Speaker Domes
Diamonds are believed to actually enhance the performance of high quality speakers. Because
diamonds are a very stiff material, they can vibrate rapidly when made into a thin dome without
the deformation that can degrade sound quality.
Windows
Diamond windows are made from very thin diamond membranes. These thin diamond membranes
are used to cover openings in things like lasers, vacuum chambers, and x-ray machines. Diamond
membranes are durable, resistant to heat, and transparent, making them highly useful.
Abrasives
Because diamonds are so hard and durable, they are ideal for grinding, cutting, drilling, and
polishing. When used as an abrasive, very small pieces of diamond are embedded into grinding
wheels, saw blades, or drill bits.
Heat Sinks
A heat sink is a passive component in an electronic system that cools a device by dissipating heat
into the surrounding air. Diamonds have very high thermal conductivity, which means they are
excellent heat conductors. Because of this, diamonds are used as a material for heat sinks.
Engraving
Diamond is used for the engraving of stones made of granite, quartz, and other very hard
materials. Because diamonds will not break or even scratch against the surfaces of other tough
stones, using them for engraving is quite practical as the work can be completed without having
to worry about replacing the engraving bit.
Potential Future Uses
In the future, diamonds may be used for surgical tools, medical devices, and prosthetic human
joints. Research is being conducted into whether or not the Earth’s hardest naturally occurring
substance could be of any use to the medical community. ?DO
Graphite: Graphite is a dark grey and soft The lead pencil is made up You
allotropes of carbon. It possesses a metallic luster of graphite. But we called Know
and has a soapy touch. It is more widely distributed it lead why? It is because
in nature than a diamond. Pure graphite is graphite is soft and can’t
manufactured by heating coke to a temperature of be used to write, to make it
about 3000oC in an electric furnace. It is non- strong, small amount of lead
soluble in ordinary solvents and is not attacked by is added in it so we called
acids and alkalis. pencil’s graphite as “lead”
In graphite crystal, one carbon atom is bonded by three other carbon atoms
by covalent bonds. Thus only three electrons are used in the formation of
bonds and the fourth electron is free to move. Due to these reason, the free
electrons in graphite conduct heat and electricity, and thus graphite is a
good conductor of heat and electricity.
Blooming Science Book 9 201
The important uses of graphite are as follows
1. The major use of graphite is in making lead pencils of different hardness, by mixing it
with different proportions of clay. The weakly held layers of carbon atoms in graphite
easily slide over each other and are left behind on paper as black marks.
2. Due to its slippery nature, graphite is used as a dry lubricant in machine parts.
3. Being resistant to chemicals and having a high melting point and also because
it is a good conductor of heat, graphite is used to make crucibles.
4. The presence of free electrons makes graphite a good conductor of electricity
and it is used to make electrodes.
5. Graphite has the ability to absorb fast-moving neutrons, thus, it is used in
nuclear reactors to control the speed of the nuclear fission reaction.
Property Diamond Graphite
Appearance Graphite is a black, opaque and
Diamond is a transparent shiny substance.
Hardness substance having extraordinary
brilliance. Graphite is soft, having a soapy
touch.
Diamond is extremely hard. Graphite is lighter than a
diamond. Its density is 2250 kg/
Density Diamond is quite heavy. Its m3.
density is 3510kg/m3. Graphite is moderate conductor
of heat.
Thermal conductivity Diamond is a poor conductor of Graphite is a good conductor of
Electrical conductivity heat. electricity.
Diamond is a poor conductor of
electricity.
Amorphous Carbons
Amorphous carbon are non-crystalline carbons. Wood charcoal, sugar charcoal, animal charcoal,
lamp black soot, coke etc are various forms of amorphous carbons. These carbon are insoluble
in ordinary solvents. They are black, porous, brittle and amorphous solid. They are heavier than
water but float on it due to large quantities of air absorbed on its surface. The absorbed air
escapes on heating the charcoal. This is why, a burning piece of charcoal when thrown in water,
it sinks. They are usually non-conductor of electricity and bad conductor of heat.
Charcoal: It is the amorphous form of carbon. Wood charcoal is made by the destructive
distillation of wood. Valuable byproducts includes acetic acid, methyl alcohol (wood alcohol)
and acetone. Wood charcoal is highly porous and has a vast internal surface area.
Wood charcoal is made by burning wood in a limited supply of air in a charcoal pit of kiln. The
charcoal thus obtained, is Pit charcoal. Where the wood is dear, charcoal is obtained by heating
wood in a closed vessels so that air is excluded. The charcoal, thus obtained, is called retort
charcoal.
Lamp Black: It is a soft black powder obtained by burning turpentine oil or other vegetable oils
in an insufficient supply of air.
202 Blooming Science Book 9
Lampblack is used extensively in manufacture of printing inks, black paints, Indian ink and boot
polishes.
Coal: Coal occurs in nature. It is formed in nature as a result of a slow decomposition of
vegetable (organic) matter under the influence of heat and pressure in a limited supply of air. It
is actually so proved by the microscopic examinations of some varieties of coal and the presence
of fossils of trees and plants in the layer of coal.
The first stage in this transformation of vegetable matter into coal is peat, which is found to
contain a lot of organic matter. The carbon content in peat is about 60%. The next stage is the
formation of lignite. It is harder and contains 67% carbon.
Bituminous coal contains about 80% carbon and is the common variety of coal in the market. The
final stage is the formation of anthracite, which contains up to 90% carbon, and is hard, brittle
and produces a high ignition temperature.
Coke: When coal is subjected to destructive distillation it loses all the volatile matter and
the residue left in the retorts is called coke. It is also very pure form of carbon and it is used
extensively as fuel because it burns without smoke. It is also used as a reducing agent and in
making fuel gases. It is a good conductor of electricity and is employed in the lining of furnace
and in making electrodes.
Physical properties of carbon
1. Carbonisavailableinsolidform.Itexistincrystallineform(egdiamondandgraphite)andin
amorphous form (eg coal, charcoal).
2. It doesn’t dissolve in water.
3. It can vaporise directly into from solid when heated strongly.
4. It is black in colour except diamond.
5. Carbon is bad conductor of heat and electricity except graphite.
Chemical Properties of Carbon
1. Combustion
All forms of carbon react with oxygen of air to form their oxides. In a free supply of air or
oxygen, carbon burns to form carbon dioxide.
Charcoal/Graphite/Diamond + oxygen → Carbon dioxide + Heat
C(s) + O2(g) → CO2(g) + Heat
But, in a limited supply of air or oxygen, carbon burns to form carbon monoxide.
C(s) + O2(g) → 2CO(g)
Blooming Science Book 9 203
2. Reaction with Steam
When carbon is heated vigorously with water vapour (steam), carbon monoxide and hydrogen
gases are formed, in this reaction carbon reduces water to hydrogen.
C(s) + H2O(g) ∆ CO(g) + H2(g)
water gas
The mixture of carbon dioxide and hydrogen gas is called water gas. This gas when burns
produces sufficient heat which is used as a source of heat in different industries.
3. Reaction with Metals
Carbon reacts with different metals to form their carbides.
Ca(s) + C(s) → CaC2(s) (Calcium carbide)
Mg + C → MgC2 (Magnesium carbide)
4. Reducing Nature
Carbon is a strong reducing agent. At high temperature, it reduces less reactive metal oxides like
lead oxide, zinc oxide, ferric oxide and copper oxide to their corresponding metals.
PbO(s) + C(s) ∆ Pb(s) + CO(g)
ZnO(s) + C(s) ∆ Zn(s) + CO(g)
Fe2O3(s) + 3C ∆ 2Fe(s) + 3CO(g)
CuO(s) + C(s) ∆ Cu(s) + CO(g)
5. Reaction with Metal Oxide
Carbon when reacts with lime forms calcium carbide and carbon monoxide gas.
3C + CaO (s) → CaC2 (s) + CO (g)
Organic and Inorganic Compounds
Organic Compounds
Organic compounds are the compounds of carbon with the few exceptions like oxides of carbon (CO
and CO2 ), carbonates, bicarbonates, cyanides of metals and carbides. Some examples of organic
compounds are methane, ethane, propane, wax, kerosene, sugar, starch, protein, acetic acid, alcohol,
ether, glycerol, benzene, fatty acids, etc. The organic compounds are covalent compounds. Carbon
has its unique property to join with other carbon atom covalently to form a large carbon chain which
is called catenation property.
Inorganic Compounds
The compounds formed from the elements other than carbon are inorganic compounds. However,
inorganic compounds like oxides of carbon (CO and CO2), carbonates and bicarbonates, cyanides
and carbides are also regarded as inorganic compounds. The inorganic compounds are usually
electrovalent and sometimes covalent as well.
204 Blooming Science Book 9
There are marked differences between the composition, structure and behavior of organic and inorganic
compounds which make their study as a separated branch of chemistry more meaningful. Organic
chemistry deals with carbon and its compounds. Inorganic chemistry deals with elements other
than carbon and their compounds.
Some important differences between organic and inorganic compounds are given in table below.
Differences between Organic and Inorganic Compounds
S.N. Organic Compounds S.N. Inorganic Compounds
These compounds are usually insoluble These compounds are usually soluble
1. in water. 1. in water. Sodium chloride, magnesium
sulphate etc dissolve in water.
2. These compounds are usually volatile. 2. These compounds are usually non-
volatile.
3. These compounds have usually low 3. These compounds have usually high
melting and boiling points. melting and boiling points.
4. These compounds exist as covalent 4. Most of these compounds are ionic, so
molecules, so they are non-electrolytes. they are electrolytes.
These compounds are soluble in organic These compounds are insoluble in
5. solvents like ether, benzene, alcohol, 5. organic solvents.
chloroform, etc. Kerosene dissolves in ether.
Reactions of these compounds are slow. Reactions of these compounds are fast.
6. Examples: Methane, ethane, etc. 6. Examples: Sodium chloride, ammonia,
etc.
Let’s Learn
1. Methane is an organic compound because it contains carbon and the compounds of carbon are
called organic compound.
2. Graphite is good conductor of electricity but not diamond because in graphite, a carbon forms
covalent bonds with only three carbon atoms and there is one free electron in each carbon atom
but diamond does not have.
3. Carbon forms covalent compound because it is a non-metal and non-metals form covalent
compounds by the sharing of electrons.
4. Carbon is a reducing agent because it separates metals from their concerning metallic oxide
when it is heated with the metallic oxides.
C + CuO → Cu + CO
C + PbO → Pb + CO
5. Organic compounds are non-electrolyte because they are covalent compounds and do not
dissociate into ions in molten state and aqueous.
6. Na2CO3, CaCO3 etc. like compounds are not organic compounds even though they have
carbon in them. It is because they are electrovalent compounds and only covalent compounds
having carbon are considered organic compounds [CO2 and CO are covalent and have carbon
but traditionally they are considered as inorganic).
Blooming Science Book 9 205
7. Diamond is hardest substance known because each carbon atom in diamond is joined to four
other carbon atoms giving rise a three dimensional rigid and stable structure.
8. Graphite is used as lubricant because it is soft and non-volatile.
Main Points to Remember
1. Carbon is found in all plants and animals. Carbon exists in different physical forms. Diamond
and graphite are the crystalline allotropes of carbon.
2. A carbon atom has four electrons in its outermost shell. Carbon combines with atoms of other
elements by sharing these electrons and forms covalent compounds. These carbon containing
compounds are called organic compounds.
3. Inorganic compounds are usually electrovalent compounds. Organic compounds are covalent
compounds at all.
4. Organic compounds are insoluble in water, melt or boil at low temperature, burn on heating and
do not undergo electrolysis.
5. Hydrocarbons are the compounds formed by the combination of hydrogen and carbon.
6. Diamond is the purest form of carbon. Graphite is soft allotropes which conduct heat and electricity.
7. Carbon burns with air to form carbon dioxide and in limited air it forms carbon monoxide.
PRO J ECTWORK
Heat some sugar in a spoon to get sugar charcoal and observe various changes occur while
heating.
Exercise
A. Choose the correct answer from the given alternatives:
1. Which of following is not a allotrophe of carbon?
i. diamond ii. coke iii. lead iv. all of above
2. Which chemical property of carbon is the following reaction related to :
PbO +C Pb+CO
i. Reducing nature ii. Combustion
iii. Reaction with metal iv. none of above
3. Which of following is not the properties of organic compounds.
i. They are covalent ii. They have low melting and boiling points
iii. They are soluble in water iv. They have complex composition.
206 Blooming Science Book 9
4. The specific gravity of diamond is :
i. 2.5 ii. 5.3 iii. 0.8 iv. 3.5
5. Which element is present in all organic compounds?
i. Phosphorus ii. Potassium
iii. Nitrogen iv. Carbon
B. Answer the following questions.
1. What is carbon? Write its nature.
2. Prove with an experiment that sugar and candle contain carbon.
3. What is water gas? Write it use.
4. What is caramel?
5. What is catenation? Write some physical properties of carbon.
6. What are organic compounds? Give at least two properties of them.
7. Write any four properties of organic compounds that distinguish them from inorganic
compounds.
8. What is allotropy? Name two allotropes of carbon. Write the uses of diamond and
graphite.
9. What metallic property is shown by the graphite?
10. List two differences between diamond and graphite.
11. Name the following
a) two organic compounds.
b) two carbon containing artificial substances.
c) two carbon containing natural substances.
d) the gas formed when carbon and water is strongly heated.
12. What happens when? Write with balanced chemical equation.
b) Steam is passed over hot charcoal.
b) Carbon reacts with lime.
c) Lead oxide is heated with carbon.
d) Carbon is heated in sufficient oxygen.
13. Give reason:
a) Diamond is a bad conductor while graphite is a good conductor of electricity.
b) Graphite is used as lubricants.
c) Carbon compounds are abundant in nature.
Blooming Science Book 9 207
Chapter WATER
14
Learning Outcomes Estimated Periods: 4+2
On the completion of this unit, the students will be able to:
• describe sources, properties and uses of water.
• describe process of removal of harness of water with chemical equations.
Natural Water
Rainwater is considered one of the purest form of naturally occurring water. Rain is produced
by the condensation of the water vapour present in the air. As rainfall takes place or after snow
melts on high peaks in the Himalayas, the water flows along the surface of the earth and brings
different kinds of impurities. Some of the mineral and organic matters like clay, sand, straw,
bacteria, etc., remain suspended in it and make it muddy and unsafe to drink. Besides gases, the
nature of the dissolved matter depends upon the type of the beds over which river water passes.
Nearly one-third of the rainwater seeps into the ground through soft and loose strata of sand,
gravel and chalk. Soon it reaches some impermeable stratum of clay and slate. It remains in the
form of the water table. In some cases it remains trapped in this layer and tries to escape out from
the small cracks of rocks which we call spring. The water in the well is one example of trapped
water below the ground. Water from wells has been used from time immemorial for drinking and
irrigation purposes. Rivers flow into the seas. The water becomes impure due to the accumulation
of varieties of impurities that have been dissolved.
Source of water
The source from where we can get water for various purposes are called sources of water. Water
is used in agriculture, industries, recreational activities(eg rafting), cleaning environment, daily
human activities (like drinking, bathing) etc. The main sources of water are given in chart.
Sources of water in earth
Seas and oceans Other sources
(97%) (3%)
Glacier, Underground Surface water Other
snow water river water shed
Pond, lake
208 Blooming Science Book 9
On the basis of availability of water, water sources are of main two types:
1. Surface water
The water available on the surface of earth is called as surface water. It exists in the form of
seas/oceans rivers, glaciers, lake, ponds, etc.
a) Seas/oceans
97% of source of water is sea/ocean. This water is salty in taste so we can’t use it directly for
drinking, cooking,etc. But during high tides, this water can be collected to generate electricity.
Sea/oceans are the main source of rain water.
Sea ocean
b) River, strems, Pond and lakes
These are the important sources of fresh water. Our daily activities is performed by the help of
water from these sources. This water is used for agriculture , in industries, for hydroelectricity
and so on.
river pond stream
2. Underground water
During raining, water is absorbed by earth and is collected in rock bed. Such source of water is
called underground water. A body of porous rocks, gravels, sand, silt, sand stone, etc which is
saturated with water in and around it, is called an aquifer. Water in aquifers doesnot remain still
but slowly it is brough to the surface naturally throught spring and waterfalls or it can be released
into lakes, ponds and streams.
Properties of water
1. Physical properties
a) Water is only substance in the earth which exist in all three states of matter ie solid,
liquid and gas.
b) Pure water is tasteless, colourless and odourless.
c) Water can dissolve many of the substances so it is called as universal solvent.
Blooming Science Book 9 209
d) Pure water freezes at 0 oC and boils at 100oC at sea level.
e) Pure water is bad conductor of electricity. And it is nautral to indicator.
f) it is neutral to indicator.
f) Water molecules are attracted each other by a force called as cohesive force.
Water molecules are attracted towards the wall of containers, such a force is
called as adhesive force or adhesive property of water. Due to this property of
water it can wet the glass, clothes, paper, etc. Water is conducted from root of plants
to leaves and branches due to cohesive and adhesive property of water.
g) Surface tension is another property of water. The property of water due to which
its surface resists the external force is called surface tension. Due to surface
tension, small objects having more density such as paper clips float on the
surface of water. An insect named “water strider” can walk on water due to surface
tension.
h) Water has a capacity to rise itself into a very fine capillary tube without the aid of
external force. This property of water is called as capillary action of liquid. The
kerosen rises up in thread without the aid of any external force in the spirit lamp due
to some reason.
Activity
Take a glass of water and insert a narrow tube inside water as in the diagram. What will you
see ? You will see that water in tube rises more in height than the Capillary
tube
surface of water in glass. It is due to capillary action of water. Capillary
2. Chemical properties attracion
a) Some metal like alkali metals and alkaline earth metals
dissolve in water releashydrogen gas.
2Li+H2O LiOH +H2
2Na+ H2O 2NaOH+H2
Ca+H2O Ca(OH)2+H2
b) Acids, base and solubale salt dissolve in water producing ions.
HCl H++Cl-
KOH K++OH-
Solvent property of water
Water can dissolve salts like NaCl (Sodium chloride), KNO3 (Potassium nitrate), etc. But some
salts like AgCl, BaSO4 are in soluble in water. some covalent compound like HCl, alcohol, urea,
etc are soluble in water. Water can dissolve many salts, bases, acids, some covalent compound,
etc so, we called it as universal solvant. The solvant property of water is due to presence of polar-
ty in water molecule. The hydrogen atom in water molecule, slighty attains the positive charges
while the oxygen atom receives parties negative charge. This make the water polar in nature.
210 Blooming Science Book 9
Use of water:
1. It is used for drinking, cooking, bathing,etc.
2. It is used to run factories.
3. It is used for fishery.
4. It is used for jet cutting(process of cutting wood, rubber, etc by passing water at high
pressure)
5. It is used for refreshment like rafting, boating, swimming etc.
6. It is used for generating hydroelectricity.
7. It is used in irrigation.
Hard and Soft Water Scan for practical experiment
Water is the best solvent and it is also known as universal solvent. visit: csp.codes/c09e14
Because of its capacity to dissolve, many substances are mixed with
it. Some of the dissolved substances are useful for plants and animals
whereas some are very harmful. In most of the cases, the salts of
various metals are mixed in water. These soluble salts of metals cause
hardness in water. Soft water is the one which can produce lather with
soap easily. But hard water cannot produce lather as easily as soft
water. These impurities form a thick coat inside boilers.
Hardness of water is due to the presence of soluble salts of magnesium and calcium. The salts
of magnesium such as magnesium bicarbonate, magnesium chloride, magnesium sulphate or the
salts of calcium such as calcium bicarbonate, calcium chloride, calcium sulphate dissolved in
water bring hardness in water.
Hardness of water may be temporary or permanent. Temporary hardness is due to the presence
of salts such as calcium bicarbonate [Ca(HCO3)2] or magnesium bicarbonate [Mg(HCO3)2].
Temporary hardness can be removed easily by boiling.
Permanent hardness is due to the presence of salts such as magnesium chloride (MgCl2),
magnesium sulphate (MgSO4), calcium chloride (CaCl2) and calcium sulphate (CaSO4) dissolved
in water. Permanent hardness can not be removed easily by boiling.
Removal of Temporary Hardness Dead sea has no living ?DO
creature. It contains about
This hardness present in water can be removed by You
using the following methods. Know
1. By Boiling: Salts like calcium bicarbonate 270gm of salt in 1liter of
and magnesium bicarbonate dissolved in water water. It make the water
cause temporary hardness. While heating, higher density giving huge
soluble salts of calcium and magnesium uptrust so nobody sink in
(bicarbonates) change into insoluble salts. The dead sea.
chemical equations are given below.
Calcium Bicarbonate Heat Calcium carbonate + Carbon dioxide + Water
Ca(HCO3)2 CaCO3 + CO2 + H2O
Magnesium Bicarbonate ∆ Magnesium Carbonate + Carbon dioxide + Water
Mg(HCO3)2 MgCO3 + CO2 + H2O
Blooming Science Book 9 211
2. Treating with Lime Water(Clark’s method): Temporary hardness of water can be
removed by treating it with lime water. The chemical equations are given below.
Calcium Bicarbonate + Calcium Hydroxide → Calcium Carbonate + Water
Ca(HCO3)2 + Ca(OH)2 → 2CaCO3 + 2H2O
Magnesium Bicarbonate + Calcium Hydroxide → Calcium Carbonate + Magnesium Carbonate + Water
Mg (HCO3)2 + Ca(OH)2 → CaCO3 + MgCO3 + 2H2O
Removal of Permanent Hardness
Permanent hardness of water cannot be removed by heating only. We know that permanent
hardness is caused by the presence of chlorides and sulphates of calcium and magnesium. Soluble
salts of calcium and magnesium are in turned to insoluble salts by the following methods.
1. Treatment with Washing Soda
Soluble salts of calcium and magnesium change into insoluble salts due to the treatment
with sodium carbonate (washing soda).
Calcium Chloride + Sodium Carbonate → Calcium Carbonate + Sodium Chloride
CaCl2 + Na2CO3 → CaCO3 + 2NaCl
Calcium Sulphate + Sodium Carbonate→ Calcium carbonate + Sodium Sulphate
CaSO4 + Na2CO3 → CaCO3 + Na2SO4
Magnesium Chloride + S odium Carbonate → Magnesium Carbonate + Sodium Chloride
MgCl2 + Na2CO3 → MgCO3 + 2NaCl
Magnesium Sulphate + Sodium Carbonate→ M agnesium Carbonate + Sodium Chloride
MgSO4 + Na2CO3 → MgCO3 + 2Na2SO4
2. Permutit Process
Permutit is the trade name for an artificially prepared sodium Sodium
Hard water chloride
zeolite or sodium aluminium orthosilicate obtained by fusing solution
together sodium carbonate, silica and alumina. Its composition Soft water
resembles Na2Al2SiO8 or Na2Z, where, Z stands for Zeolite = Permutit
Al2SiO8. It possesses higher quantity of reactive Zeolite calcium
and magnesium ions forming insoluble calcium or magnesium Coarse sand
zeolites. Waste
Calcium salts + S odium zeolite→ Calcium zeolite + s odium salts Permutit Process
Ca++ + Na2Z → CaZ + 2Na+
Magnesium salts + sodium zeolite→ magnesium zeolite + sodium salts
Mg++ + Na2Z → M gZ + 2Na+
Thus, by passing hard water through a cylinder packed with permutit, all the ions of soluble salts
of calcium and magnesium responsible for the hardness of water are retained and replaced by
sodium ions. In due course, however, the permutit is exhausted or loses its capacity of reacting
with these salts by having given up all its sodium ions. This can be regenerated by soaking in a
10% solution of common salt when the reverse change takes place and calcium and magnesium
ions pass into solution and sodium zeolite is formed again.
212 Blooming Science Book 9
CaZ + 2NaCl → Na2Z+ CaCl2
MgZ +2 NaCl → Na2Z + MgCl2
The resulting calcium and magnesium chlorides are washed out and the regenerated permutit is
used over again.
Advantages and Disadvantages of Hard Water
Advantages
1. Hard water contains calcium salt dissolved in it which helps to strengthen the bones and teeth.
2. Water is somewhat tasty due to dissolved salts of calcium and magnesium.
3. Hard water is used in beer industries.
Disadvantages
1. Hard water leads to consumption of more soap while washing clothes.
2. A bright white cloth becomes dull due to the salts dissolved in water.
3. In industries, due to hard water, the life of boilers decrease. This is due to the calcium salt
deposited during boiling.
Drinking Water
Water is used for many purposes. The water that contains micro-organism should not be used for
drinking. The water containing micro-organisms is known as contaminated water. Contaminated
water carries many diseases such as cholera, typhoid, and many more. Many other diseases are
transmitted through water. To keep healthy, we must drink safe and clean water. The drinking
water must be boiled. During boiling, the micro-organisms are killed. It is advised that everyone
should drink boiled water to stay away from diseases that transmit through water.
Main Points to Remember
1. The natural sources of water are: rain, river, lakes, springs, wells and sea.
2. Rainwater is the purest form of naturally occurring water.
3. Soft water gives lather with soap easily. Hard water consumes large amount of soap to
give lather.
4. Hardness of water is due to the presence of soluble salts of magnesium and calcium, e.g.
calcium sulphate, calcium bicarbonate, magnesium bicarbonate, magnesium sulphate, etc.
5. There are two kinds of hardness present in water.
a) Permanent hardness and b) Temporary hardness
6. Temporary hardness of water is due to the presence of soluble salts of magnesium and
calcium such as Calcium bicarbonate and Magnesium bicarbonate.
7. Permanent hardness of water is due to the presence of soluble salts of magnesium and
calcium such as magnesium sulphate, magnesium chloride, calcium sulphate, calcium
chloride.
8. Water cycle is a process in which the see water changes into vapour, vapour changes into
snow in high altitude and snow melts into water drops which comes to the earth in the
form of rain.
Blooming Science Book 9 213
9. Temporary hardness of water can be removed by:
a) Heating hard water
b) By treating it with lime water
10. Permanent hardness of water can be removed by:
a) Treating with washing soda
b) By using permutit process.
11. Advantages of hard water are:
a) Hard water contains calcium salt dissolved in it which helps to strengthen the bones
and teeth.
b) Water is somewhat tasty due to dissolved salts of calcium and magnesium.
c) Hard water is used in beer industries.
12. Disadvantages of hard water are:
a) Hard water leads to consumption of more soap while washing clothes.
b) Bright white clothe becomes dull due to the salts dissolved in water.
c) In industries, due to hard water, the life of boilers decrease. This is due to the
calcium salt deposited during boiling.
13. Water is called universal solvant.
14. The adhesive and cohesive properties of water help plants to conduct water
and mineral from roots to different parts.
15. The surface tension of water is due to attraction of molecules of water below the
surface of water.
PRO J ECTWORK
Collect various samples of water like rain water, tap water, underground water, etc from the
resources nearby you. Test the nature of collected water by washing clothes with soap and find
whether the water is hard or soft? Discuss about your conclusion in your class.
Exercise
1. Choose the correct answer from the given alternatives:
i. What is the percentage of sea/ocean water on earth?
a. 97% b. 79% c. 9% d.7%
ii. Which substance is called universal solvant?
a. Either b. Alcohol c. Water d. all of them
iii. Which salts are responsible for causing hardness of water.
a. Salt of ‘Ca’ & ‘Mg’ b. Salts of Na & ‘K’
c. salts of ‘Be’ & ‘Ca’ d. salts of ‘K’ & ‘Mg’
214 Blooming Science Book 9
iv. The molecules of water are attracted to each. Which property of water is it?
a. solvant b. adhesive c. surface tension d. cohesive
v. How can we remove temporary hardness of water?
a. by using soap b. by boiling c. by filtration d. by treating with salts
2. Answer the following questions.
a) What is the importance of cohesive and adhesive property of water in plant?
b) Write down the physical properties of water.
c) What is meant by hard and soft water?
d) How do you remove the temporary hardness of water? Give chemical equations
also.
e) How do you remove permanent hardness of water? Give chemical equations also.
f) What are the advantages and disadvantages of hard water?
g) Write down the chemical properties of water.
h) What is called permutit?
3. Write with balanced chemical equations, What happens when
a) The water containing calcium bicarbonate is heated?
b) The water containing magnesium bicarbonate is heated?
c) The water possessing permanent hardness is treated with washing soda?
d) The water possessing temporary hardness is treated with lime water?
4. Write differences between:
a) Cohesive and adhesive property
b) Hard water and soft water
c) Underground and surface sources water
5. Write short notes on:
a) Surface water
b) Solvent property of water
c) Capillary action of water
6. Give reasons:
a) Lather is not produced easily by hard water
b) Hard water becomes soft on heating
c) Distillled water is not good to drink
Blooming Science Book 9 215
Chapter MATERILAS USED IN
DAILY LIFE
15
Learning Outcomes Estimated Periods: 5
On the completion of this unit, the students will be able to:
• describe the types and uses of nitrogen, phosphorous and potassium containing
fertilizers.
• differentiate between organic and inorganic fertilizers.
Fertilizer
Plants absorb elements such as Phosphorous, Potassium, Calcium, Boron, Chlorine, Iron, etc.
from soil. This is just like borrowing elements from soil, because the elements are returned to
the soil after the death of living beings. This situation occurs only in the natural ecosystem like
forest. In the cultivated land, the growing plants use the nutrients from the soil. After harvesting
the crop, the nutrients are not returned back to the soil. Repeated growing of the crops consume
a lot of these nutrients from the soil. This results in decreasing in minerals or nutrient from the
soil. Rain water and erosion also decrease nutrients. As a consequence; land fertility decreases
and the growth of the plants as well as their yield become poor. The addition of fertilizers make
up for the loss of these nutrients. Thus, the fertilizers are the substances (chemical compounds)
which are added to the soil to replenish the nutrients removed by growing plants.
The essential elements present in fertilizer must be readily available to the plants. The essential
elements like oxygen, hydrogen and carbon are obtained by the plants from carbon dioxide of air
and water. But to supply the remaining elements, fertilizers have to be used.
Types of Fertilizer 2. Inorganic fertilizers (Chemical fertilizers)
There are two types of fertilizers
1. Organic fertilizers (manures) and
Organic Fertilizer (Manure)
Manure is an organic substance obtained from the decomposition of animal remains, poultry
droppings and dead plants. The function of an organic fertilizer is to provide the necessary
nutrients to plants. There are two types of manures. They are green manures and animal manures.
a. Green Manure: Green manures are the green plants which are highly nutritive. They are
grown in the fields and are ploughed back under the soil to supply nutrients to the soil.
Thus, green manuring is defined as the practice of growing, ploughing under and mixing
of green plants with soil to improve soil fertility and ultimately crops productivity. It also
avoids soil erosion and leaching. There is a possibility of increasing about 30-50% in the
crop yield by using green manure. These dead green plants add organic matter to the soil,
called humus. Most of the leguminous and some non-leguminous plants can be used as
green manure.
216 Blooming Science Book 9
b. Compost Manure: Compost manure is a kind of natural fertilizer which is prepared by
mixing of cattle dung, poultry droppings and crop resides like remnants of the straw,
rotten vegetables, etc. The mixture is stored in a pit. Sometimes, lime is added to the
pit containing mass to make a good kind fertilizer. Gradually, by the action of micro-
organisms, decomposition takes place and converts it into compost. The compost manure
provides most of the nutrients requires by plants and enhances the fertility of soil.
Chemical Fertilizer
A chemical fertilizer is an artificially prepared inorganic chemical compound added to the soil for
making up the deficiencies of primary plant nutrients. Some of the common chemical fertilizers
are urea, ammonium sulphate, ammonium phosphate, potassium sulphate, etc. Chemical
fertilizers are rich in various essential plant nutrients and are soluble in water.
Chemical fertilizers are divided into three common types depending upon the nature of the
primary nutrients they supply to plants. They are nitrogenous fertilizers, phosphorus fertilizers
and potassium fertilizers.
a) Nitrogenous Fertilizers: The fertilizers which contain only salts of nitrogen are called
nitrogenous fertilizers. These fertilizers make up the nitrogen deficiency of the soil. Some
of the common nitrogenous fertilizers are ammonium sulphate (NH4)2 SO4, ammonium
nitrate (NH4NO3), urea CO(NH2)2 and calcium cyanamide Ca(CN)2.
Ammonium nitrate and urea are abundantly used as nitrogenous fertilizers.
Functions of Nitrogen
1. It promotes the fast growth and development of plants.
2. It helps to form a large amount of protein and chlorophyll.
3. It helps to increase yield of crops.
Effects of deficiency of nitrogen
The deficiency of nitrogen causes:
1. Low growth and development of plants.
2. Reduction in crop yielding.
b) Phosphorous Fertilizers: The fertilizers which contain salts of phosphorus are called
phosphorus fertilizers. Some of the important phosphorus fertilizers are ammonium
phosphate (NH4)3PO4, calcium super phosphate Ca (H2PO4)2 and triple super phosphate
3Ca(H2PO4)2 2CaSO4. The phosphorus nutrient can also be obtained from bone meal.
Functions of Phosphorus
1. It helps in proper growth and development of roots.
2. It makes the plant highly resistant to diseases.
3. It helps in maturity of crops and seed formation.
Blooming Science Book 9 217
Effects of deficiency of phosphorus
The deficiency of phosphorus results in:
1. Less growth and development of roots.
2. Reduction in disease resistant power of the plants.
3. Slow rate of cell division.
c) Potassium Fertilizers: The fertilizers which contain only salts of potassium are called
potassium fertilizers. They are also called potash fertilizers. Some of the common
potassium fertilizers are potassium chloride (KCl), potassium nitrate(KNO3), potassium
sulphate(K2SO4) and potassium carbonate(K2CO3).
Functions of Potassium ?DO
1. It helps in proper development of flowers.
You
2. It helps for healthy growth and development NPK fertilizer is a Know
of roots and stalks of leaves. macronutrient but for
the proper growth and
3. It increases the immunity power of plants. development of plants
micronutrients like Mg, Fe,
Effects of deficiency of Potassium Zn, S are also required.
The deficiency of potassium results in:
1. The decrease in the immunity power of plants against diseases.
2. The wilting and withering of leaves.
Chemical fertilizers can be divided into three types on the basis of the number of primary nutrients
they can supply to the plants. They are: single fertilizer, mixed fertilizer and complete fertilizer.
i) Single Fertilizers: These fertilizers which contain only one primary nutrient N2 or K
or P are called single fertilizers. Some of the common examples of single fertilizers are
potassium chloride, ammonium nitrate and potassium sulphate.
ii) Mixed Fertilizers: These fertilizers which contain more than one primary plant nutrients
are called mixed fertilizers. Some of the common examples of mixed fertilizers are
ammonium hydrogen phosphate, potassium nitrate, etc.
iii) Complete Fertilizers: These fertilizers which contain all the three nutrients i.e., nitrogen,
phosphorus and potassium as primary plant nutrients are called complete fertilizers. The
complete fertilizers are also called NPK fertilizers. In fact, NPK fertilizer is a mixture of
more than two fertilizers like the mixture of potassium chloride and ammonium phosphate.
218 Blooming Science Book 9
Differences between Manures and Fertilizers
Manures (Organic) Fertilizers (Inorganic)
1. Organic substance obtained by the
1. They are man-made inorganic salts.
decomposition of dead plants and animals
wastes. 2. They are nutrient specific and so can
be selected to restore deficiency of
2. They are not nutrient specific. specific nutrients in the soil.
3. They are not harmful to the environment. 3. They are harmful to the environment.
4. They are called natural manures. 4. They are called artificial manures.
Disadvantages of using fertilizers
We should not use excessive amount of chemical fertilizers because it causes water and soil
pollution. When nitrogenous fertilizers reach the water body, they cause rapid growth and
development of aquatic plants. They use up available oxygen of the water and create deficiency
of oxygen in water. So, aquatic animals die due to the lack of oxygen. Similarly, when children
drink nitrogen containing water, they become dwarf.
Precautions while using Fertilizers
1. We should not use excessive amount of fertilizers which may damage the plants.
2. Nitrogenous fertilizers having easy burning nature causes fire when they come in contact
with wooden dust, coal, dry leaves, etc.
3. Hydroscopic fertilizers like urea should be stored away from the moist places.
4. Chemical fertilizers should be stored away from the reach of the children.
5. They should be used after testing the soil.
Main Points to Remember
1. Fertilizers are chemicals added to soil, to replace the minerals used by the plants.
2. Fertilizers are of two types. They are organic and inorganic.
3. Chemical fertilizers are chemicals manufactured in industries to form nitrogen,
phosphorous and potassium compounds.
4. Organic fertilizers are made from plants and animals. Compost manure is an example.
5. N, P and K are collectively known as NPK fertilizer. It is a mixed fertilizer.
6. The use of fertilizers has polluted the environment. So the use of chemical fertilizer should
be minimized.
PRO J ECTWORK
Visit the nearby farm or agricultural land and find out the types of fertilizers used in
agriculture and their importance by asking with farmers.
Blooming Science Book 9 219
Exercise
A. Choose the correct answer from the given alternatives.
1. The fertilizer made from chemicals are called..........................
a. Organic fertilizer b. Green manure c. Chemical fertilizers
d. all of them
2. Which one is the example of nitrogenous fertilizers?
a. Urea b. Super phosphate c. Bone meal d. all of them
3. Deficiency of which mineral causes lack of development of flower.
a. Nitrogen b. Potassium c. Phosphorus d. Calcium
4. Which of the following is called organic fertilizer?
a. Insecticides b. compost manure c. urea d. triple super phosphate
5. Which of the following is the complete fertlizer.
a. Nitrogenous b. Potassium c. NPk d. none of them
B. Answer the following questions.
1. What is a fertilizer? Name two chemicals used as fertilizers in the field.
2. What is NPK fertilizer?
3. What is manure? Why are fertilizers used in soil? Name two elements commonly supplied
to plants by means of fertilizers.
4. What are the importance of nitrogen to plants? Name two chemical fertilizers containing
nitrogen.
5. What is super phosphate? What are the plant nutrients present in the fertilizer ammonium
phosphate?
6. Why are phosphorus and potassium (or potash) necessary for plants?. Give two fertilizers
containing potassium?
7. The use of compost manure is far better than the use of chemical fertilizers. Give two
reasons to justify the statement.
8. Distinguish between organic and inorganic fertilizers.
9. Why do farmers use manuer/fertilizer in the field?
220 Blooming Science Book 9
Chapter CLASSIFICATION OF
LIVING THINGS
16
Learning Outcomes Estimated Periods: 8+3
On the completion of this unit, the students will be able to:
• classify plants (upto class) and animals (upto phylum) with their characteristics and
examples.
• describe life cycle of mosquito with diagram.
• make a list of harmful effects of mosquito bite on human beings.
A. Classification of Living Things
Introduction
The surface of the earth is inhabited by a great variety of living organisms. Some of them, such as
amoeba or chlamydomonas are so small that they can be seen only under the microscope. Others
such as the whale or the banyan tree are so huge. A general estimate number of species of living
organisms existing today is more than 5 million. It is therefore very difficult to understand and
remember about each and every living organism. It is more precise to classify them into different
groups on common characteristics shared by all members of that group. Classification is the
arrangement of living beings into different groups on the basis of their similarities.
The great philosopher and biologist Aristotle was the first person to classify living beings into
plants and animals. He also classified all available contemporary animals, so he is called the
“Father of Biology”.
Taxonomy is the branch of Biology which deals with the study of all plants and animals, their
identification and classification. The process of naming living organisms is called nomenclature.
The binomial system of nomenclature was introduced by the great Swedish naturalist Carolous
Linnaeus in 18th Century. He is also known as “Father of Taxonomy.”
Nomenclature is the system of giving proper names to all the unidentified plants and animals
so that these organisms can be distinguished from one another. During 18th century Swedish
naturalist Carolous Linnaeus introduced scientific name of living organism. Every scientific
name consists of two parts, the first generic name i.e. genus and the second specific epithet
i.e. species, it is known as binomial system of nomenclature. Any living organisms having
scientific names of two words in Latin language. In scientific name genus first alphabet is written
in capital letter and species is written in small letter. Scientific name should be underlined or
should be printed in italic. Scientific name of man is Homo sapiens, Rana tigrina (frog), Brassica
campestris (mustard), etc. Living organisms have been classified by different methods. Mainly
living organisms have been divided into two kingdoms i.e. plant and animal kingdom.
The language for genus and species used by Linnaeus is Latin.
Blooming Science Book 9 221
Scientific names of Some Organisms
Common Name Scientific Name
Man Homo sapiens
Frog Rana tigrina
Mustard Brassica campestris
Tiger Panthera tigris
Pea Pisum sativum
Importances of Classification
1. It makes the study of living beings easy and systematic.
2. It helps to study a large group of plants and animals together.
3. It brings out the relationship between one group and another group of plants or animals.
4. It provides a strong support to show that the complex organisms of today have originated
from earlier simplest forms.
Five kingdom system
In junior classes we have learnt that organism can be classified into two kingdom ie plants and
animals. In this chapter we will discuss the five kingdom system which was introduced by an
American taxonomist Robert H. Whittaker in 1969 AD.
Why was five kingdom system introduced?
The five kingdom system was introduced because of the following features.
a) It separates the prokaryotes and eukaryotes
b) It makes the separate group(or kingdom) for green plants and non-green plants.
c) It gives separate kingdoms for unicelluar organism ie morera and protista.
d) Evaluationary history of organism is taken in consideration in this system ie
organism that evolved earlier are place at begining and those evolved later are
last in hierarchy of kingdom.
The five kingdom system includes following kingdoms.
Kingdom Kingdom Kingdom Kingdom
1. kingdom monera 2. Protista 3. Fungi 4. Plantae 5. Animalia
1. Kingdom Monera: In this kingdom primitive unicellular organism with prokaryotic cells are
kept. They contain DNA in the cell but lack nucleus. They are autotrophic and parasitic in nature.
Bacteria, blue green algae, azobactor, etc are examples of kingdom monera.
222 Blooming Science Book 9
2. Kingdom Protista: It consists all oraganisms with eukaryoic unicellular cell. They contain
nucleus in their cell. Paramecium, amoeba, englena, etc are examples. They are mostly parasitic
but some like englena is autotrophic in nature.
Scan for practical experiment
visit: csp.codes/c09e15
3. Kingdom Fungi: It includes non-flowering plants. All the unicellular and multicellular non-
flowering plants like mucor, yeast, mushroom etc fall in this kingdom. The body of fungus is
thalloid, (not differentiated into root, stem and leaf). They are heterotrophic organism. They
absorbs their food from dead and decayed organic matter. Their body store food in the form of
glycogen.
General Characteristics
i) These plants do not consist chlorophyll.
ii) They cannot prepare food materials by themselves. Most of them are saprophytic
others are parasitic or symbiotic.
iii) They grow in damp places or decaying fruits, vegetative and other foods.
iv) Vegetative plant body is called mycelium which consists of several thin, branched,
filamentous like structure which is known as hyphae.
v) Cell wall is made up of fungus cellulose or chitin.
vi) Reproduction takes place by both asexual and sexual methods.
vii) Reserve food material is glycogen and oil.
viii) Yeast is a unicellular but other are multicellular.
Example: mushroom, mucor, yeast, etc.
mushroom Mucor yeast
Blooming Science Book 9 223
4. Kingdom plantae: This kingdom includes large varities of flowering and non-flowering
plants. All the plants in this kingdom contain chlorophyll and are autotrophs. This kingdom is
widely divided into three divisions.
a) Algae: b) Bryophyta c) Tracheophyta
Plantae
Algae Bryophyta Tracheophyta
Pteridophyta Angiosperm Gymnosperm
(a) Algae: These thallophytes are autrophic and contain chlorophyll, but not all algae are
green coloured. They may be of blue, red or brown coloured because of the presence of coloured
pigments. They may be single-celled (Chlamydomonas) or filamentous (Oscillatoria). Most of
the species are aquatic but few are terrestrial being found in damp wall, soil, tree barks and flower
pots.
General Characteristics
1. They are autotrophic due to presence of chlorophyll.
2. The plant body is thallus which may be unicellular or multicellular.
3. They are mostly aquatic, only few species are terrestrial. They may possess
true parenchymatous thallus.
4. The cell wall is made up of cellulose.
5. They reproduce both sexually and asexually.
Examples: Spirogyra, Ulothrix, Chlamydomonas, Oscillatoria, volvox, etc.
Chlamydomonas Spirogyra Ulothrix
224 Blooming Science Book 9
Differences between Algae and Fungi
A1gae Fungi
1. They contain chlorophyll. 1. They do not contain chlorophyll.
2. They are autotropic. 2. They are heterotropic.
3. They grow in well-lighted areas. 3. They usually grow in darker places.
4. The cell-wall is made up of cellulose. 4. The cell -wall is made up of chitin.
5. They store food in the form of starch. 5. They store food in the form of glycogen.
b. Bryophyta: (Amphibian of Plant Kingdom)
General Characteristics
i) Bryophytes are more developed than thallophyta. Some plants of bryophyte are
thalloid but some have stem (axis), leaves (blade) and roots (rhizoids). Rhizoids help
the plant for absorption of water and minerals from soil and mechanical support.
ii) They grow in moist and damp places.
iii) They consist of chlorophyll pigment which helps to prepare food.
iv) Vascular tissue is absent.
v) During life cycle consists of alternation of generation which bears gametophyte
(big and clear) but sporophyte is simple and small.
Scan for practical experiment
Merchantia Funaria Riccia visit: csp.codes/c09e16
vi) Liverworts are leaf like shape, like a leaf attached to soil while growing and rhizoids
are present on the ventral side help in absorption of water and minerals from soil.
vii) Moss is more developed than liverworts. Stem and leaf is well differentiated in
moss plant.
Example: Funaria, Riccia, merchanita.
c) Tracheophyta:
It includes the developed plants. The plants in this category have vascular tssue (xylum
and phloem) so they are also called vasular plants. It is further divided into three sub-divisions:
i) Pteridophyta ii) Gymnosperm iii) Angiosperm
i. Pteridophyta: (First vascular plant)
General Characteristics
i) Pteridophyta is one of the most advanced plants among the non-flowering plants.
Roots (rhizoids), stem and leaf are clearly separated.
ii) They grow mostly in damp and shady places.
iii) Ventral side of the leaf consists of sporangia. Sporangia consists of spores. On
germination spores develop into young plants.
Blooming Science Book 9 225
iv) Embryo is well developed.
v) Life cycle consists of alternation of generation where sporophyte stage is big and
more complicated than gametophyte stage.
Example: fern, horsetail, etc
Horsetail Fern
Differences between Bryophyta and Pteridophyta
Bryophyta Pteridophyta
1. Gametophyte is large and distinct than 1. Sporophyte is large and distinct than
sporophyte. gametophyte.
2. They have no vascular tissues. 2. They have vascular tissues.
3. The main plant body is gametophyte. 3. The main plant body is sporophyte.
4. Examples: Liverworts, Moss etc. 4. Examples: Fern, Horsetail etc.
(ii) Gymnosperm
General Characteristics
1. The seeds of these plants are not covered (they are naked).
2. The leaves are thin and pointed as a needle.
3. The flower are unisexual.
4. Pollination is done by air.
5. Plants are terrestrial. Cycas Pine tree
Usually plants having hard stem are gymnosperms. Cycas and Pinus are the examples of this division.
(iii) Angiosperm
General Characteristics
1. They are highly developed plants.
2. In these plants seeds are inside the fruit.
3. Mostly plants are bisexual. Only few plants are unisexual.
4. The flowers of these plants are well developed. Flower contains ovules and ovary.
Later ovules develop into seeds and ovary into fruits respectively.
5. These plants are pollinated by air, water, insects and animals.
6. Plants may be terrestrial or aquatic.
7. Some of these plants have soft flexible stem while other are hard and strong.
226 Blooming Science Book 9
The minute aquatic plants like Lemna, Pistia, water hyacinth, lotus alongwith coconut, hard nut,
onion, banana, maize, paddy, wheat, pea, papaya, mustard etc. are the examples of this division.
Differences between Gymnosperm and Angiosperm
S.N. Gymnosperm S.N. Angiosperm
1. They are naked seeded plants. 1. They are closed seeded plants.
2. Leaves are narrow and needle shaped. 2. Leaves are broad and flat.
3. Flowers are in the form of cone. 3. True flowers are present.
4. Examples: Pinus, Cycas etc. 4. Examples: Rice, Maize, Pea, Mustard etc.
They are further divided into two classes:
i) Monocotyledon ii) Dicotyledon
i) Monocotyledon Maize plant
• The plants in which seed contains only one
cotyledon are called monocotyledonous plants.
• These plants are found in hills as well as in plain
region.
• Leaves of these plants are long, narrow and with
parallel venation.
• Usually stems are hollow and nodes are in the
form of joints where stem can be easily broken.
• They have fibrous root.
Example: Paddy, wheat, barley, bamboo, maize, Bamboo Plant
onion, Lemna, Pistia, water hyacinth etc.
ii) Dicotyledon Pea plant Mustard Plant
• The plants in which seed contains two
cotyledons are called dicotyledonous plants.
• These plants are found in hilly or plain region.
• Leaves are broad.
• Usually stems are solid and nodes are not in
the form of joints.
• Their leaves have reticulate venation.
• These plants have tap root and secondary
roots.
Example: Gram, bean, mango, pea, lettuce, mustard etc.
Differences between Monocot and Dicot
S.N. Monocot Plants S.N. Dicot Plants
1. The seed has only one cotyledon. 1. The seed has two cotyledons.
2. Their leaves show parallel venation. 2. Their leaves show reticulate venation.
3. They have fibrous root system. 3. They have tap root system.
4. The flowers are trimerous i.e. floral 4. Flowers are either tetra or
parts are three or multiple of three. pentamerous.
5. E.g. Wheat, Rice, Maize etc. 5. E.g. Pea, Mustard, Sunflower etc.
Blooming Science Book 9 227
5. Animalia
Various types of animals are found in this world. Animals are basically classified into two
sub-kingdoms: invertebrate and vertebrate, on the basis of presence or absence of their
back-bones.
Animal Kingdom
Invertebrates Vertebrates (Chordata)
Phylum - Porifera Class - Pisces
Phylum - Coelenterata Class - Amphibia
Phylum - Platyhelminthes Class - Reptilia
Phylum - Nemathelminthes Class - Aves
Phylum - Annelida Class - Mammalia
Phylum - Arthropoda
Phylum - Mollusca
Phylum - Echinodermata
Invertebrates
The animals without backbone are called invertebrates.This group includes wide variety of
simple structure animals. Invertebrate is divided into 8 phyla. They are as follows:
1. Phylum: Porifera (lat. Porus = Pore, ferre = to bear)
General Characteristics
i) The body is multicellular and diploblastic.
ii) They are aquatic and attached to substratum.
iii) The body surface bears numerous pores, called ostia. Water enters through these pores.
iv) A large opening, the osculum is present at the top through which water is thrown
out.
v) Digestion is intercellular (within the cells).
vi) Respiration, excretion and nervous system organs are not developed.
vii) Reproduction takes place by asexual (budding) and sexual ways.
viii) They possess a great power of regeneration.
e.g. Sponge, sycon, etc.
Sponge Sycon
228 Blooming Science Book 9
2. Phylum: Coelenterate (Gk. Koiles = hollow, enteron = intestine)
General Characteristics
i) They are aquatic found in pond, well, sea etc.
ii) Some are attached with the substratum in water, while other are free swimming.
iii) They are multicellular, diploblastic (two layers of cells) animals.
iv) Some of them are plants having branches.
v) A body cavity called coelenterons represents the digestive tube.
vii) Mouth is surrounded by tentacle which helps in locomotion and capturing food. It
absorbs essential components and removes unwanted substances from mouth.
viii) Reproduction takes place by asexual and sexual methods.
ix) Stinging cells are present on their tentacles which help to take food.
x) Respiratory, excretory and circulatory systems are absent.
e.g. Hydra, obelia, corals, jellyfish, etc.
Hydra Coral Jelly fish
3. Phylum - Platyhelminthes (Gk. Platys = flat, helminth = worm)
General Characteristics Scan for practical experiment
i) They are dorsiventrally flat, unsegmented animals.
ii) They are triplobalstic ( 3-layer of cells).
iii) The body cavity or coelom is absent.
iv) They are mostly hermaphrodite. (i.e. having both sexes
within same body)
v) Locomotary organs, respiratory, circulatory systems are visit: csp.codes/c09e17
absent.
vi) Sucker is present around the mouth but anus is absent.
vii) They are bilaterally symmetrical.
viii) Most of them are parasitic and few are free living and attached to stones.
ix) They cause various diseases in mammals.
e.g. Liver fluke, tape worm, planaria, etc.
Liver fluke Tape worm planaria
Blooming Science Book 9 229
Differences between Male and Female Ascaris
Male Ascaris Female Ascaris
1. The male is smaller than female. 1. The female is larger than male.
2. The tail of male is curved. 2. The tail is straight and pointed.
3. In male, genital pore and anus open into a 3. In female, the genital pore and anus
common chamber, the cloaca. open separately.
4. Tail of male is provided with a pair of penial setae. 4. Penial setae is absent.
4. Phylum Nemathelminthes or Aschelminthes
General Characteristics
(Gk. askos = cavity, helminthes = worm)
i) They consist of mouth, anus and sucker.
ii) Most of them are free living and some are parasites on plants and animals.
iii) Most of them are aquatic in fresh water, marine water or terrestrial in soil.
iv) They lack respiratory and circulatory system.
v) These are unisexual, i.e. sexes are separated.
vi) Body can be divided into two equal halves (bilaterally symmetrical).
vii) Alimentary canal is straight with mouth and anus.
viii) Male ascaris is smaller than female.
e.g. Ascaris, hookworm, etc.
Ascaris Hookworm
5. Phylum - Annelida
General Characteristics
i) The animals are having long, cylindrical and segmented body.
ii) They are found on land in moist and damp places.
iii) Body skin is moist and respiration takes place through skin.
iv) Alimentary canal is well developed from mouth to anus.
v) Brain and nerve cells are well developed.
vi) Excretion and blood circulation organs are developed.
230 Blooming Science Book 9
vii) They are hermaphrodite. Leech Earthworm
viii) Body can be divided into two equal halves
i.e. bilaterally symmetrical.
ix) Locomotion is carried out by bristle or setae.
x) Body is triploblastic.
e.g. Earthworm, leech, etc.
6. Phylum Arthropoda (Gk: Arthros = jointed, podos = foot)
General Characteristics
i) It is the largest phylum in animals.
ii) They are terrestrial, aquatic and as well as aerial. Scan for practical experiment
iii) They bear joint appendages.
iv) Body is divided into three parts. i.e. head, thorax and
abdomen. Some are having fused head and thorax. i.e.
cephalothorax.
v) Alimentary canal is well developed from mouth to anus.
vi) Some have wings. visit: csp.codes/c09e18
vii) Sexes are separate.
viii) Mainly four stages in the life cycle. i.e. egg, larva, pupa and adult.
ix) Phylum includes honey bee, ant, millipede, centipede, mosquito, etc.
Centipede Millipede Mosquito
Arthropoda is divided into four classes:
a) Crustacea: They are aquatic. Head is often fused with thoracic segments to form
cephalothoraxes. Respiration through gills or body wall. Jointed appendages, are
present, eg. crab, lobster, cray fish, etc.
Lobster Crab
Blooming Science Book 9 231
b) Insecta: They are terrestrial, body is
divided into three regions head, thorax and
abdomen. They have three pairs of jointed
legs and two pairs of wings, eg. grasshopper,
houseflies, cockroaches etc.
c) Myriapoda: They are terrestrial. Body is
cylindrical and segmented, each segment
bears one of two pairs of legs, eg. centipede,
millipede etc.
d) Arachnida: Mostly are terrestrial. Body is
divided into cephalothorax and abdomen.
There are six pairs of appendages on
cephalothorax, eg. spider, scorpion, etc.
7. Phylum Mollusca: (Lt. mollis = soft)
General Characteristics
i) They have soft and unsegmented bodies.
ii) They are aquatic (fresh water or marine) and terrestrial.
iii) Some animal’s body is covered by hard shell which is made up of calcium. They
have muscular feet for locomotion but in octopus tentacles help in locomotion.
iv) Head of some animals may consist of tentacles.
v) They are very sensitive to external stimuli like touch.
vi) Digestive, blood circulatory, excretory and nervous systems are well developed.
vii) They are mostly unisexual.
viii. The body is usually divided into head, visceral mass and muscular foot. e.g.
octopus, snail, slug, cuttle fish, unio, etc.
Octopus Snail Cuttle fish
8. Phylum Echinodermata (Gk; Echino = spiny, derma = skin)
General Characteristics
i) Body is covered with spine which is made up of calcium carbonate. These spines
are very hard and are found on the dorsal side of body.
ii) They are aquatic and found in sea.
iii) They are unisexual.
232 Blooming Science Book 9
iv) They have radially symmetrical body.
v) Star fish consists of five arms which looks like a star.
vi) A distinct head is absent and mouth lies on the ventral surface.
vii) Feeding and locomotion takes place by the tube feet.
e.g. starfish, sea urchin, sea cucumber etc.
Starfish Sea urchin
Phylum-Chordata
Phylum chordata includes all types of animal with backbone. Fish, frog, lizard, bird, dog, cat,
human all come under this phylum. Though there are variations in characteristics of these animals,
they have some similarities in their morphological features.
Characteristics of chordata
1. Just below the spinal cord is a flexible tube like body called the notochord developed at
any stage of their life.
2. The space in the vertebra of back bone is filled with dorsal tubular nerve cord.
3. A part of the body, containing the notochord or vertebral column projects to form a tail. In
some cases it is limited only in their embryonic stage.
4. The external pharyngeal region of all embryonic chordate bears a series of gill clefts.
5. In these animals the skull is developed and the internal skeleton is covered by muscles.
6. Closed type of cirulatory system is developed.
Phylum chordata is fruther divided into four sub-phylum; hemichordata, urochordata,
cephalochordata and vertebrata.
a. Sub phylum: Hemichordata: The animals posses notochord in their anterior region of
their body. eg. Balanoglossus.
b. Sub-phylum: Urochordata: The notochord is present in the tail region of he larval stage
only but not in the adult, e.g. Polycarpa, Hardmania, etc.
c. Sub-phylum: Cephalochordata: The animals belong to this sub phylum has notochord
that extends from anterior end to the posterior end of the body, e.g. Amphioxus,
Branchostoma, etc. The subphyla hemichordata, urochordata, and cephordata are called
protochordata jointly. The have bone but no back bone in their body.
Blooming Science Book 9 233
d. Sub-phylum Vertebrata
The main sub-phylum of chordata is vertebrata. Therefore it is discussed here.
Animals having backbones belong to this group.
1. These animals are found in water and on land.
2. Their bodies are bilaterally symmetrical (can be divided into two equal parts from an axis).
3. Some of them respire through gills while most of other respire through lungs.
In some of these animals the body temperature changes according to environment. They are
called Poikilothermic (cold-blooded). For example: fish, frog, snake etc. In homoeothermic
(warm blooded) animals, body temperature does not change according to the environment. For
example; Bird, monkey, human being etc.
Sub-phylum vertebrata is classified into five classes. They are:
(a) Pisces (b) Amphibia ?Do
(c) Reptilia
(e) Mammalia (d) Aves Sea horse is the only creature You
where male gives birth to its Know
a. Pisces young ones ie, male produces
babies not the female.
General Characteristics
1. They are the most primitive and aquatic vertebrates with a streamlined body.
2. Body is covered with water-proof scales.
3. Body is divisible into head, trunk and tail.
4. They have gills for respiration..
5. They have fins to swim.
6. They have two-chambered heart. Fish Shark
7. They lay eggs i.e. they are oviparous and fertilization is external.
8. They are cold-blooded animals. Sea-horse
Examples: All kinds of fishes like Asla, Rohu, Shark, Sea-horse etc.
b. Amphibia
General Characteristics
1. They live in water during larval stage and live both on land and in water in the adult stage.
2. Skin is soft and moist.
3. They have two pairs of limbs which enable them to walk and jump on land and swim in water.
4. Body is usually divisible into head and trunk.
5. Gills are the respiratory organs in tadpoles. Skin and lungs are the respiratory organs in adult.
6. They lay eggs and fertilization is external.
7. They have three-chambered heart.
234 Blooming Science Book 9
8. They are cold-blooded animals.
Examples: Frog, Toad, Salamander etc.
Frog Salamander Toad
Reptilia
General Characteristics Scan for practical experiment
1. They creep or crawl on the land.
2. They are mostly terrestrial and some are aquatic.
3. Skin is dry, non-glandular and covered with hard scales.
4. Body is divisible into head, trunk and tail.
5. They have two pairs of limbs except snakes. visit: csp.codes/c09e19
6. Lungs are the respiratory organs.
7. They have generally three-chambered heart but the crocodile has four-chambered heart.
8. They lay eggs on land and fertilization is internal.
Examples: Wall lizard, Garden lizard, Snakes, Crocodile, Turtle, Tortoise etc.
Crocodile Turtle Wall lizard Snake
Aves
General Characteristics
1. They are aerial animals. Most of them fly except Ostrich, Kiwi, Penguin etc.
2. Their body is covered with feathers.
3. Forelimbs are modified into wings for flying. Hind limbs are in the form of legs and are
variously modified for walking, perching, swimming and so on.
4. Mouth is modified in the form of beak and teeth are absent.
5. The bones are light, hollow and spongy i.e. they possess pneumatic bone.
6. Body is divided into head, neck, trunk and tail.
7. They have four-chambered heart.
8. Lungs are the respiratory organs.
Blooming Science Book 9 235
9. They lay eggs (oviparous) and fertilization is internal.
Examples: Danphe, Pigeon, Sparrow, Duck, Crow, Parrot, Dove, Hen, Ostrich, Penguin etc.
Pigeon Duck
Mammalia
General Characteristics
1. They are the most developed animals.
2. Females have mammary glands which produce milk to suckle their young ones.
3. Body is covered with hair.
4. They possess a pair of external pinna on the head.
5. They have four limbs generally each with five digits.
6. Lungs are the respiratory organs.
7. Heart is four chambered.
8. They give birth to young ones (viviparous) and fertilization is internal.
9. They are aquatic (Whale), terrestrial (Man) and aerial (Bat).
Bat Whale Cow
Examples: Man, Cow, Monkey, Bat, Squirrel, Rabbit, Porcupine, Mouse, Hare, Dolphin, Whale
etc.
Let’s Learn
1. Bryophytes are called amphibian plants because they require water for fertilization.
2. Ferns are known as vascular cryptogams because they contain vascular tissue, the xylem
and phloem as well as they do not bear flower at all.
3. Jellyfish is not a fish because its body does not consist of a gelatin. It belongs to phylum
coelenterate. It is of an umbrella shaped with four arms which help it to swim in water like
fish so it is called jelly fish.
4. Pine is gymnosperm because it has seeds outside the fruits.
5. Fruits are not formed in gymnosperms because double fertilization does not occur in them.
6. Mustard is a dicotyledonous plant because it has two cotyledons in its seeds.
7. Bat is not a bird but a mammal because it has hair on its body and gives birth to its young
ones and suckles them on milk produced by milk glands of the female bat.
8. Birds are called warm-blooded animals because the temperature of the birds does not vary
with environmental temperature.
9. Fish and frog are called cold-blooded animals as their body temperature is not constant
i.e., the body temperature varies with environmental temperature.
236 Blooming Science Book 9
Classification of some plants and animals (on the basis of five kingdom with a distinguishing
character)
1. Fern 7. Cycas
Kingdom
Kingdom : Plantae Division : Plantae
: Tracheophyta
Division : tracheophyta Sub-division
Example : Gymnosperm
Sub-Division : Pteridophyta : Cycas
Eg. fern
Roots (rhizoids), stem and leaf are clearly
separated and life cycle consists of
alternation of generation.
2. Pinus 8. Amoeba
Kingdom : Protista
Kingdom : Plantae Eg. Amoeba
It is unicellular microscopic in which
Division : Tracheophyta
locomotion takes place by pseudopodia.
Sub-Division : Gymnosperm
Type : Pinus
It has naked seeds.
3. Liverwort 9. Sea horse
Kingdom
Kingdom : Plantae Phylum : Animalia
Sub-phylum : Chordata
Division : Bryophyta Class : Vertebrata
: Pisces
Genus : Marchantia Type : Sea horse
It grows in moist and damp places.
4. Mushroom 10. Jelly fish
Kingdom : Fungi Kingdom : Animalia
It grows by spores in rotten log of woods. Sub-division : Invertebrata
Phylum : Coelenterate
Type : Jellyfish
It is the coelenterate which has a body
cavity called coelenterons that represents
digestive system.
5. Mustard 11. Crayfish
Kingdom : Plantae Kingdom : Animalia
Division : Tracheophyta Sub-kingdom : Invertebrate
Sub-division : Angiosperm Phylum : Arthropoda
Class : Dicotyledon Class : Crustacea
Example : Brassica comperstris Type : Crayfish
Body is triploblastic, bilaterally
symmetrical and divisible into head,
thorax and abdomen.
6. Maize 12. Human being
Kingdom
Division : Plantae Kingdom : Animalia
Sub-Division : Tracheophyta
: Angiosperm Phylum : Chordate
Class :Monocotyledon
Example : Zea mays. Sub - phylum : Vertebrata
Class : Mammalia
Example : Homo sapiens
Blooming Science Book 9 237
Main Points to Remember
1. Classification is the arrangement of living beings into different groups on the basis of their
similarities.
2. Taxonomy is the branch of Biology which deals with the study of all plants and animals,
their identification and classification.
3. Nomenclature is the system of giving proper names to all the indentified plants and
animals so that these organisms can be distinguished from one another.
4. Living things are mainly divided into 5 kingdoms: Plantae, Animalia, Monera, Protista
and Fungi.
5. Kingdom plantae is divided into 3 division: Algae, Bryophyte and Tracheophyta.
6. Sub-Divisions Gymnosperm, Angiosperm and Pteridophyta belong to Tracheophyta..
7. Class monocotyledon and dicotyledon belong to angiosperms.
8. Bryophytes are called amphibian plants.
9. All animals of animalia kingdom are divided into two groups - invertebrates and vertebrates.
10. Invertebrates group includes 8 major phyla = porifera, coelenterate, platyhelminthes,
nemathelminthes, annelida, arthropoda, mollusca and echinodermata.
11. Vertebrates group includes only one phylum chordate.
12. Phylum chordate is further classified into five classes pisces, amphibian, reptilia, aves and
mammalian.
13. Animal with back bones are kept in phylum-chordata and sub-phylum-vertebrata.
Vertebrata includes pisces, amphibia, reptilia, aves and mammalia.
14. Pisces, amphibia and reptilia are cold blooded.
15. Aves and mammalia are warm blooded animals.
16. The animals which lay eggs are oviparous and which give birth to their young ones are
called viviparous.
PRO J ECTWORK
Collect some plants/branches/leaves from your locality. Make them dry by keeping in the
folds of news paper for some days and make the herbarium collection.
Exercise
1. Choose the correct answer from the given alternatives.
i. Who is known as father of taxonomy?
a. R.H Whittaker b. C. Linnaeus c. Carl Woese d. E. haeckel
d. invertebrates
ii. Pinna is the characteristic of
a. mammels b. vertebrates c. chordates
iii. Fruit is absent in
a. mango b. rose c. cycas d. sunflower
238 Blooming Science Book 9
iv. The elastic cord present in the chordates above the alimentary canal is
a. notochord b. vertebral colum c. backbone d. spinal cord
v. Which one of the following is called a vascular non-flowering plant?
a. marchantia b. cycas c. fern d. spirogyra
2. Answer the following questions.
a. Who is called Father of Biology? Why?
b. What is taxonomy? What do you mean by binomial system of nomenclature?
c. Give any three importances of classification.
d. Why are the bryophytes called amphibian plants?
e. Give general characteristics of algae with suitable examples.
f. Name the organism given in the diagram and give its two characteristics.
Name other two organisms of the same category.
g. In between algae and moss plants, how do you distinguish algae? Write its three important
characters.
h. Write the main characteristic features of phylum arthropoda.
i. Make a classification chart of plants with an example of each.
j. Write four characteristics of phylum chordata.
k. Write three main characteristics of sub-phylum vertebrata.
l. Write three major characteristics of mammals.
m. Draw tree sketch of vertebrates.
m. Cold blooded and warm blooded
3. Differentiate between:
a. Bryophyte and Pteridophyte b. Algae and Fungi
c. Angiosperm and gymnosperm d. Earthworm and round worm
e. Vertebrates and invertebrates f. Horse and horse tail (equisetum)
4. Classify the following organism. Also write one general characteristic of each of the
plant or animal.
Horsetail Mango Ascaris
Ulothrix Hydra Rohu
Sea-urchin Marchantia Frog
Liver fluke Coral Snake
Mucor Cricket Dove
Unio Sponge Bat
Crab Leech Bamboo
Blooming Science Book 9 239
5. Identify the phyla of animal or division of plant with the given salient features.
a. Diploblastic, multicellular, fixed, aquatic, body with numerous pores.
b. Multicellular, having tentacles, diploblastic body with a coelenterons.
c. Locomotion by pseudopodia.
d. Body is flat, sucker is present about the mouth.
e. Having shell made up of calcium carbonate to protect itself.
f. Radially symmetrical, unisexual, having tube feet, exclusively marine.
g. Body is elongated, segmented and hermaphrodite.
h. Found in damp places having alternation of generation in the life cycle and develop embryo.
i. Absence of chlorophyll, heterotroph, parasite.
j. Body is covered with hard substance called chitin and has jointed appendages.
k. It neither gives flower nor has distinct root, stem and leaves.
l. Amphibian plants, liver shaped plant body, autotrophic, alternation of generation
(gametophyte is dominate over sporophyte).
6. Classify the organism shown in the diagram.
240 Blooming Science Book 9
B. Life Cycle of Mosquito
Mosquito Due to climate change, mosquitos ?DO
are seen even in Mustang these
Habit and Habitat days . Just 3 decades ago they You
were seen only in terai region of Know
Mosquitoes are found in damp & marshy our country.
places in tropical & sub-tropical region.
There are nearly 300 species of mosquitoes
out of which 100 species are the vectors of diseases. They can fly over the large distance
continuously for 2-3 hr and cover the distance of 20-30 km.
Mosquitoes are found in different parts of the world. Mostly they are Scan for practical experiment
found in tropical and temperate regions of the world where the climate
is hot. There are several different varieties of mosquitoes which are visit: csp.codes/c09e20
found in different places like house, gardens, drains, ponds, fields, etc.
in monsoon and in spring season. They are generally active during
night and search for the food. Mainly male mosquitoes feed on the sap
of plants and female mosquitoes suck the blood of animals to survive.
These female mosquitoes are also carrier of several dangerous diseases
such as malaria, filariasis, yellow fever, meningitis, encephalities, etc.
Classification
Kingdom - Animalia Wings
Sub Kingdom - Invertebrate
Hind leg
Phylum - Arthropoda Antennae
Sub Phylum - Mandibulata
Class - Insetcta Thorax Abdomen
Type - Mosquito Fore leg Middle leg
Body Structure
Mosquitoes are small insects. Their body is soft, covered with scales, slender having wings and
is about 3 to 6 mm long. The body is divided into head, thorax and abdomen.
1. Head: It is small, round, mobile and is connected with thorax having a short neck. It
consists of a pair of compound eyes and a pair of antennae. Mouthpart is piercing and
sucking type. In between antennae their arise a long proboscis which is formed by the
fusion of labium. It ends in a pair of pointed lobes which are well developed in female
mosquitoes. The male cannot suck blood and they feed on only juices of flower and fruit.
2. Thorax: It consists of three parts. i.e. prothorax, mesothorax and metathorax. A very small
is prothorax, a very large mesothorax and a small metathorax. A pair of wing is attached
on the mesothorax region. The wings are larger in female than in males. The wings of the
mosquitoes produce sound during flight. There are three pairs of legs which are attached
to the thorax. The metathorax bear a pair of process called halters or balancers.
Blooming Science Book 9 241
3. Abdomen: It is long and narrow. There are nine segments in abdomen. The anus is situated
in the eighth and genital pore is in the nineth segment.
Types of Mosquito
There are different types of mosquitoes. Culex and the anopheles are two common mosquitoes
which are found in Nepal. They can be easily distinguished by the following ways.
Culex Anopheles
1. Wings are transparent, uniformly 1. The wings are light coloured, spotted and
coloured, slightly bend, can fly for a long cannot fly for a long time.
time. 2. Maxillary palps are equal in length with
2. Maxillary palps are shorter in female but the proboscis in both sexes.
longer in male than the proboscis. 3. While rest it makes horizontal with the
3. At rest, body is parallel with the surface. surface.
4. It transmits filariasis disease, meningitis, 4. It transmit malarial disease, lymphatic
encephalitis, etc. filariasis, etc.
Life Cycle of Mosquito
Mainly mosquitoes are seen on land but egg, larva and pupa stages are completed in water.
Adult stages are found on land. There are four stages in the life cycle i.e. eggs, larva, pupa and
adult. This is known as metamorphosis. The females usually mate only once but produce eggs at
different intervals through out their life.
Adult Adult
Pupa
Eggs Eggs
Pupa
Larva Larva
Fig: Life cycle of Culex Fig: Life cycle of Anopheles
(a) Eggs: After mating, the female lays eggs on water. Mainly female mosquitoes lay eggs on
stagnant lake, pond, drains, etc. Anopheles lay eggs on fresh water and culex in dirty
water. One anopheles mosquito lays 40 to 100 eggs at a time and eggs are not attached
with each other and float on the surface of water which are boat shaped. But culex female
mosquito lays approximately 300 eggs in one time and are attached with each other which
float in cigar shaped structure.
(b) Larva: When the environment is suitable in 2-3 days, the egg Larva
hatches into transparent larva which measures 1mm in length
and feeds on algae which are in water. At this stage larva eats a
lot so they are also called voracious feeders. Its body is divided
into head, thorax and abdomen. The head is big and separated
from the thorax by a narrow constriction. Head bears a pair of
compound eyes. Small hairs help them to take food from water to
242 Blooming Science Book 9
mouth. Thorax and abdomen also consist of small hair or bristles structure. The abdomen is
long, slender, with nine segments. There is presence of respiratory siphon in eighth segments
which helps in breathing in ninth segments bears tracheal gills. The larva of anopheles hangs
horizontally with head parallel to the surface of water, while the larva of culex hangs with
head downward making an angle with the surface of water.
Larva of mosquito grow in four stages called instars. In first in star length becomes 1.5 mm
and fourth in star is about 8-10 mm. It swims in water by wriggling movement so they are
also termed as wriggler.
(c) Pupa: After a week, when the larva gets suitable temperature and food it changes into
pupa. The body consists of cephalothorax which is combination of head and thorax, and
an abdomen. Abdomen is slender, curved and segmented. Two respiratory trumpets by
which it respires. Trumpets are similar to siphon. Mosquito pupa is active but takes no
food due lack of mouth and anus. Pupa is enclosed in a transparent membrane called
puparium. The pupa stages last for 2-7 days. The process of changing pupa inside the
puparium is called histogensis. The pupa of mosquito is commonly termed as tumbler.
(d) Adult: After few days, adult mosquito emerges out from the puparium membrane having
the development strong legs and wings called imago.
Note:
Moulting: The periodic shedding of the outer layer of the skin of larvae of insects to allow
further growth is called moulting.
Histogenesis: Differentiation of tissues inside the puparium of insects is called histogenesis.
Metamorphosis: Period of rapid transformation from larval to adult stage is called metamorphosis.
Diseases Transmitted by Mosquitoes
Mosquitoes are responsible for transmitting several diseases like malaria, filariasis, yellow fever,
meningitis, encephatlitis, dengue etc.
Malaria
The disease malaria is caused by microscopic protozoan called Plasmodium vivax and is transmitted
by female anopheles mosquitoes. Mosquitoes are the carriers of this disease. When a female anopheles
mosquito sucks the blood of an infected person many malarial parasites are sucked with the blood.
Plasmodium has two hosts i.e. man and mosquito. Man is regarded as the primary host, while female
anopheles as the secondary host. When an infected female anopheles bites a healthy person to suck the
blood, the saliva having thousands of Plasmodium vivax enter the blood of a healthy man. From the
way of blood, parasites reach into the liver of a man. They remain for two weeks in liver and increase
their numbers. After that again return back to blood and enter inside red blood cell, increase its size into
amoeboid shape and numbers. After that infected RBCs burst and release the parasites into the blood.
These parasites repeat the process of life-cycle by entering into the fresh RBCs. As a result, the infected
person suffers from fever. If treatment is not done in time, it may cause the death of the patient.
Blooming Science Book 9 243
Control of Mosquitoes
Mosquitoes transmit several harmful diseases. Mosquitoes should be killed to be safe from
malarial disease. There are several methods of controlling the mosquitoes.
1. The mosquito bites can be avoided by using mosquito net during sleeping.
2. Larva and pupa develop in water so in dirty stagnant water paraffin or kerosene oil should
be used by which larva and pupa die due to blockage of respiration.
3. Swamps and stagnant water should be drained away to avoid the breeding area of
mosquitoes.
4. Mosquitoes can be controlled by spraying DDT. DDT and insecticides destroy the eggs,
larvae and pupae.
5. During sleep apply mustard oil or mosquito repellent cream on exposed parts.
6. They can be controlled by using Gambusia fish which feed on egg, larva and pupa of
mosquito.
7. Eliminate the breeding area of mosquitoes.
Activity
Method of Controlling Mosquitoes
Materials required: beaker, petridish, water, edible oil or kerosene oil, mosquito larva or pupa.
Method:
1. Take one beaker or petridish with water and few mosquito larva and pupa.
2. Observe these larva and pupa hanging on the surface of water. They dive inside water
when the water is disturbed.
3. Keep the water undisturbed for a while and put 1-2 drops of edible oil or kerosene oil.
4. Observe the condition of larva and pupa how useful is this method of removing
mosquitoes?
Differences between Male and Female Mosquitoes
Male Mosquito Female Mosquito
1. Male mosquitoes only fed on sap of plant. 1. Female mosquitoes bite and suck blood.
2. Antenna is provided with long hairs. 2. Antenna is provided with short hairs.
3. Mouth parts are adapted for sucking. 3. Mouth parts are adapted for sucking and
biting.
4. Abdomen is smaller. 4. Abdomen is large.
244 Blooming Science Book 9
Comparision of life cycle of Anopheles and Culex Mosquitoes
Anopheles Culex
1. Egg 1. Egg
(a) Each egg is boat-shaped and floats (a) Each egg is pointed at one end and
separately. broad at the other. The eggs are glued
(b) Female lays 40-100 eggs at a time. together to form rafts which float.
(c) Eggs are laid singly. (b) Female lays 200-300 eggs at a time.
(c) Eggs are laid together in a floating mass.
2. Larva 2. Larva
(a) Larva floats on the surface of water. (a) Larva hangs its head downwards
(b) The respiratory tube is short and wide. inclined at an angle to the surface of
water.
(b) The respiratory tube is long and conical.
3. Pupa 3. Pupa
(a) Pupa is green in colour. (a) Pupa is colourless.
(b) It has short respiratory trumpets. (b) It has longer respiratory trumpets.
4. Adult 4. Adult
(a) Its body is slender with delicate leg. (b) Its body is stouter with thicker legs.
(b) Wings have spot on them. (c) There are no spots on the wings.
(c) Body at acute angle with the surface on (d) Body more or less parallel to the surface
which it rests. on which it rests.
Let’s Learn
1. Spraying kerosene on stagnant water helps to control mosquitoes because they form a thin
film of oil over the water which blocks the respiratory lobe of the larvae and pupae and
they die.
2. Male mosquitoes do not bite us because they do not have piercing organs but only sucking
organs.
3. Culex join their eggs with glue each other, which helps the eggs to float to get suitable
light and heat for their proper growth.
4. Disease is transferred by female mosquitoes because only they have well developed
proboscis, which help them to bite and suck the blood. Thus, only female mosquitoes can
transfer the germs.
5. We can control mosquitoes by avoiding stagnant water because the adult mosquitoes lay
eggs in it. The development of larvae and pupae also takes place in stagnant water.
Main Points to Remember
1. Anopheles and culex are two kinds of mosquitoes.
2. Mosquitoes are harmful insects. They are generally active during night and are nocturnal
in feeding habit.
Blooming Science Book 9 245
3. The body of mosquito can be divided into head, thorax and abdomen.
4. Life cycle of mosquito has four stages and they are egg, larva, pupa and adult.
5. Female anopheles lays 40-100 eggs in a lot and female Culex about 300 eggs.
6. Pupa of mosquito is active, can swim a lot, respires with the help of siphon, unlike the
pupa of other insects.
7. Mosquitoes transmit several diseases like malaria, filariasis, dengue fever etc.
8. Malaria is caused by Plasmodium vivax. Female anopheles are the carriers of malaria.
9. The best way to prevent from malaria is to protect from mosquito bite.
10. It is easier and more convenient to kill the mosquitoes in their earlier aquatic stages.
11. Only female mosquito bites us because she needs blood as meal to lay eggs. She is the
carrier of germs that cause disease.
PRO J ECTWORK
Draw the life cycle of mosquito (anopheles and culex) in a chart paper and keep it in your
study room/class room.
Exercise
1. Classify mosquito with any three features.
2. What are the foods of mosquitoes? Do you think male and female mosquitoes take same food?
3. Write differences between anopheles and culex mosquitoes.
4. How malaria disease is transmitted by mosquito? Write preventive measures of this disease.
5. Differentiate between-
a) Egg of anopheles and egg of culex
b) Larva of anopheles and larva of culex
c) Adult anopheles and culex mosquito
6. What is life cycle? Why is it necessary to know the life cycle of mosquito?
7. Female mosquito is more harmful than male mosquito, why?
8. How can mosquitoes bite be avoided? What happens to mosquito larvae if oil or kerosene
is sprayed in water containing them?
9. Female mosquito feeds on blood in addition to nectar of flower, why?
10. Why is water essential to complete the life cycle of a mosquito?
11. What is the pupa of mosquito called? Write down two characteristics of pupa of mosquito?
12. Which type of mosquito transmits filarial? How does the cleaning of puddles help to
control mosquitoes?
246 Blooming Science Book 9
13. Name the stages which spend in water in the life cycle of mosquito. On what factors the
pupa of mosquito is different from the pupa of other insects?
14. The drawing on the side represents a stage in the life cycle of a common insect.
i) Write the name of insect and stage of the life cycle.
ii) Name the place where the pupae of the insect grow.
iii) Mention two ways to control the insect.
iv) Write down the name of disease that is transmitted by the same insect.
15. Give the name of the malarial parasite. How is the malaria caused?
16. What does mosquito larva feed on? Where does mosquito mating occur?
17. Mosquitoes can be controlled if stagnant water around the house is removed, how?
18. Explain the life cycle of mosquito with well-labelled diagram.
19. A type of mosquito lays eggs separately. Name the type and mention any two characteristics
of its larval stage. How can this mosquito be eradicated?
20. Study the given pupa of anopheles and culex and answer the following questions:
(a) (b)
(i) Write any two differences between them in the context of their colour and respiratory
trumpet.
(ii) What are the colour of (a) and (b)?
(iii) What do they eat in this stage?
(iv) Which one of them grows to that mosquito which causes malaria?
Blooming Science Book 9 247
Chapter ADAPTATION OF ORGANISMS
17
Learning Outcomes Estimated Periods: 5+1
After the completion of this unit, the students will be able to:
• describe terrestrial and aquatic adaptation of animals and plants with examples
• introduce micro organisms like virus, bacteria, fungi and protozoa and make a list
of diseases caused by these.
A. Adaptation of Organisms
Introduction
A species makes every effort to adapt to the surrounding environment for its growth. It ensures its
own protection against adverse conditions of its habitat. This is accomplished by the development
of some characteristics (morphologically in most cases). Any feature of the organism or its parts
which is of definite significance in allowing that organism to exist under the conditions of its
habitat is called adaptation.
In simple words, adaption is the adjustment of an organism (plant or animal) in a biological
system or habitat by bringing changes morphologically or physiologically. The living organisms,
i.e. the plants and animals equip themselves in different ways to cope up with their environment.
The animals like dinosaurs, mammoths and saber toothed tigers became extinct from the earth
because they could not adapt to the changing environment. Similarly, plants like large ferns and
mosses became extinct from the earth.
Aquatic and terrestrial organisms develop several adaptive features according to their habitat and
environment.
Aquatic Adaptation
The plants that grow in or on the surface of water or even on swampy or marshy habitats
containing little more water required for a normal plant to grow are called aquatic plants. They
survive in water, respire through oxygen dissolved in water and the light that penetrates helps in
gaining heat and synthesizing food. Aquatic plants are of three types. They are:
(a) Freely floating: e.g. Water Hyacinth, Water lily, Lotus. They remain floating in water ie
root is not fixed with soil.
(b) Submerged: e.g., Hydrilla, Vallisneria. they are fully emerged in water but root is not fixed
with soil.
(c) Fixed (rooted) and emergent: e.g. Sagittaria, Rananculus, water Lily, Lotus . Their some
parts is out of water but root is fixed in a soil.
248 Blooming Science Book 9
Adaptational Features of Aquatic Plants
1. Root system of plants is poorly developed in hydrophytes.
2. The leaves are small, slender and elongated. Example, Hydrilla, Vallisneria, etc.
3. The leaves and other parts of aquatic plants are covered with waxy material that prevents
free passage of water in the plant body, e.g. Lotus, Water Hyacinth, etc.
4. Air sacs and air storage tissues help them to float in water. Presence of aerenchymatous
tissue is a special adaptative feature.
5. They possess weak flexible stems that help to bend easily.
6. The leaves of submerged plants are small whereas the leaves of freely floating are large.
eg: lotus
7. Stomata are present only on the upper surface of the leaves of freely floating plants.
Water Hyacinth Hydrilla Lotus
Adaptational Features of Aquatic Animals
Animals which grow survive and sustain their life in water are called aquatic animals.Eg fishes,
shark, whale, duck, tortoise etc.
They have the following important features:
1. The aquatic animals are streamlined, head is short and possess a long tail. Outer surface is
smooth and thin. The body is covered with water proof scale.
2. Air-sacs in these animals help them float in water.
3. The fins help in swimming, running and changing directions.
4. Gills are the chief respiratory organs that separate oxygen dissolved in water for respiration.
5. The body temperature of aquatic animals change according to the change in temperature
of the surrounding.
Gills
Mouth
Blooming Science Book 9 249
Terrestrial Adaptation
Plants growing on land are called terrestrial plants. Terrestrial plants are further classified as:
(a) Mesophytes: Rose, Mango, Papaya, etc.
(b) Xerophytes: Cactus, Opuntia, Aloe-vera, Euphorbia, etc.
(c) Epiphytes: Orchids, Bromeliads, etc.
Adaptational Features of Terrestrial Plants
1. Roots are well developed in terrestrial plants.
2. Plants of dry land or xerophytes are small, short, bushy possessing thick barks that prevent
transpiration. The leaves are small and thick cuticle on its both the surfaces. Most of the
plants possess thorns which are the modification of leaves.
3. The plants, in the region of enough water available, are well developed.
4. The plants in the dry places have fleshy vascular stem which stores water. The stem is
green to prepare food. They prevent transpiration, the stem has wax or thick cuticle.
5. Climbers possess tendril, hook and aerial root for support.
6. Gymnosperm of high altitude plants are cone shaped with flower modified into cones.
They have foliage leaves for photosynthesis and bracts for protection against snowfall.
Cactus Aloe
Adaptational Features of Terrestrial Animals
The animals living on different climate, altitude differ with each other in great respect.
Terrestrial animals or animals of land can be categorized as:
(a) Terrestrial animals of cold places: e.g. Yak, Polar bear, etc.
(b) Terrestrial animals of warm places: e.g. Buffalo, cow, horse, etc.
(c) Terrestrial animals of desert (xeric animals): e.g. Camel, Lizard, etc.
1. The legs and phalanges of terrestrial animals are modified according to their prey habit,
habitat and climate. Some of them have single hoof whereas some have double hooves.
The legs of animals such as tigers, bears, cats, dogs, etc. have claws.
250 Blooming Science Book 9
The words you are searching are inside this book. To get more targeted content, please make full-text search by clicking here.
Blooming Science-9-2077 final final for press
Discover the best professional documents and content resources in AnyFlip Document Base.
Search