CONTENTSTITLEPAGE

INTRODUCTION1

CONCEPT MAP 2

HUMAN ACTIVITIES THAT ENDANGER AN ECOSYSTEM 3 - 19

THE GREENHOUSE EFFECT AND THE THINNING OF THE OZONE LAYER20 - 25

THE IMPORTANCE OF PROPER MANAGEMENT OF DEVELOPMENT ACTIVITIES AND THE ECOSYSTEM26- 29

CONCLUSION30

IntroductionNever before has the Earth been so threatened than it is today. The Earth has survived countless natural disasters such as volcanic eruptions and violent earthquakes, but even then, none of these catastrophes has had such a great impact on the Earth as the activities carried out by humans themselves.In their attempt to fulfil the growing needs of an ever-increasing population, mankind destroys natural habitats that house millions of flora and fauna species and at the same time pollutes the environment. Through this assignment, we shall see how human activities threaten the ecosystem and what we can do to minimise the impact of these activities.

Education on the management of resourcesPreservation and conservationThe use of renewable energyEfficient use of energyThe use of technologyImplementation of lawsBiological controlPower stationsVehiclesIndustriesDomestic wasteAgriculture wasteUntreated sewageHeavy metalsOil spillsCAUSESAirThermalNoiseWaterPollutionExtinctionDeforestationEutrophicationLandslidesFlash floodsSoil erosionENDANGERED ECOSYSTEMConcept Map

Steps to maintain a stable environmentGreenhouse effect and the thinning of the ozone layer.Impact of human activities, unplanned development and the mismanagement of ecosystems.

Human Activities that Endanger an Ecosystem

Human activities that threaten an ecosystem.

Human activities often affect whole ecosystems. Many of the problems related to the environment are the results of human activities and human interference with the ecosystems. The negative effects of hasty, unplanned development and the mismanagement of the ecosystems result in various environmental problems such as air and water pollution, the greenhouse effect, global warming and the depletion on natural resources.

Overuse of fertilizers in intensive farmingDeforestationBurning of fossil fuelsLeads toLeads toWater pollutionEutrophication Water pollutionDumping of domestic and industrial wasteLeads toLeads toThe greenhouse effectGlobal warmingAir pollutionSoil erosionLandslidesFlash floodsClimatic changesThe loss of biodiversityThe greenhouse effect and global warmingHuman activities that have undesirable effects on the environment

The impact of human activities on the ecosystem.

Deforestation and its effects. The rapid destruction of woodlands or the removal of trees from forests is known as deforestation.

Every year, vast areas of forests are cleared to make way for agriculture and development. Tropical rainforests have important ecological roles.(a) Rainforests are the oldest ecosystems on Earth and house almost half of the flora and fauna of the world.(b) They contain many unique species which provide food, medicine and other biological products. Plants from the tropical rainforests provide about one quarter of pharmaceutical products available today. According to the National Cancer Institute, 70% of the plants useful in the treatment of cancer can only be found in the tropical rainforests.(c) Rainforests regulate climate by influencing wind, rainfall, humidity and temperature patterns.(d) Rainforests are also called the carbon sink of the Earth because they absorb vast amounts of carbon dioxide during photosynthesis and at the same time release oxygen into the atmosphere.(e) They also serve as water catchment areas. Despite their importance, it has been estimated that more than 50 million acres of rainforests are destroyed or seriously degraded every year. In general, deforestation results in(a) soil erosion(b) flash floods(c) landslides(d) disruption to the carbon and nitrogen cycles(e) the loss of biodiversity

Deforestation causes soil erosion, landslides and flash floods.

LandslideFlash floodSoil erosion is the removal and thinning of the soil layer due to physical and climatic processes, such as high rainfalls.The absence of plant root systems makes the soil structure unstable.When there are heavy rains for a long period of time, the top layer of the soil crumbles and this leads to landslides on steep hillsides.The eroded soil is then carried by moving water and deposited at the bottom of rivers.This, together with the depletion of water catchment areas, causes flash floods during rainy seasons.Soil erosions causes the land to be depleted of minerals and natural resources, making the land infertile.

Deforestation disrupts the carbon and nitrogen cyclesDeforestation results in the loss of biodiversity.Deforestation has a devastating effect on the biodiversity in tropical rainforests. The destruction of millions of hectares of forests by human activities means; The removal of the bases of numerous food webs.The loss of habitats of many species of flora and faunaThe extinction of countless of species and varieties of plants and animals. The extinction of flora and fauna species reduces the biodiversity. Biodiversity can be a rich source of food and priceless medicines to mankind.The removal of plants in the rainforests disrupts the natural cycle of nutrientsThe level of atmospheric carbon dioxide rises as less carbon dioxide in the air is removed by plants during photosynthesis.The level of atmospheric oxygen drops as less oxygen us released by plants during photosynthesis.The recycling of nitrates and other ions slows down.Tree roots bind soil particles together, and the tree canopy reduces the force of rain beating down on the soil. Deforestation, therefore, causes the loss of nutrients through leaching and run-offs.

Deforestation disrupts the normal weather patterns, creating hotter, drier weather and causing global climatic changes.The removal of trees reduces transpiration, rainfall and the rate at which plants absorb carbon dioxide from the atmosphere during photosynthesis.This leads to an increase in the carbon dioxide in the atmosphere. High levels of carbon dioxide prevent heat from escaping the atmosphere. This known as the greenhouse effect which is believed to lead to global warming.Forest clearing and burning of wood result in air pollution and release more carbon dioxide.Burning of trees in the tropics adds about 25% more carbon dioxide to the atmosphere.Deforestation causes climatic changes

Burning of fossil fuels and its effects The burning of fossil fuels adds about 75% of carbon dioxide to the atmosphere. An increase in carbon dioxide level is associated with the greenhouse effect and global warming.

Intensive farming and it effects Excessive use of land and intensive farming decrease the space and resources available for other species. In intensive farming, farmers often use inorganic fertilizers, which contain nitrates, phosphates and potassium ions, to improve crop yields. Since nitrate and ammonium ions are highly soluble, they do not remain in the soil for long and are quickly leached into the surrounding rivers and lakes. This leads to eutrophication. Eutrophication is discussed later in the section on water pollution.

The effects of an increase in domestic waste and industrial waste An increase in human population generates an increase in both domestic and industrial waste. The dumping of waste in landfills poses a great danger to living organism as toxic substances and other pollutants from the dumpsites leak into the ground and eventually pollutes the nearby water sources.

Pollution

Pollution can be defined as any desirable change in the physical, chemical or biological characteristics of the natural environment. It is the result of harmful substances or energy released through human activities. There are four type of pollution: air, water, thermal and noise pollution.

Air pollution Burning of fossil fuels is the main source of air pollution. When fossil fuels are burnt, the elements in the fuels oxidised, forming various air pollutants. These include carbon dioxide (CO2), sulphur dioxide (SO2), oxides of nitrogen (NO2 and NO) and fine particulate matter.PollutantsSourcesEffectsSolutions

Carbon monoxide (CO) Colourless, odourless gas Incomplete combustion of fossil fuels The exhausts of vehicles factoriesHealth: Combines readily with haemoglobin and affects the transport of oxygen to body cells Impairs alertness, causes fatigue and headaches

Sulphur dioxide (SO2) Pungent, colourless gas Sulphur dioxide is formed when sulphuric compounds react with oxygen during combustion. Combustion of fossil fuels, particularly in hear and power generation facilities. Volcanic gases Large industrial boilers FactoriesHealth: Irritates eyes Damages respiratory passages Causes bronchitis Causes wheezing, a shortness of breath and coughing Causes asthmatic attacks

Climate: Combines with rainwater to form acid rainAgriculture: Contributes to acid rain which damages photosynthetic tissues Acid rain lowers pH of soil, rivers and lakesBuildings: Acid rain corrodes iron, limestone and stonework, and destroys buildings Use low sulphur content fuels Clean up emissions from power stations and factories with scrubbers

Oxides of nitrogen Nitrogen monoxide Nitrogen dioxideVehicle exhaustsAction of bacteria on fertilizersCombustion of fossil fuelsFactoriesHealth: Irritate lungs, nose, throat and eyes Cause respiratory infections Cause bronchitisClimate: Dissolves in rainwater to form acid rainAgriculture: Contributes to acid rain which lowers pH of soil, making it unsuitable for cultivation of crops Damages leaves and rootsBuildings: Acid rain corrodes metal and destroys stonework on buildingsClean up emissions from car exhausts by installing catalytic converters to turn oxides of nitrogen into harmless nitrogen gas.

Lead (Pb)Lead compounds are added to petrol to prevent the inefficient burning of the petrolair mixture Combustion of fossil fuels Vehicle exhausts fumesHealth: Retards metal development and damages the liver Can result in coma or deathUse unleaded petrol

Carbon dioxide (CO2) An acidic, colourless and odourless gas Open burning Combustion of fossil fuelsHealth: Affects respirationClimate: Leads to greenhouse effect and global warming Results in an increase in the atmospheric temperature Climatic changesReduce the use of fossil fuels.

Fine particulate matter A complex mixture of very fine liquid droplets or solid particles in the air, such as dust, smoke and exhaust fumes. Smoke contains tiny carbon particles called soot. Haze is formed when smoke, dirt and particulate matter combine with water vapour in the atmosphere. When there is no wind, smoke may be trapped by fog to form smog. Incomplete combustion of fossil fuels, for example, bonfires, open burning, the burning of oil wells and the burning of dried paddy stalks. Motorised vehicles (exhaust fumes) Quarries, sawmills and asbestos factoriesHealth: Irritate the eyes, nose and lungs Damage the respiratory passages and lungs Haze can cause conjuctivities, sore throats, influenza, asthma and lead to bronchitis. Dust from quarries, sawmills and asbestos factories can cause lung diseases. Haze leads to reduce visibility.Agriculture: Smoke particles (soot) deposit on leaves and block stomata. This prevents gaseous exchange. Both lower the photosynthetic rate of plants which subsequently reduces crop yields.Climate: Contribute to the formation of haze and smog. Smoke and haze can reduce visibility.Buildings: Soot darkens buildings More efficient burning of fuels in well-designed furnaces. Stop open burning

Acid rain Causes of acid rain(a) Combustion of fossil fuels (coal, air and gas) in power station, factories, domestic boilers and internal combustion engines releases large quantities of sulphur dioxide (SO2) and oxides of nitrogen (NO and NO2)(b) Sulphur dioxide and oxides of nitrogen combine with water vapour in the atmosphere to form sulphuric acid and nitric acid respectively. Then they fall to Earth as acid rain. Causes of acid rain(a) Agriculture: The soil becomes acidic and unsuitable for the cultivation of crops Acid rain causes the leaching of minerals such as potassium, calcium and magnesium. Photosynthetic tissues are destroyed. (b) Aquatic ecosystem: Acid rain causes insoluble aluminium ions to accumulate in lakes and rivers. The concentration of aluminium ions eventually reaches a toxic level which can kill aquatic organisms such as fish and invertebrates. Increased acidity in the aquatic ecosystems also kills phytoplankton which changes the food chain.(c) Health: Acidic soil releases the ions of certain heavy metals such as cadmium, lead and mercury which may contaminate the supply of drinking water.(d) Buildings: Metal railings and bridges corrode. Limestone, stonework and marble monuments are eroded due to chemical weathering. Acid rain can be reduced by(a) Cleaning up emissions from power stations and industrial plants with scrubbers. This process involves the spraying of water to trap pollutants.(b) Cleaning up emissions from vehicle exhausts through the use of catalytic converters. The pollutants react with one another in the catalytic converters to produce less harmful products.

Water pollution Water sources are the most easily polluted as they are most affected by human activities. Industrial, domestic and agricultural activities produce waste which pollutes water.SourcesPollutants Effects

Industrial factories Heavy metals such as mercury, zinc and lead Radioactive waste Most of them are toxic May cause cancer and leukaemia if they accumulate in the human body The pollutants can be passed on through food chains

Agriculture Phosphate and nitrate in fertilisers Herbicides and pesticides Eutrophication is the enrichment of nutrients in the sources of water that promotes the growth of algae on the surface of the water and thus prevents sunlight from entering the water. Submerged plants will die and will be decomposed by bacteria causing the oxygen in the water to decrease. Consequently, the BOD increases and aquatic organisms will die. Pesticides are toxic and are passed on through the food chains to humans.

Livestock farming Animal faeces contains bacteria Cause diseases such as typhoid fever, cholera and skin diseases

Domestic sewage Non-biodegradable materials such as plastic, glass and aluminium Blocks the flow of water and causes stagnant water Becomes breeding grounds for mosquitoes and causes the spread of diseases such as dengue fever and malaria

Ship tank Oil spill Causes the death of sea birds and fish Blocks the exchange of respiratory gases

Eutrophication Draining the excess nutrients into ponds, lakes or river encourages the rapid growth photosynthesizing organisms, especially algae. This results in a population explosion known as an algal bloom.The excessive growth of algae restricts the penetration of light into the water. As a result, the photosynthesis of other aquatic plants is greatly reduced and this further decreases the supply of oxygen in the water.The algae grow faster than their consumers. As a result, most of the algae die without being consumed.The process and consequences of eutrophication

The low level of oxygen concentration kills larger aerobic aquatic organisms. Organisms that require high oxygen levels will not survive.In extreme cases, if the oxygen level continues to drop and the water becomes completely deoxygenated, aerobic bacteria will grow and release toxic gases, causing the death of many aquatic organisms,During the growth of algae, certain blue-green bacteria also produce toxins that may cause the death of fish.At high B.O.D levels, organisms that are more tolerant of lower concentrations of dissolved oxygen may appear and multiply.As the photosynthetic organisms die and organic material accumulates at the bottom of the lake, decomposing microorganisms, especially aerobic bacteria, grow rapidly and use up oxygen in the deeper waters at a fast rate.The aerobic bacteria use up oxygen faster than it can be replenished. An increase in the biochemical oxygen demand (D.O.B) causes the oxygen levels to decrease rapidly.

Thermal pollution Effects of thermal pollutionWater temperature can affect the level of dissolved oxygen. When the temperature of water increases, oxygen becomes less soluble in water.(a) For some species, a sudden increase in temperature can lead to instant death because many aquatic species can only survive within a certain range of temperature.(b) The death of these species may have a negative effect on the food chain, causing the entire ecosystem to collapse.3. If the temperature increases continues for a long period of time this may result in permanent changes in the species composition of the aquatic ecosystemThermal pollution occurs due to excessive loss of heat to the environment

Causes of thermal pollutionHot water is discharged into nearby lakes and rivers from the effluents of industrial processes and the cooling towers of electrical power stations which use water as a cooling agent.The excess heat that is released into the environment leads to thermal pollution.Thermal pollution causes the temperature in a body of water to rise above the normal value. The increase in temperature can be between 5C and 10C.

Control the amount of hot water discharged from industrial plants and power stations.Ways to prevent thermal pollution

Noise pollution Noise pollution is caused by motor vehicles, agricultural machinery, industrial machinery and work at construction sites Continuous exposure to loud sounds and more than 80 decibles (dB) in the long term can cause deafness Extreme noise can also cause stress related problems such as high blood pressure, heart attacks, depression and headaches.

THE GREENHOUSE EFFECT AND THE THINNING OF OZONE LAYER

The greenhouse effect. The greenhouse effect is an effect in the atmosphere as a result of the presence of certain gases, called the greenhouse gases. Greenhouse gases in the atmosphere are similar to the glass panes of a greenhouse which trap the heat and warm the greenhouse. Carbon dioxide, chlorofluorocarbons (CFCs), methane, nitrous oxide, low level ozone and water vapour make up the greenhouse gases.

Scientists believe that the combustion of fossil fuels and other human activities such as increased deforestation and industrial production are the primary reasons for the increased concentrations of atmospheric carbon dioxide. As the concentration of greenhouse gases rises, trapping more heat in the atmosphere and raising the average temperature on Earth. This overall rise in the average temperature of the atmosphere is known as global warming. Over the last 40 years, the average temperature on Earth has increased by about 0.2-0.3C. In Malaysia, temperatures have been rising at 0.18C every decade. Without emission control policies, it is projected that carbon dioxide concentrations will be 30% - 150% higher than the present level. The average temperature on Earth may rise between 1.5C and 4.5C by 2100.

THE THINNINGOF OZONE LAYER

The ozone layer is a region in the stratosphere, between 20 and 25 kilometers above the surface of the Earth The ozone layer filters out UV radiationA satellite image of the ozone holes over the Antarctica. The dark region in the image is actually an ozone hole.The ozone layer contains high concentrations of ozone molecules (O3) that absorb ultraviolet (UV) radiation and shield organisms from its damaging effects

The thinning of the ozone layer has been recorded by scientists since the 1970s. In 1985, it was reported tjat the stratos[heric ozone over the Antartica had declined by 40% since 1977. The atmosphere in this area has very low ozone concentrations, resulting in the formatin of an ozone hole. An ozone hole has now appear above the Arctic as well. Consequently, UV radiation has risen by 7% per decade in the northern hemisphere and by 10% per decade in the southern hemisphere. This later of ozone shields us from excessive ultraviolet radiation from the sun.

THE IMPORTANCE OF PROPER MANAGEMENT OF DEVELOPMENT ACTIVITIES AND THE ECOSYSTEM

The need for development and the effects of an increasing population on the ecosystem. As the population of the world increases, so do the needs of this population. The need for more food supplies, homes, education, and medicine, water, and transport systems has led deforestation, the burning of fossil fuels, the building of more dams and reservoirs, and the production of more domestic and industrial The development projects have led to frequent human interference with the balance of nature. The negative effects of unplanned development are various environmental problems. In order to reduce the negative effects of developments, every economic activity or development project must be balanced by efforts to manage the environment in a sustainable manner.

Measures taken in the management of development activities. Implementation of laws(a) The Malaysian government has implemented acts and laws to protect the quality ofthe environment.(b) Examples: The Environmental Quality Act, 1974, 1985 (amendment) and National Forestry Act, 1984.(c) Regulation for disposal of crude palm oil waste in water (Crude Palm Oil Regulations, 1977)(d) Regulation for industrial and domestic wastedisposal(Sewage and Industrial Effluents Regulations, 1979)

Use of technology(a) Use Biotechnology, special bacteria can be produced to break down the oil layerfrom an oil spill in the sea.(b) Exhaust gases are passed through catalytic converters to reduce the amount of carbon monoxide and oxides of nitrogen emitted from the exhaust pipes.(c) Filters are fixed on chimneys to reduce the release of toxic gases.(d) Unleaded petrol, natural gas and alcohol canbe used to replace leaded petrol for vehicles.(e) Treatsewageinsewagetreatmentplantsand treat toxic waste from factories before it is discharged so as to reduce water pollution.(f) Organic waste from agriculture canbe processed into methane for fuel.

Education on the management of resources The public must be educated on theimportance of protecting and caring for the environment through the mass media andvarious environment campaigns. The public must be educated on the concept of the4Rs.The4Rsstandforrecycle,reuse, reduce, renew.(a) Recycle collecting and segregating waste materials according to their types and turning these waste materials into newproducts.(b) Reuse things such as old plastics, containers, and bottles instead of throwing them away.(c) Reduce the use of materials. (d) Renew the useof materials such as bottlesand plastic containers after they are clean

Preservation and conservation of the soil, water, flora and fauna of forests and mangrove swamps.(a) Conservation and preservation of land will decrease leaching and soil erosion.(b) Practice crop rotation, planting, of cover crops, controlled grazing, contour ploughing, terracing, use of synthetic and natural fertilizers to fertilize the soil and practice strip cultivation.(c) Water sources must be preserved and not use as dumping sites for domestic and toxic waste which can pollute the water.(d) Natural habitats will perish; animals and plants will be endangered when there is no control on human activities such as deforestation for development, agriculture and industry.(e) Replanting programs ensure that the trees which have been cut down by logging activities are replaced with new trees so that the forest will continue to productive and we able to support lives.(f) Minimize damage to the environment when building an infrastructure.(g) Laws should be implemented to punish the people involved in illegal logging activities.(h) Clearing of mangrove swamps for timber and agriculture robs the flora and fauna of their habitats. Effort must be made to conserve these mangrove swamps to maintain ecological balance.

The practice of biological control.(a) Biological control is an alternative method of controlling pests. It involves the use of natural predators to reduce the population of pests.(b) It is effective and will not pollute the environmentCONCLUSIONHuman activities often have a widespread impact on ecosystems. With greater advances in medicine, modern farming techniques and better infrastructure, the worlds population has grown to over six billion today. Conflicts therefore arise between fulfilling immediate human needs and the necessity to protect the environment from long-term damage.It is obvious that we cannot continue to pollute the Earth without facing consequences. Our demands for resources have to be balance with the need to sustain the resources themselves. A small effort on our part will go a long way to create a cleaner and healthier living environment. Hopefully, we will all soon realize that the sooner we act, the longer the Earth will live.

2