Folio Biology

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FOLIO BIOLOGY CHAPTER 9: ENDANGERED ECOSYSTEM BY: NUR SABRINA SHAHIRAH BINTI MOHD SHAHAR 408 10256 HARMONIOUS

Transcript of Folio Biology

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FOLIO BIOLOGY

CHAPTER 9:

ENDANGERED ECOSYSTEM

BY:

NUR SABRINA SHAHIRAH BINTI MOHD SHAHAR

40810256

HARMONIOUS

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9.1

Human Activities That Endangered An

Ecosystem

HUMAN ACTIVITIES THAT HAVE UNDESIRABLE EFFECTS ON THE ENVIRONMENT

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Deforestation

Leads to

1. Soil erosion2. Landslides3. Flash floods4. Climate changes5. The loss of biodiversity6. The green house effect and global warming

Burning of fossil fuels

Leads to

1. The green house effect2. Global warming3. Air pollution

Overuse of fertilisers in intensive farming

Leads to

1. Eutropication2. Water pollution

Dumping of domestic and industrial waste

Leads to

1. Water pollution

POLLUTION

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Pollution can be defined as any undesirable 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.

Air pollution

Pollutants enter the air from various sources, but burning of fossil fuels contributes the most to air pollution.Exhaust fumes from vehicles contain soot (tiny carbon particles), lead (from cars using unleaded petrol), carbon monoxide oxides of nitrogen and hydrocarbons due to the incomplete combustion of fossil fuels.Burning of fossil fuels in the combustion engines of vehicles and electrical power station also releases large amounts of carbon dioxide into the atmosphere.Human activities such as open burning cause severe smog and haze.Industrial plants and factories also pump large amounts of carbon monoxide, oxide of nitrogen and sulphur dioxide into the atmosphere.Both oxides of nitrogen and sulphur dioxide can combine with water vapour in the atmosphere to form nitric acid and sulphuric acid respectively.Then, they fall back to the Earth as acid rain.Rainwater typically has a pH value of 5.6, due to the presence of dissolved carbon dioxide, which forms carbonic acid.The pH of acid rain is, however, less than 5.0.

Water pollution

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Human activities are the main reason why water pollution in most countries has reached a critical point.Waste matter from industrial and domestic sources that is dissolve or suspended in water contributes to the deterioration of water quality.We have discussed how run-offs of fertilisers into lakes and river affect the freshwater ecosystems through eutrophication.Eutrophication occurs when inorganic nutrients and organic material enter a river or a lake.The discharge of untreated sewage into a river also has an immediate effect on the biotic and abiotic components of the water ecosystem.The enrichment of lakes and rivers with nutrients encourages photosynthesising organisms in the water, particularly algae, to grow rapidly, resulting in a population explosion known as algal bloom.The density of the algae may be so high that light intensity in the water is greatly reduced.The death of plants and algae and the subsequent decomposition of these organisms by bacteria lead to a severe depletion of oxygen in the water, causing the death of aerobic organisms.The rapid growth of microorganisms in water leads to the increase in biochemical oxygen demand (BOD).BOD refers to the amount of dissolved oxygen taken up by microorganisms that decompose organic waste matter in water.The dissolved oxygen concentration can be used as an indicator of water pollution level.A high BOD value indicates the presence of a large number of microorganisms and this suggests a high level of pollution.Industrial waste can include heavy metals such as lead and mercury and radioactive waste which also find their way into rivers or lakes.Illegal dumping of waste matter and effluent from heavy industries is the main source of heavy metal pollution.Lead can also leak out through lead pipes which are used in plumbing.Many of these heavy metals are highly toxic, last for a long time and can accumulate in living organisms via the food chain.Radioactive waste can cause cancer and leukaemia.

Thermal pollution

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Water temperature can affect the level of dissolved oxygen.When water temperature increases, oxygen becomes less soluble.Water is used as a cooling agent in many industrial processes and cooling towers of electrical power station.The hot water produced is discharge directly into nearby lakes or rivers, leading to thermal pollution.Thermal pollution occurs when excess heat, which is released into the environment, harms living organisms and the environment.The increase of water temperature has an impact on the survival of fishes and other aquatic organisms which can only survive within a certain range of temperatures.For some species, a sudden increase in temperature can cause instant death.This has a negative effect on the food chain and may disrupt the entire ecosystem.For organisms like the algae, an increase in temperature encourages rapid growth which leads to a higher BOD value.

Noise pollution

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Noise from cars, motorcycles, aeroplanes, construction sites, agricultural and industrial machinery can be a form of pollution.The noise level of residential areas should not exceed 55 decibels (dB).According to the World Health Organisation (WHO), prolonged exposure to noise levels at or above 80 dB can cause deafness.Excessive exposure to noise is considered a health risk because noise can contribute to the development and aggravation of stress related problems such as high blood pressure, coronary disease, ulcers, depression and headaches.

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STRATEGIES TO SOLVE PROBLEMS RELATED TO POLLUTION

We have seen the effects of pollution on living things and the environment. We cannot continue to pollute the environment, thinking that we will not suffer any of the consequences. All efforts must be made to control and stop pollution. One way to curb pollution is by formulating short-term and long-term strategies to reduce or

stop pollution before it happens.

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9.2

The Greenhouse Effect And The Thinning Of

The Ozone Layer

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The greenhouse effect

When sunlight enters the Earth’s atmosphere, some of its solar radiation is reflected back into space.As the Earth is warmed, heat in the form of infrared radiation is radiated back into space.However, much of this heat does not escape from the atmosphere, but remains trapped by the greenhouse gases.At the same time, greenhouse gases also radiate heat in the form of infrared radiation back to the Earth.In this respect, greenhouse gases behave a lot like the glass panels of a greenhouse which trap heat and warm the greenhouse, hence the term greenhouse effect.The greenhouse effect is an important natural process.Without it, the Earth would be too cold for the survival of living organisms.Carbon dioxide, from coal-fired power stations and vehicle exhausts, is the main greenhouse gas.Other contributary pollutants include chlorofluorocarbons (CFC)s, methane, nitrous oxide and ozone.Today, data collected around the world show a steady increase in the concentration of greenhouse gases.Since the beginning of the Industrial Revolution, the atmospheric concentration of carbon dioxide has increase by nearly 30% while the concentration of methane has more than doubled.Scientists believe that the burning of fossil fuels and other human activities such as deforestation and industrial production are the primary reasons for the increased concentration of atmospheric carbon dioxide.As the concentration of greenhouse gases rises, the greenhouse effect becomes more pronounced.As more heat is trapped in the atmosphere, the Earth’s average temperature rises.This is known as global warming.Over the last 40 years, the Earth’s average temperature has increased by about 0.20C-0.30C.In Malaysia, the temperature is rising at 0.180C every decade.In the absence of emission control policies, carbon dioxide concentrations are projected to be 30-150% higher than today’s levels and the Earth’s average temperature may rise between 1.50C to 4.50C by 2100.We have examined how the change in the Earth’s atmospheric composition increases the ability of the atmosphere to trap heat.

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The thinning of the ozone layer

The ozone layer is a region in the atmosphere, situated between 17 and 25 kilometres above the Earth’s surface.The thinning of the ozone layer has been recorded by scientists since the 1970s.In 1985, it was reported that the stratospheric ozone concentrations over the Antarctica had declined by 40% since 1977.The atmosphere in this area has very low ozone concentrations, resulting in the formation of an ozone hole.An ozone hole has now appeared above the Artic as well.Consequently, ultraviolet radiation has since risen by 7% in a decade in the northern hemisphere and in the southern hemisphere, the increase is 10%.The destruction of the ozone layer is mainly due to the increasing levels of chlorofluorocarbons (CFC) in the atmosphere.CFCs are a group of chemical compounds that contain chlorine, carbon and fluorine.These gases are used as coolants in air conditioners and refrigerators, as propellants in aerosol cans and as foaming agents in the making of styrofoam packaging.Since these chemicals are stable, they can persist in the environment for as long as 75 to 100 years.

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Impact of the global warming and the thinning of the ozone layer on the ecosystem

Global warming and the thinning of the ozone layer both have an enormous impact on the ecosystem.The average increase in the Earth’s temperature could change weather patterns and agricultural output.There is also convincing evidence from research carried out by scientists that links the melting of the polar ice caps to global warming.This is turn leads to a corresponding rise in sea levels.By absorbing most of the ultraviolet radiation, the ozone layer shields living organisms on Earth from damaging effects of ultraviolet radiation.The consequences of the thinning of the ozone layer can be quite severe.The incidence of skin cancer and cataracts among the population will be on the increase.

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9.3

The Importance Of Proper Management

Of Development Activities And The

Ecosystem

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The need for development and the effects of an increased population on the ecosystem

We have examined closely how human activities can cause so much destruction to the environment.However, this does not mean humans always have to influence the environment in a negative way.We can also bring about positive effects on the environment by taking measures to carry out proper management of development activities such as conserving and preserving living organisms and the environment. As the country’s population continues to increase, so do the people’s needs.The Earth’s natural resources are relentlessly exploited to fulfil these needs.Recall from unit 9.1 how the rainforests disappear to make way for development.For example, to provide electrical power to the whole country, dams are constructed across rivers with little consideration of their impact on the environment.In the process, human interfere with the balance of nature through their activities and contaminate the environment with pollutants.Conflicts therefore arise, between the need to meet the requirements of an increasing population and the need to deal with growing environmental problems.

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Managing development activities to ensure a balanced ecosystem

It is obvious that we cannot continue to pollute the Earth without facing the consequences.Our demands for resources have to be balanced with the need to sustain the resources themselves.The key to solving this issue is sustainable development.A country is developing if there is continuous development and improvement in the lives of the people.This would include health, education and other living conditions.To be sustainable, the development activities must go on without jeopardising or damaging the resources of the country.Development activities must take into consideration the environmental impact.It is imperative that we should not look only for short-term gains while ignoring the long-term effects on the environment.Sustainable development depends largely on the rate at which we use the renewable resources.The goal is to exploit natural resources in a sustainable manner so that given time, these resources can replenish themselves and be available for future generations without experiencing a decline.For example, forests must be managed properly so that they can continue to perform their vital environmental functions and to realise their enormous economic potential.One way to exploit our forests in a sustainable manner is to make sure we establish a level of selective harvesting, so that we do not take more than can be replenished.The number of mature trees which can be removed must be replaced by replanting new trees.Greater productivity from existing agricultural lands will also reduce the pressure to convert more forests to these uses.In this way, we can still continue to farm and harvest timber while protecting the Earth’s biodiversity.

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List

Of

References

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List of references

Text book

Biology references book (SUCCESS)

Internet

Teachers

Friends

Parents

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Appendix

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Human activity that endangered an ecosystem

Air pollution

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Water pollution

Thermal pollution

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Noise pollution

The greenhouse effect

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The thinning ozone layer

The importance of proper management of development activities and the ecosystem

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The

End