P6 Man and Impact on Environment Notes

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P6 Man and Impact on Environment Notes

1. Negative and Positive Impacts

As man interacts with his environment, his actions may leave a positive or negative

impact on the environment.

Negative impacts include pollution, deforestation, global warming and depletion of

the ozone layer.

However, man can take steps to reduce the negative impacts through conservation of

resources, recycling, reforestation and responsible use of plastics and chemicals.

These actions will leave a positive impact on the environment.

There is an urgent need for man to conserve the environment before the negative

impacts destroy our earth and make it a very unpleasant place to live in.

2. Pollution

There are many forms of pollution, such as land, water, air and noise pollution.

a) Land Pollution

Irresponsible dumping of rubbish results in land being polluted. Rotting rubbish

gives off a bad smell and breeds germs. Piles of rubbish also take up space and are

unsightly.

Leakage of nuclear waste from nuclear reactors or industrial chemicals from

factories may also pollute the land. Such leakages are very toxic and harmful to living

things. They may cause birth defects, strange diseases and even death.

Mining of metals from the earth results in large amounts of soil being dug up and

dumped elsewhere. The resulting holes left by mining make the land unsuitable for

many uses




b) Water Pollution

Seas and oceans may be polluted by oil spills from ships. The layer of oil is toxic to marine

life. Oil may also stick to the feathers of birds, making them unable to fly, hunt fish

or escape predators.

Rivers and lakes may be polluted by the excessive use of insecticides, weedkillers and

fertilizers on farms. These chemicals are washed off when it rains, and the surface run-

off

flows into the water bodies.

- Insecticides and weedkillers may kill marine life.

- Fertilizers, however, may encourage algae growth. An overgrowth of algae covers

the surfaces of ponds and lakes. This blocks sunlight from reaching other

water plants. As a result, these plants cannot photosynthesize and will die.

Marine animals depending on these plants for food will also die.

Untreated chemical waste or hot water discharged by factories into water bodies may kill or harm marine life.

Untreated sewage is toxic to marine life and can also encourage algae growth.




Air Pollution

Burning any object releases carbon dioxide and soot into the air.

—Many things are burnt daily. Fossil fuels are burnt to

generate electricity and to supply power to vehicles.

—Rubbish is incinerated.

—Trees are burnt in the "slash and burn" method of clearing forests to make way for

plantations.

The pollutants released into the air may cause breathing difficulties and also result in haze

forming.

Under certain weather conditions, factory pollutants may be trapped in the air near the

ground, forming a thick, yellow smog. This causes breathing difficulties and may even

result in death.

In addition, burning of fossil fuels releases sulphur dioxide and nitrogen dioxide. When

sulphur dioxide and nitrogen dioxide dissolve in rainwater, they form acids, which then

fall as acid rain.

—Acid rain is corrosive and can damage buildings and stone monuments.

—Acid rain may also damage plants.

—If acid rain collects in lakes, it can kill marine life.




d) Noise Pollution

Heavy construction machinery such as pneumatic drills, piling

machines and sledge hammers generate loud noises.

Engines of machines and vehicles can also be very noisy.

Loud music blasting from a radio also contributes to noise pollution.

Long term exposure to very loud sounds can damage our eardrums and result in a

partial or complete loss of hearing.

3. Deforestation

Deforestation occurs when a large number of trees are chopped down for various

reasons.

—Trees may be chopped down to produce paper.

—Wood may also be used in construction or making furniture.

—Forests may be cleared to make way for building projects or plantations.

As the trees are removed, there is less shelter to protect the ground from the impact of

rainwater.

There are also less roots to hold on to the soil. This results in large amounts of soil

being washed away during heavy rains, thus causing landslides.

As the soil is washed into water bodies, it causes the water to become murky or

"turbid". This prevents sunlight from reaching the marine plants, and reduces the rate

of photosynthesis.

Plants take in carbon dioxide and give out oxygen during photosynthesis. In this way,

they help to recycle our air and produce oxygen for all other living things.

Deforestation reduces the number of plants in the area, resulting in less oxygen being

produced. The carbon dioxide level in the air will also rise.

The natural habitat of many animals is also destroyed, resulting in many species

becoming endangered or extinct.




Plants with useful medicinal values may also be destroyed as a result of deforestation.

4. Global Warming

"Global warming" refers to the rise in average temperatures across the world.

It is caused by an increase in carbon dioxide levels due to large scale burning and

deforestation.

Heat from the Sun is trapped by a layer of carbon dioxide and greenhouse gases in

the atmosphere. The heat is unable to escape to outer space and is reflected back to

earth. This results in a rise in temperature on earth.

The effect of carbon dioxide trapping heat is similar to that of glass trapping heat in a

greenhouse. Thus, this effect is known as the "Greenhouse effect".

Global warming causes the polar ice caps to melt. This results in a rise in sea level

and the flooding of lowlands and coastal areas.




Livestock, crops and property are destroyed as a result.

The habitat of animals living in the North and South Poles are also destroyed.

Plants and animals which cannot adapt to the increase intemperature will also rise

5. Depletion of the Ozone Layer

The ozone layer is a layer of ozone gas in the earth's atmosphere.

It limits the amount of ultra-violet (UV) rays from the Sun entering the earth.

However, excessive use of chlorofluorocarbons (CFCs) has damaged the ozone

layer, causing it to be depleted. In some areas, the ozone layer is so thin that a "hole"

is forming. CFCs are found in some aerosol sprays, refrigerators

and insecticides.




CFCs are also used in manufacturing some plastics and styrofoam. The CFCs

may be released into the atmosphere when plastics and styrofoam are burnt.

As the ozone layer gets depleted, more UV rays can enter the earth.

UV rays carry heat energy and cause the earth to heat up. This contributes to global

warming.

Excessive exposure to UV rays can also cause skin cancer and harm our eyes.

6. Conservation

Some of our natural resources, such as fossil fuels and metals are non-renewable.

Fossil fuels will take billions of years to be replaced by nature once they are

used up.

Metals which are mined from the earth's crust cannot be replaced once they are

used up.

In order to conserve fossil fuels and reduce pollution caused by burning them, Man can

switch to using other renewable sources of energy such as solar power, wind or

water to generate electricity.

As metal can be easily melted down and reshaped, scrap metal

can be recycled to reduce the need to mine more metals.

Man can also set aside forests as nature reserves to protect the plants and animals

living within it from being destroyed by deforestation.

7. Reduce, Reuse and Recycle

The use of disposable items such as plastic cutlery and disposable chopstick

contributes to the amount of rubbish generated.




Not only does producing these items deplete our natural resources, disposing them can

also cause pollution, as mentioned above.

We can reduce the waste that is generated by reusing or recycling some of these items.

Items made from glass, metal or paper may also be recycled to conserve our natural

resources.

7. Reforestation

To reduce the impact of deforestation, man can plant new trees to reforest an area.

Man can plant trees specifically for making paper or other wood products instead of

chopping down large forests. These trees are known as "farmed trees".

Industries which generate a lot of carbon dioxide through the burning of fossil fuels (such

as the airline industry) can also set aside a sum of money to plant trees and reduce the

amount of carbon dioxide generated. This is known as "reducing the carbon

footprint".




8. Man’s Positive Impact on the Environment

Man-made materials, sometimes known as synthetic materials, reduce our dependency on natural resources. The diagram below shows how some man-made materials are created:

These includes alloys, plastics and ceramics.

Alloys are formed by mixing metals with other substances (metal and non-metal). They are stronger and harder than pure metals. Steel, which is an alloy of iron and carbon, is stronger than iron. It has properties like being more corrosion resistant which are useful.

Plastics offer qualities not found in any of today’s pulp-based papers such as being tear-resistant, washable, durable and scratch resistant.

Ceramics are useful in microelectronics and structural composites components.

Thus, many man-made materials have replaced many natural materials, helping to preserve and protect our natural environment. However, many of the man-made materials are non-biodegradable, and in other words, they do not decay. Burning them might also produce poisonous gases like burning plastic. This adds to the amount of waste and occupies much space.

9. Development in Science and Technology

We use whatever natural resources we can find around us to satisfy our basic needs. As we interact with our environment, we continually discover new ways to make our lives easier and better. In this interaction with the environment, we develop areas such as biotechnology and telecommunications. Biotechnology is any technique that uses living organisms to make products or provide services that benefit mankind.

The potential benefits include producing fermented food, producing new products with desirable characteristics such as disease- and drought-resistant plants, developing life-saving vaccines such as insulin, and producing wide ranges of non-food products and raw materials.

Throughout the centuries, fermentation has been used by many different cultures to preserve and prepare food and medicine. Even now, it still remains one of the most important methods. Biotechnology proposes new methods of achieving adequate and improved food supply. To achieve this goal, two biotechnology methods, namely, genetic selection and genetic engineering, are adopted.




Genetic engineering allows scientists to take the gene that controls the trait of one organism and insert it into another organism that does not have the gene without having to go through the trial and error process of selective breeding. Genetic engineering is, therefore, extremely rapid compared to selective breeding. With genetic engineering, scientists can also cross-breed very easily. There is a variety of techniques used to modify plants and animals through genetic engineering. One way is the insertion of genes to create plants that are resistant or tolerant to insects, weeds, diseases, cold temperatures and droughts.E.g. Scientists have taken a gene from a coldwater fish and introduced it in potatoes to protect the

seedlings against sudden frost.

Genetic engineering can also be used to change the properties of crops, adding nutrients, making them taste better or reducing the growing time.E.g. The production of golden rice is a good example. Many countries in the world rely on rice as

their primary food source. Unfortunately, rice lacks many essential vitamins and minerals. One of the most severe consequence of malnutrition is blindness caused by vitamin A deficiency. With genetic engineering, genes responsible for producing the precursor of vitamin A have been inserted into rice plants which now have higher levels of vitamin A in their grains. This type of rice is known as golden rice.

Genetic engineering is used in animal breeding too. Its obvious use will increase milk, meat and egg production, to improve the resistance to diseases and tolerance of harsh environments. Genetically engineered animals may also be able to produce compounds needed for producing vaccines and antibodies for medical treatments.

When scientists take the gene that carries the desirable characteristic from one organism and introduce it into the genetic material in the cell of another, the organism that receives the gene is known as a genetically modified organism.

There are benefits to producing genetically modified organisms (GMO).




Telecommunications change the way information is transmitted. The development of communications satellite that allows for more effective communication and

interaction between people over great distances.




Other forms of communication technology include the handphone and the Internet.

The handphone gives us the ability to take advantage of doing business on the move. It also gives us added convenience as we are able to communicate with others wherever we are.

The Internet is the world’s largest computer network, it allows the use of emails, Internet phone, the World Wide Web which allows for the convenience of surfing for information in the comfort of the home.

The speed of the Internet and the ability to provide direct communication allows for the fast spreading of news and information.

It is also an entertainment utility that also acts as a commercial tool for online transactions to take place.




P6 Man and Impact on Environment Notes

Documents

encourage algae growth

smart learning centre

kill marine life

marine life

carbon dioxide

acid rain

fossil fuels

large amounts