AP 8th Class Biology 7th Lesson Questions and Answers Pollution of Air and Water

AP State Board new syllabus 8th Class Biology Guide 7th Lesson Reproduction in Animals Textbook Exercise Questions and Answers.

AP 8th Class Biology 7th Lesson Questions and Answers Reproduction in Animals

8th Class Biology 7th Lesson Reproduction in Animals Questions and Answers (Exercise)

Question 1.
What are the different ways in which water gets contaminated ?
Answer:
Sources of water pollution :

• Many factories and industries discharge their harmful chemicals into rivers and streams directly without treatment.
• In organic chemical fertilisers, pesticides and weedicides used in agricultural activities, dissolve in water and are washed away into water bodies from the fields.
• Dumping of untreated domestic sewage.
• Releasing of hot waters directly into streams and rivers.

Question 2.
At an individual level, how can you help reduce air pollution?
Answer:
We can reduce the air pollution by doing the following steps.

• Use public transport in place of private or own vehicles.
• Plant trees or grow vegetation in your surroundings. Nurture the plants already present in your locality.
• Use CNG vehicles, electric vehicles in place of petrol and diesel vehicles.
• Use only unleaded petrol in vehicles.
• Create awareness to the people on the effects of air pollution.

Question 3.
Clear, transparent water is always fit for drinking. Comment.
Answer:

• No. Clear and transparent water is not always fit for drinking.
• Water might appear clean but it may contain some disease causing micro-organisms and other dissolved impurities.
• Hence it is advised to purify water before drinking.
• Purifying can be done by water purifying systems or by boiling the water.

Question 4.
You are a member of the municipal body of your town. Make a list of measures that would help your town to ensure the supply of clean water to all Its residents.
Answer:
I will suggest the following measures to ensure the supply of clean water in our town. They are

• To minimise the wastage of water in supply lines, we should repair the water supply lines without leakages. This can stop the wastage of water during the supply.
• Frequent monitoring on treatment of water purification at storage tanks.
• Taking measures for frequent chlorination of water before supply.
• I should take measures to avoid contact of water supply lines with sewage pipes.
• I should take measures to minimise the water wastage by creating awareness among
  the public on the importance of saving water.

Question 5.
Explain the differences between pure air and polluted air.

Pure air	Polluted air
1) It has no smell (or) odour.	1) It has pungent or foul smell.
2) It is clear and transparent.	2) It is not clear and translucent
3) Visibility is high.	3) Visibility is low due to presence of smoke and dust particles.
4) It is healthy for living organisms.	4) It is harmful for living organisms..

Question 6.
Explain circumstances leading to acid rain. How does acid rain affect us ?
Answer:

• Pollutants like sulphur dioxide, nitrogen dioxide etc…. react with the water vapour present in the atmosphere.
• This results in the formation of sulphuric and nitric acids respectively.
• These acids mix in the rain water and thus make it acidic. This is called acid rain.

Affects of acid rains

• Acid rain increases the corrosion of metals.
• It destroys crops and wild plants.
• It causes damage to steel, rail tracks, monuments and electrical equipment.
• It causes damage to fresh water life.
• Acid rain removes basic nutrients like calcium from the soil.
• It causes irritation to eyes, nose and throat.

Question 7.
Which of the following is not a greenhouse gas ?
a) Carbon dioxide
b) Sulphur dioxide
c) Methane
d) Nitrogen
Answer:
(d) Nitrogen.

Question 8.
Describe the ‘Greenhouse Effect’ in your own words.
Answer:

• Generally, we have seen greenhouse in nurseries. In this the sun’s heat is allowed to get in but it is not allowed to go out:
• The trapped heat warms the greenhouse.
• The trapping of radiations by the earth’s atmosphere is similar, so it is called “Green House Effect”. Now, it threatens life.
• Excess of CO₂ in air is one of the gases responsible for this effect.
• CO₂ Methane (CH₄ Ozone (O₃) and water vapour are also called as greenhouse gases.

Question 9.
Prepare a brief speech on global warming. You have to deliver the speech in your class.
Answer:

• CO₂ traps heat and does not allow it to escape into space.
• As a result, the average temperature of the earth’s atmosphere is gradually increasing. This is called “global warming”.
• Methane, nitrous oxide and water vapour also contribute towards this effect. These are called greenhouse gases.

Affects of global warming :

• It can cause sea levels to rise dramatically. Low lying coastal areas have already been flooded.
• Global warding could result in wide ranging effects on rainfall patterns agriculture, forests, plants and animals.
• Scientists estimated that if the greenhouse gases are released at present level, the temperature may rise by more than 2°C by the end of this century. It may result in the submergence of many coastal cities like Mumbai, New York etc…. in the world.
• Due to increased temperatures, the glaciers in Himalayas and polar regions will melt down. It results in huge floods in rivers like Ganga and rise in sea water levels.

Many countries have reached an agreement to reduce the emission of greenhouse gases. The kyoto protocol is one such agreement.

Steps to reduce the effects of global warming :

• Minimise the usage of fossil fuels like petrol and diesel.
• Encourage the people to use eco – friendly fuel resources like solar energy, wind energy, CNG and LPG.
• Stop deforestation.
• Plant trees where ever possible.

Question 10.
Describe the threat to the beauty of the Taj Mahal.
Answer:

• India’s most famous tourist attraction the Taj Mahal, located in Agra.
• Experts have warned that pollutants in the air are discolouring it’s white marble.
• The industries located in and around Agra like rubber processing, automobiles, chemical factories and Mathura oil refinery, have been responsible for producing pollutants like sulphur dioxide, and nitrogen dioxide.
• These gases react with the water vapour present in the atmosphere to form sulphuric acid and nitric acid. These acids come down as acid rain and corrode the marble of the monument. This phenomenon is also called “Marble Cancer”.
• Soot particles (S.P.M – Suspended Particulate Matter) emitted by Mathura Oil Refinery, has contributed towards the yellowing of marble.
• The Supreme Court has taken several steps to save the Taj. They include.
  a) All industries in and around Agra must switch to cleaner fuels like CNG and LPG.
  b) Moreover, automobiles should switch over to unleaded petrol in the Taj Zone.

Question 11.
Why does the increased level of nutrients in the water affect the survival of aquatic organisms ?
Answer:

• Excessive quantities of chemicals like nitrates and phosphates present in the fertilisers act as nutrients for algae to flourish.
• When these algae die, decomposers such as bacteria use the oxygen present in the. water to decompose the algae.
• This results in the reduction in the oxygen level of the water, which adversely affects the survival of aquatic organisms.

Question 12.
How does CO₂ content rise in the atmosphere and become excessive?
Answer:

• CO₂ is being continuously released because of human activities like deforestation, burning of fossil fuels indiscriminately.
• As a result the average temperature of the earth’s atmosphere is gradually increasing. This is called “global warming”.

Question 13.
Why do we need to filter water before drinking ?
Answer:
Water may contain harmful microbes, silt, dust, foliage etc… which make it unfit to drink. So, it is necessary to filter the water to make it potable.

Question 14.
What will happen if we drink polluted water?
Answer:
If we drink polluted water, then we will fall sick, as it contains harmful microbes that cause many serious diseases like Cholera Typhoid etc….

Extended Learning – Activities And Projects

Question 1.
In some cities, a pollution check has been made compulsory for vehicles. Visit a petrol pump in order to learn about the process of conducting a pollution check. You may systematically record your findings in the following areas:

* Average number of vehicles checked per month.
Answer: 360 approximately.

* Time taken to check each vehicle.
Answer: 5-7 minutes

Pollutants checked for
Answer:
Carbon dioxide, carbon monoxide, nitrogen, nitrogen oxide, methane, hydro carbons, sulphur dioxide, particular matter, trace elements, water vapour etc.

* The process of testing :
Answer:

• The test shall be carried out with the engine mounted on a test bench and connected to a dynamometer.
• The gases emission from the exhaust of the engine include hydrocarbons, carbondioxide, carbon monoxide and oxides of nitrogen.
• During prescribed sequence of warmed up engine operating conditions, the amount of the above gases in the exhaust, shall be examined continuously.
• The prescribed sequence of operations consists of a number of speed and power modes which span the typical operating range of engine.
• During each mode, the concentration of each pollutant, exhaust flow and power out put shall be determined and the measured values, weighed and used to calculate the grams of each pollutant emitted for kilowatt hour.

* Permissible limits of emission of various gases.
Answer:

Petrol engine		Diesel engine
Carbondioxide	14%	Nitrogen	67%
Carbon monoxide	1 to 2%	Carbondioxide	13%
Nitrogen oxide	less than 0.5%	Water vapour	11%
Hydrocarbons	0.5%	Carbon monoxide	less than 0.045%
Sulphur dioxide	possible traces	Nitrogen oxide	less than 0 to 1.5%
Particular matter	less than 0.5%	Sulphur dioxide	less than 0.03%
Trace elements	less than 0.5%	Hydro carbons	less than 0.43%
Nitrogen	71%	Particulate Pollutants	less than 0.045%
Water vapour	12%	Trace elements	– 0.3%

* Measures taken if the emitted gases are above the permissible limits.
Answer:
The carbon particles (soot) deposited in the engine head will be checked and cleaned or the vehicle will be ceased by .R.T.O.

* How frequently is a pollution check required?
Answer:
For every six months.

Question 2.
Conduct a survey in your school to investigate various environment related activities that have been undertaken. The class can divide itself into two groups, with each group looking at a different area. For example, one group can find out whether there is an environment club in the school. What are its objectives? What is its calendar of events? How can you become a member?
If your school does not have such a club, you even think of starting one along with a few of your friends.
Answer:

• In our school, we have a programme called “National Green Corps” of the Ministry of Environment and Forests of Government of India.
• Environmental activities in schools in India is promoted through the National Green Corps (NGC)
• It’s Motto – “Where there is Green, there is Prosperity”.

Objectives of NGC :

• Educate children about their immediate environment by increasing awareness.
• Impart knowledge about ecosystems, their interdependence and need for survival through visits and demonstrations.
• Mobilize youth by instilling a spirit of scientific inquiry into environmental problems.

Activities (or) Events taken up by NGC :

• NGC students participate in activities related to conservation of biodiversity conservation of water and conservation of energy etc…..
• They also take up environmental awareness activities among public on environmental issues.
• They promote environmental discipline among public.
• They also take up activities like plantation activities, construction of soaking pits, compost pits etc…. in schools.

How can one become a member of NGC ?
By filling an application form, any student in our school can become a member of NGC club. He will get a Green Passport also.

Question 3.
Organise a field visit to a river in or around your town with the help of your teachers. Observations followed by discussion could focus on

• the history of the river.
• cultural traditions.
• role of the river in meeting the town’s water needs.
• pollution concerns.
• sources of pollution.
• effects of pollution on the people living by the riverside as well as those living far away.

Answer:
Kolleru lake : It is a 2nd largest fresh water lake located in Andhra Pradesh located between Krishna and Godavari delta.

History : Two copper plates of the early Pallava dynasty have been found in the lake, tracing it’s history to Langula Narasimha Deva an Ganga Vanshi Odisha King. According to legend, the Gajapathi fort was located at Kolleti kota on one of the eastern islands of the lake.

The enemy general “Muhammadan” general escaped at “Chiguru kota” located on the shores. In some ways the lake protected the Oriya forces. The enemy finally tried to excavate a channel, the modern day Upputeru. So that the water of the lake would empty into the sea and the level would fall so that they could attack the Gajapathi fort.

The royal Oriya Army general sacrificed his own daughter to propitiate Gods and ensure his success against Muhammadan and her name was “Perantala Kanama”. Therefore the channel was called Perantala Kanama. “Sri Peddinti Ammavari Temple” is one of the oldest and famous temples found in Kolleru.

Water sources available other than Kolleru: Wells, taps. The lake is fed directly water from seasonal Budameru and Tammileru streams and connected to the Krishna and Godavari systems by channels.

Cultural traditions : The vast majority of the district is rural in nature. Thus the culture of the Kolleru lake people is mostly conservative and traditional. The joint family system, the arranged marriages are the norms. Telugu language is spoken in this place.

Pollution concerns: Kolleru lake is suffering from the unsatisfied greed of people and selfish interests of mankind who exploit the lake’s integrity. Thousands of fish tanks were dug up effectively converting the lake into a mere drain. This had great impact in terms of pollution, leading to difficulty in getting drinking water for the local people.

Source of pollution : Satellite images taken on February 9, 2001 by the Indian remote sensing satellite found that approximately 42% of the 245 km² lake was occupied by aquaculture. While agriculture had encroached another 8.5% they were mostly rice paddies. Surprisingly no clear water could be found in the satellite image. The rest of the lake is being diminished by weeds like elephant grass and water hyacinth.

Effects of pollution on people : Thousands of fish tanks were dug up effectly leading to difficulty in getting drinking water for the local people. An adverse effect on the thousands of acres of crop in the upper reaches of water flow into the sea because of obstruction by bunds of the fish tanks that appeared illegally.

Question 4.
Find out with the help of your teachers and the internet (if possible), whether there are any international agreements to control global warming. Which are the gases covered under these agreements ?
Answer:
Many countries have reached an agreement to reduce the emission of green house gases. Like CO₂ methane, SO₂, etc…. The Kyoto protocol was adopted on 11 December 1997. Presently 197 countries signed on this protocol after many satifications. It is intended to solve the long term international problem.

8th Class Biology 7th Lesson Questions and Answers (Lab Activities)

Activity-1

How do you compare the quality of air in a park and busy road, a residential area and an industrial area, a busy traffic intersection at different times of the day (morning / afternoon / evening) in a village and town ?
Answer:
I will visit the places listed above and observe the quality of air at these places. I will note down my observations in the field book.
Observations:

Name of the place	Early morning	Afternoon	Evening
Park	The air is fresh with­ out any pollutants.	The air is fresh because of green trees.	A little bit of dust is observed.
Busy Road	The air is fresh with­out dust.	Pollution level is higher.	Pollutants are extremely high.
A residential area	The air is pure and fresh.	Pollutants like smoke and dust, are seen.	Dust and fumes are seen.
Industrial area	Only some dust and smoke is seen.	Smoke and flames are high in the air.	Pollutants are gradually increasing.
A busy traffic intersection	Pollution levels are not high	Pollution is high when compared to morning.	Pollution levels are much higher than afternoon.

Villages are not generally polluted when compared to towns.

Activity-2

You might have read in the newspapers that respiratory problems amongst children – are rising day by day. Conduct a survey of households in your neighbourhood and among friends to find out how many children are suffering from respiratory problems.
Answer:
Students have to conduct a survey in their neighbourhood and show the results in a tabular form as follows.

Sl.No	Name of the child	Respiratory problem identified

Activity-3

Prepare a table using the pollutants mentioned. You may even add more data to the following table.

Sl.No	Name of the child	Respiratory problem identified

Answer:

Air Pollutants	Sources  A	Effects
Carbondioxide	Automobiles, factories	Global warming, respiratory diseases.
Sulphur dioxide, Nitrogen oxides, Nickel, Lead Soot Particles	Industries	skin diseases, respiratory diseases like asthma and allergies SO2 causes breathlesness in human beings and animals. It checks the growth of plants.
Carbon monoxide	Incomplete combustion of fossil fuels.	It interferes with oxygen transport in the body.
CFC (Chloro Fluoro Carbons)	Aeroplanes, Jet planes,Refrigerators, Air conditioners, Aerosol spray	Destroys ozone layer It causes diseases related to lungs, eyes, skin and digestive system.

Activity-4

You have various options of commuting to your school such as walking, going by bicycle, travelling by bus or other public transport, using a car individually, travelling by car pool. Discuss in your class the impact of each of these options on the quality of air.
Answer:

• Walking, going by bicycle, travelling by bus, or other public transport are examples for eco – friendly activities.
• By practicing eco – friendly activities in our daily life, we can lower the air pollution levels in our surroundings.
• These activities not only conserve fossil fuels but also improve the quality of the ambient air.
• These activities help us to improve our health and to get a better surroundings.
• These practices boost up the developing economy of our country.

Activity-5

Try to collect samples of water from a tap, pond, river, well and lake.Pour each into separate glass containers. Compare these for smell, acidity and colour. Complete the following.

Water Sample	Smell	Acidity	Colour
Tap Water
Pond Water
River Water
Well Water
Lake Water

Answer:
Observations:

Water Sample	Smell	Acidity	Colour
Tap Water	Smells	Neutral	Dull
Pond Water	Light smell of soil	Yes	Muddy
River Water	Smells a little	No	Colourless
Well Water	Smells	Yes	Dull
Lake Water	Smells	No	Muddy

Note : Water is polluted when substances such as domestic sewage, toxic chemicals, effluents etc get mixed with it.

Activity-6

You had investigated the sewage disposal system of your locality in Class VII. Do you remember how the sewage was collected from your home and where it went there after?
Answer:
The underground network of small and big pipes called sewers carries the sewage ‘from the point of production to the point of disposal i.e treatment plant.

Activity-7

How do you construct a water filter with simple everyday material ?
Answer:
1) Take a plastic bottle and cut it into two halves at the centre.
2) Use the upper half as a funnel by putting it upside down in lower half.
3) Make layers in it with paper napkin or a fine cloth followed by cotton, sand and then gravel.
4) Now pour dirty water through the filter and observe the filtered water.
Observation : The filtered water was free of impurities.

Activity-8

Investigate the level of awareness about water pollution in your area. Collect data on the sources of drinking water and the methods of sewage disposal. What are the common water-borne diseases in the community? You can consult your local doctor/ health worker for this. Which are the governmental and non-governmental organisations working in this field? What are the measures being taken by them for generating awareness ?
Answer:

• Sources of drinking water are rivers, wells, tube wells, lakes, ponds and streams are the sources of drinking water.
• The common water borne diseases in the community are Cholera, Typhoid, Hepatitis, Amoebic dysentery etc…..
• Ministry of Environment and Forests, Government of India and NGOs like Bhumi, Swades Foundation, Watershed Organisation Trust (WOTR) Gramin Vikas Vigyan Samiti, Navjyoti India Foundation are working in the field of conservation of water bodies in India.