate native species by predation or competition for space or food. They are the major agents of in driving native species to extinction 5. Overuse Removing whales, fish, or trees faster than they can reproduce will lead to their ultimate extinction. Overuse is driven by a combination of greed, ignorance and desperation. Consequences of losing biodiversity Biodiversity almost always refers to the diversity of species found in ecosystems. These are the structural components of the ecosystem. Identifying the structural components is important, because function flows from structure and it is the functioning ecosystem that provides the goods and services sustaining human life and enterprises. Read up on IUCN, CITES and CBD. https://www.youtube.com/watch?v=WZ8O498tcao https://www.youtube.com/watch?v=EQpZR53UACc https://www.youtube.com/watch?v=MXhrjff1zas https://www.youtube.com/watch?v=tMZo-bGBA5Y Week 11 Energy Objectives Solar, Wind, Hydro, Nuclear, Tidal, Geothermal, Biomass, Biofuel 1. Identify the three primary types of fossil fuel 2. Differentiate between a primary and a secondary energy source 3. Identify challenges facing countries which are dependent on imported fossil fuels 4. State ways of conserving energy 5. Describe the process of energy generation of a named form of alternative source of energy 6. State four (4) advantages and four (4) disadvantages of a named form of alternative source 7. State it applicability to Dominica 8. Support your choice of alternative energy sources for Dominica https://www.youtube.com/watch?v=ZLgOoMSlS3Y https://www.youtube.com/watch?v=q8HmRLCgDAI https://www.youtube.com/watch?v=qSWm_nprfqE https://www.youtube.com/watch?v=rcOFV4y5z8c https://www.youtube.com/watch?v=44ovdxOvP_A https://www.youtube.com/watch?v=Uv8bTAGr0tU https://www.youtube.com/watch?v=VkTRcTyDSyk https://www.youtube.com/watch?v=yHWcddUZ35s https://www.youtube.com/watch?v=ZGmwtDffc74 Fossil Fuels What are fossil fuels? Three fossil fuels, crude oil, coal and natural gas provide 75% of the worlds’ energy consumption. With fossil fuel energy, people and goods have become so mobile that the human community has become a global community (globalisation). ELECTRICAL POWER PRODUCTION A considerable portion of the total energy used by humans is electrical power called secondary energy source because it depends on a primary energy source (coal, waterpower or fossil fuel) to turn a generator. Over 33% of fossil fuel production is now used to generate electricity and this is not sustainable. Is electrical energy clean energy? Electrical power is often promoted as clean energy. Hidden however is the fact that pollution is simply transferred from one part of the environment to another. Coal burning power plants are the major source of electricity in developed countries as well as the major source of acid deposition (acid rain) because desulphurised coal is a dirty fuel. Declining US reserves and increasing importation Due to the low cost of oil in the 1970, industrialised nations were heavily dependent on crude oil. A group of Arab countries known as OPEC, formed a cartel and agreed to restrain production in order to get higher prices. In 1973 OPEC initiated an oil embargo on countries like the US and major shortages occurred and panic escalated. This was a serious eye opener and the US realised how another embargo can cripple the economy. In response to this, the United States did the following: a. it increased domestic production b. the country instituted guidelines decreased consumption of crude oil c. an underground oil reserve was created. The problem with the high dependency on oil in USA is disturbing because a. cost of purchase -extremely expensive commodity b. an unstable Middle East where most of the oil is found (Persian gulf oil, Saddam invaded Kuwait, Bush invaded Iraq ). c. limited resource and limitations may impact on us as production is decreasing FOSSIL FUELS AND ENERGY SECURITY Oil Dependence We increasingly depend on foreign oil. With OPEC and the unstable Middle Eastern countries our energy security is shaky and long term use of fossil fuel poses a risk to economic, environmental and national security due to climate change. CONSERVATION OF FOSSIL FUELS a. CAFE – corporate average fuel economy. Manufacturing and driving vehicles that give more miles per gallon b. energy saving appliances c. energy saving bulbs c. building to maximise natural light e. greater use of the internet for shopping etc Week 12 Atmospheric Pollution Objectives 1. Outline the structure of the atmosphere 2. State the important characteristics of the trophosphere and stratosphere 3. Differentiate between primary and secondary air pollutants/conventional and unconventional pollutants 4. State the major types of air pollutants and their sources 5. Discuss methane as an air pollutant 6. State the impacts of air pollution on human health and the environment 7. Outline ways on controlling air pollution Atmospheric Pollution The Atmosphere  The atmosphere is the vertical space above ground surface.  Consists of a thin layer of mixed gases covering the earth’s surface  Composition by volume 78% nitrogen 21% oxygen 1-3% water vapour 0.9 % argon 0.3% carbon dioxide SO2(g) The other major acidic oxide that contributes to the formation of acid rain is nitrogen dioxide. Nitric oxide is formed in high localised temperatures created by lightning strikes and naturally reacts in the atmosphere to produce nitrogen dioxide. Nitrogen dioxide is also produced in the high temperatures of combustion chambers of power stations and motor vehicles. Formation of Nitrogen Dioxide: N2(g) + 2O2(g) -> 2NO2(g) Both sulfur dioxide and nitrogen dioxide are acidic oxides and react with water to form acids. Sulfur dioxide reacts with water to form sulfurous acid. SO2 + H2O -> H2SO3 Substances in the upper atmosphere then catalyse the reaction between sulfurous acid and oxygen to form sulfuric acid. 2H2SO3 + O2(g) -> 2H2SO4 Recommended Online Texts can be obtained from the following open sources https://www.academia.edu/39209264/E.b.o.o.k_0076618943_Environmental_Science_A_Global_Concern_AP_Edition (for this you can sign up via Fb, you are undergrad , create a department (Natural Sciences) so you can proceed, you MUST SIGN UP TO ACCESS) https://healingearth.ijep.net/welcome https://libguides.furman.edu/oer/subject/earth-and-environmental-sciences