NAME : SIVARAJAN A/L GOPALAKRISHNAN

I/C NOMBER : 960621-02-5517

CLASS : 4 BERSIH

Teacher’s Name : CIK NGANG

iNTRODUCTION

oBJECTIVE

Human Activities That Endanger The Ecosystems

A)Deforestation

1.Rapid destruction of woodlands or removal or trees from the forest are known as deforestation.

2.Mostly this occurs when people want to do agriculture and development at the place.

Causes > -soil erosion -landslides -flash floods -climatic changes -the loss of biodiversity -the greenhouse effect and global warming

Effects > a)Dodo,shown here in a 1651 illustration by Jan Savery, is an often-cited example of modern extinction. b)The Golden Toad was last seen onMay 15,1989.Decline in amphibian populations is ongoing worldwide.P icture of  d is forestat ion

Modern extinctions/Main article: Holocene extinction/Further information:Deforestation The Holocene extinction refers to the extinction ofspecies during the present Holocene epoch (since around 10,000 BC). The large number of extinctions span numerous families of plants and animals includingmammals, birds, amphibians, reptiles and arthropods. Although 875 extinctions occurring between 1500 and 2009 have been documented by the International Union for Conservation of Nature and Natural Resources,[1] the vast majority are undocumented. According to the species-area theory and based on upper-bound estimating, up to 140,000 species per year may be the present rate of extinction.[2]

The Holocene extinction includes the disappearance of large mammals known as megafauna, starting between 9,000 and 13,000 years ago, the end of the last Ice Age. 

B)Burning Of Fossil Fuels 1.The burning of fossil fuels adds about 75% of carbon dioxide to the atmosphere.

2.An increase in carbon dioxide level is associated with the greenhouse effect and global warming. Causes > - the unlimited factories excess the smoke to surroundings. -vehicles release carbon monoxide.

Effects >

burning fossil fuels has a direct impact on the solar radiation reflectivity of clouds, thereby contributing to global climate change.

Main Article :ScienceDaily (Jan. 19, 2004) — Atmospheric researchers have provided observational evidence that burning fossil fuels has a direct impact on the solar radiation reflectivity of clouds, thereby contributing to global climate change. Joyce Penner, professor in the University of Michigan Department of Atmospheric, Oceanic and Space Sciences, U-M graduate student Yang Chen, and assistant professor Xiquan Dong from the University of North Dakota Department of Atmospheric Science, reported their findings in the Jan. 15 issue of the journal Nature.Most evidence that increased levels of fossil fuel particles (aerosols) affects the reflectivity of clouds, thereby producing a cooling effect on the climate, has been indirect. "This made it difficult to determine the impact this phenomena, known as the indirect aerosol effect, has on the global climate," Penner said. "Our data makes the direct connection and opens new areas of study."Solar radiation, which adds to global warming, is reflected back into space by clouds. Cloud droplets are increased with higher levels of aerosols, allowing for less radiation, or heat, to reach the lower atmosphere. The end result is a measurable cooling effect on the climate.Using atmospheric data gathered from a site in Oklahoma, a typical continental site with a high concentration of aerosols, and a typical Arctic site in Barrow Alaska with low aerosol concentration, the researchers were able to show that the difference in cloud reflectivity at the two sites was caused by the difference in aerosol levels. The researchers also provided important evidence that the computer simulation model used in the study was capable of

estimating cloud optical properties determined over a broad range of aerosol concentrations."This study is important for two reasons," Penner said. "First, it provides evidence that there is some cooling of the climate due to anthropogenic aerosols. Second, the simulation model we used has been shown to be a valuable tool in determining more directly the impact of aerosols on the climate."Penner cautioned that over longer time scales in the future, the climate cooling due to the indirect aerosol effect will be minimal when compared to the climate warming of carbon dioxide. "We've shown that there's more work to be done to discover all of the various ways we affect the climate." http://aoss.engin.umich.edu/ andhttp://www.nature.com/

PollutionTypes Of Pollution :-

a) Air Pollution

b) Water Pollution

c) Soil Pollution

d) Noise Pollution

a)Air pollution

The introduction of   chemicals ,   particulate matter , or 

biological materials   that cause harm or discomfort to humans or other living organisms, or damages thenatural environment into the atmosphere.  The atmosphere is a complex dynamic natural gaseous system that is essential to support life on planet Earth. Stratospheric ozone depletion due to air pollution

has long been recognized as a threat to human health as well as to the Earth's ecosystems. 

Air pollution from  World War II   production .

Sulfuroxides (SOx) - especially sulfur dioxide, a chemical compound with the formula SO2.SO2is produced by volcanoes and in various industrial processes. Since coal and petroleum often contain sulfur compounds, their combustion generates sulfur dioxide. Further oxidation of SO2, usually in the presence of a catalyst such as NO2, forms H2 SO4, and thus acid rain. This is one of the causes for concern over the environmental impact of the use of these fuels as power sources.

 Nitrogenoxides   (NOx) - especially  nitrogen dioxide   are emitted from high temperature combustion. Can be seen as the brown haze dome above or  plume   downwind of cities. Nitrogen dioxide is the chemical compound with the formula NO2. It is one of the several nitrogen oxides. This reddish-brown toxic gas has a characteristic sharp, biting odor. NO2

Is one of the most prominent air pollutants.

 Carbonmonoxide   - is a colourless, odourless, non-irritating but very poisonous gas. It is a product by incomplete combustion of fuel such as natural gas, coal or

wood. Vehicular exhaust is a major source of carbon monoxide.

 Carbon dioxide   (CO2)- a  greenhouse gas   emitted from combustion but is also a gas vital to living organisms . It is a natural gas in the atmosphere.

 

Volatileorganic compounds   - VOCs are an important outdoor air pollutant. In this field theyare often divided into the separate categories of methane (CH4) and non-methane(NMVOCs). Methane is an extremely efficient greenhouse gas which contributes to enhanced global warming. Other hydrocarbon VOCs are also significant greenhouse gases via their role in creating ozone and in prolonging the life of methane in the atmosphere,although the effect varies depending on local air quality. Within the NMVOCs, the aromatic compounds benzene, toluene and xylene are suspected carcinogens and may lead toleukemia through prolonged exposure. 1,3-butadiene is another dangerous compound which is often associated with industrial uses.

 Particulate matter   - Particulates, alternatively referred to as particulate matter (PM) or fineparticles, are tiny

particles of solid or liquid suspended in a gas. In contrast, aerosol refers toparticles and the gas together. Sources of particulate matter can be man made or natural.Some particulates occur naturally, originating from volcanoes, dust storms, forest andgrassland fires, living vegetation, and sea spray. Human activities, such as the burning of fossil fuels in vehicles, power plants and various industrial processes also generate significant amounts of aerosols. Averaged over the globe, anthropogenic aerosolsThose made by human activitiescurrently account for about 10 percent of the total amount of aerosols in our atmosphere. Increased levels of fine particles in the air are linked to health hazards such as heart disease, altered lung function and lung cancer.

 Persistent free radicals   connected to airborne fine particles could cause cardiopulmonary disease.

 Toxic  metals , such as  lead ,   cadmium   and  copper .  

 

Chlorofluorocarbons   (CFCs) - harmful to the  ozone layer   emitted from products currently banned from use.

 Ammonia   (NH3) - Emitted from agricultural processes. Ammonia is a compound with the formula NH3

. It is normally encountered as a gas with a characteristic pungent odor.Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to foodstuffs and fertilizers. Ammonia, either directly or indirectly, is also a building block for the synthesis of many pharmaceuticals. Although in wide use, ammonia is both caustic and hazardous.

[Source: The New York Times, February 19, 1989.]

b)Water pollution

- Boston Harbor is a strong example of how badly pollution can damage bodies of water. The water is filled with toxic waste and sewage, and routinely receives more waste when rainfall pushes it into the harbor.

- Many bodies of water near urban areas are highly polluted.This is the result of both garbage dumped by individuals and dangerous chemicals legally or illegally dumped by industries.

- The main problem caused by water pollution is that it kills life that inhabits water-based ecosystems. Dead fish, birds,dolphins, and many other animals often wind up on beaches,killed by pollutants in their habitat.

- Pollution disrupts the natural food chain as well. Pollutants such as lead and cadmium are eaten by tiny animals. Later,these animals are consumed by fish and shellfish, and the food chain continues to be disrupted at all higher levels.

- Eventually, humans are affected by this process as well.People can get diseases such as hepatitis by eating seafood thathas been poisoned.

- Ecosystems can be severely changed or destroyed by water  pollution. Many areas are now being affected by careless human pollution, and this pollution is coming back to hurt humans

Odors   —

- such as from garbage, sewage, and industrial processes

 

c)Soil pollution

- Not enough oxygen in the soil,

- acidy soils that may burn the plant, 45 

- bugs will go and start an infestation in thesoil,

it effects plants growth,

- the soil pollution eats away at thenutrients and becomes

- a bigger soil polluter,

- not enough drainage,

- new soil diseases develop every year,

- not enough moisture in the soil.

d)Noise Pollution

- Noise pollution disturbs our health and behavior in a number of ways including deafness causing lack of sleep, irritability, indigestion, heartburn, high blood pressure, ulcers, and heart disease. Just one noise explosion from a passing truck drastically alters our endocrinal, neurological, and cardiovascular functions in many individuals. If this is prolonged or frequent,the physiological disturbances become chronic and contribute to mental illness.

- Sometimes, even low levels of noise are irritating and can be frustrating, and high volumes can be annoying.Natural sounds are less irritating than those we find uncontrollable but intermittent sounds such as a tap dripping water can be more irritating than the sound of falling rain.

- Noise more than 50dB can be very difficult to hear and interpret and cause problems such as partial deafness.

- Increased noise levels gives rise to a lack of concentration and accuracy at work, and reduce one’s productivity and performance. Difficult tasks can be impaired, and instructions or warnings difficult to be heard and interpreted, causing accidents.

The Greenhouse Effects and the   Thinni ng of the   Ozone Layer

Greenhouse effects >- Occur when greenhouse gases accumulates

in the atmosphere to form a layer of gases

- Greenhouse gases – carbon dioxide,chlorofluorocarbon, nitrogen oxides,methane and water vapour

- The layer of gases trap the Sun’s heat around the world Greenhouse effect cause the global warming

48

 

Ozone layer >

- located in the atmosphere.

- consist of ozone molecules which made up of three oxygen atom (O3).

- act as protective shield that absorb the Sun’s harmful UV radiation

 

Thinning of ozone layer >

- Main cause - chlorofluorocarbon (CFC)

- CFC – man made gases used as refrigerant (substance that make things cold or freeze) and propellants(compressed gas that forces out the content of an aerosol container)

- CFC when exposed to UV radiation will release chlorine atom which can break down ozone molecules in chain reaction causing the ozone layer become thinner.

Steps to Maintain A Stable Enviroment

Ground level ozone   (O3)

formed from NOx and VOCs. Ozone (O3) is a key constituent of the troposphere (it is also an important constituent of certain regions of the stratosphere commonly known as the Ozone layer). Photochemical and chemical reactions involving it drive many of the chemical processes that occur in the atmosphere by day and by night. At abnormally high concentrations brought about by human activities (largely the combustion of fossil fuel), it is a pollutant, and a constituent of smog.

 Peroxyacetyl nitrate   (PAN) - similarly formed from NOx and VOCs.Minor air pollutants include:

 A large number of minor  hazardous air pollutants .  

 A variety of   persistent organic pollutants , which can attach to particulate matter. Persistent organic pollutants (POPs) are organic compounds that are resistant to environmental degradation through chemical, biological, and photolytic processes. Because of this, they have been observed to persist in the environment, to be capable of long-range transport, bio accumulate inhuman and animal tissue, bio magnify in food

chains, and to have potential significant impacts on human health and the environment.  

CONCLUSION :

REFERENCE :

Resources:

Biology text book form 4Biology text book form 4(pg292-294)

http://library.thinkquest.org/Chttp://library.thinkquest.org/C0127068/deforestation.html0127068/deforestation