reproduction - class 10th

8/20/2019 Reproduction - Class 10th

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REPRODUCTION

The production of new organisms from the existing organisms of the same

species is known as reproduction.

Reproduction is essentia for the sur!i!a of a species on this earth.

Reproduction gi!es rise to more organisms with the same "asic characteristics as

their parents.

Types of Reproduction

There are two main methods of reproduction in i!ing organism#

Most of the plants reproduce by

reproducing seeds to grow more

plants

Humans reproduce by giving

birth to babies

Dogs reproduce by

giving birth to puppies

Chicken is hatched from Tiger cubs are born from

their mother tigress



$i% asexua reproduction$ii% &exua reproduction.

Asexual reproduction The production of new organisms from a singe parent without the in!o!ement

of sex ces is caed asexua reproduction. &ome of theexampes of asexua reproduction are# "inar' (ssion in )moe"a* "udding in

+'dra* spore formation in Rhi,opus fungus* regeneration in Panaria*

fragmentation in &pirog'ra and !egetati!e in -owering pans.

exual reproduction

The production of a new organism from two parents "' making use of their se

ces is caed sexua reproduction.

The humans (sh frogs hens cats dogs cows horses deer ra""its ions and

tigers

) reproduce "' the method of sexua reproduction. /ost of the -owering pants

aso reproduce "' sexua reproduction.

The "asic di0erence "etween asexua and sexua reproduction is that on' one

parent is needed in sexua reproduction whereas two parents are needed in

sexua reproduction.

A!"#A$ R!%R&D#CT'&(

)n asexua reproduction takes pace "' six di0erent methods. These are#

1. 2ission3. 4udding5. &pore formations6. Regeneration7. 2ragmentation8. 9egetati!e Propagation.

)''&(

In the process of (ssion a uniceuar organism spits to form two the new

organisms.



*inary )ission

4inar' (ssion the parent organism spits to form

two new organisms. The uniceuar organisms ike

amoe"a paramecium eishmania "acteria etc.

reproduce "' "inar' (ssion.

)moe"a reproduces "' "inar' (ssion. The two

daughters )moe"a produced here grow to their

fu si,e "' eating food and then di!ide again to

produce for )moe"ae and so on. In the uniceuar

organisms such as )moe"a the spitting of the Parent ce during

(ssion can take pace in an' pane.Paramecium aso reproduces "' the method of "inar' (ssion.

) fu' grown paramecium di!ides its "od' into two parts to

form two smaer paramecia.

This happens "' the di!ision of nuceus foowed "' the

di!ision of c'topasm.

Multiple )ission

In mutipe (ssion the parent organisms spits to form man' new organisms at

the same time .the c'st the nuceus of ce spits se!era times to form man'

smaer nucei caed daughter nucei :itte "its of c'topasm coect around each

daughter nucei and thin mem"ranes are formed around them. In this wa' man'

new daughter ces are formed from a singe parent ce within the c'st. In fact

as man' daughter ces are formed as the num"er of daughter nucei produced

"' the di!isions of the parent nuceus. ;hen the fa!oura"e conditions arri!e the

c'st "reaks open and the man' daughter ces present in it are reeased each

forming a new organism. In this wa' a singe ceed parent in it undergoes

mutipe (ssion to reproduce man' daughter ces at the same time.

*#DD'(+In "udding a sma part of the "od' of the parent organism grows out as a "ud

which then detaches and "ecomes a new organism.

An Amoeba

reproduces ,ust by

splitting into two

$eishmania

Reproduction by multiple

-ssion



+'dra is a simpe muticeuar anima. +'dra reproduces "' the process of

"udding.

In +'dra (rst a sma outgrowth caed "ud is formed on the side of its "od' "'

the repeated mitotic di!isions of its ces. This "ud then grows gradua' to form a

sma +'dra "' de!eoping a mouth and tentaces. )nd (na' the tin' new +'dra

detaches itsef from the "od' of parent +'dra and i!es as a separate organism.In this wa' the parent +'dra has produced a new +'dra. <east reproduces "'

"udding.

In 'east (rst a "ud appears on the outside of the ce wa. The nuceus of parent

'east ce then di!ides into two parts and one part of the nuceus mo!es into the

"ud. Utimate' the "ud separates o0 from the parent 'east ce and forms a

new 'east ce. The "udding in 'east howe!er often takes pace so fast that the

(rst "uds start forming their own "uds and a of them remain attached to thechain separate from one another and form indi!idua 'east pants.

%&R! )&RMAT'&(

In spore formation the parent pant produces hundreds of microscopic reproduce

units caed spores. ;hen the spore case of the pant "ursts then the spores

spread into air. ;hen these air="orne spores and on food under fa!oura"e

conditions the' germinate and produce new pants. The common "read moud

formation.



The common "read moud pant consists of (ne thread=ike pro>ection caed

h'phae and thin stems ha!ing kno"=ike structures caed sporangia. Each

?no"=ike structure contains hundreds of minute spores encosed in a spore case.

;hen the spore case "ursts the tin' spores are dispersed in air.

These spores are the asexua reproducti!e units which can produce more "read

moud pants under suita"e conditions.

R!+!(!RAT'&(

The process of getting "ack a fu organism

from its "od' parts is caed regeneration.

Panaria is a -atworm which is found in

freshwater ponds and sow=mo!ing streams.

Panaria possesses great power of

regeneration. If the "od' of panaria somehow

gets cut into a num"er of pieces then each

"od' piece can regenerate into a compete

panaria "' growing a the missing parts.

)RA+M!(TAT'&( The "reaking up of the "od' of a simpe muticeuar organism into two pieces on

This is a common bread mould plant. 'treproduces by forming spores.

*read mould growing

on a slice of bread.This antibiotic drug

called pencillium

This is pencillium

fungus. 't also

reproduces by

forming spores.

*read mould fungus

as seen through a

magnifying glass.

They white threads

are hyphae. !ach

black dot is a

sporangium which

contains thousands

of tiny spores.



maturing each of which su"se@uent' grows to form a compete new organism

is caed fragmentation. The organisms ike &pirog'ra and sea anemones can

reproduce "' the method of fragmentation.

&pirog'ra is a green (amentous aga pant which is found in ponds akes and

sow mo!ing streams spirog'ra (ament simp' "reaks into two or more

fragments on maturation and each fragment then grows into a new spirog'ra.

The main di0erence "etween (ssion and fragmentation is that in (ssion a

uniceuar organisms "reaks up to form two daughter organisms whereas in

fragmentation a muticeuar organisms "reaks up to form two daughter

organisms.

/!+!TATAT'/! %R&%A+AT'&(

In !egetati!e propagation new pants are o"tained from the parts of od pants

$ike stems roots and ea!es% without the hep of an' reproducti!e organs. The

green grass grown in the (eds after rains from the dr' od stems of grass pantspresent in the (eds "' the method of !egetati!e propagation. 4r'oph'um

eapirogyr

The organisms like spirogyra and sea anemones can reproduce by the method of

pirogyra as seen under the

microscope.

pirogyra reproduces by the

method of fragmentation.



pants can "e reproduced "' !egetati!e propagation "' using either a piece of its

stem or its ea!es. 2or exampe if we pant a "roken piece of the stem of a

"r'oph'um pant in the ground we wi get a new "r'oph'um pan growing

from it in a weekAs time. E!en the ea!es of a "r'oph'um pant can produce

new pants. The ea!es of a "r'oph'um pant ha!e specia t'pe of "uds in their

margins. These "uds ma' get detached from the ea!es fa to the ground and

then grow to produce new "'roph'um pants. The "uds can aso drop to the

ground together with the eaf and then grow to produce new pants.

/one' pant can aso "e grown "' !egetati!e propagation "' using a piece of its

stem. ;e wi now descri"e he !egetati!e propagation of pants "' using tu"ers

which are the modi(ed underground stems. ) tu"er is the thickened

underground stem of a pant which is swoen with stored food. Potato tu"er can

"e used for the !egetati!e reproduction of potato pants. ) potato tu"er has

man' "uds on its "od'. These "uds act as organs for !egetati!e reproduction.

;hen a potato tu"er is panted in the soi then the !arious "uds of the potato

tu"er start growing to form new potato pants. It is not necessar' to pant the

whoe potato in the ground to produce new potato pants.

A leaf of *ryophyllum plan with buds

in its margin 0or edges1

A potato plant with tubers./egetative propagation of potato

plant from a potato tuber. A new

potato plant grows from each bud on

the old potato.



The !egetati!e propagation method of producing potato pants "' tu"ers is much

faster than the production of potato pants from seeds.

ART')'C'A$ %R&%A+AT'&( &) %$A(T

The process of growing man' pants from one pant "' man=made methods iscaed arti(cia propagation of pants. The three common methods for the

arti(cia propagation of pants are#

1. Cuttings3. :a'ering5. Brafting.

Cutting

) sma part of a pant which is remo!ed "' making a cut with a sharp knife is

caed a cutting.

In this method a cutting of the parent pant ha!ing some "uds on it is taken and

its ower part is "uried in the moist soi. )fter a few da's the cutting de!eops

roots and shoot and grows into a new pant. Cuttings are a means of asexua

reproduction in pants. The formed from a cutting is exact' simiar to the parent

pant. The pants ike

rose "ougain!iea chr'santhemum grapes sugarcane "ananas and cactusetc. can "e grown "' means of cutting.

$ayering

In this method a "ranch of the pant is pued towards the ground and a part of it

is co!ered with moist soi ea!ing the tip of the "ranch exposed a"o!e the

ground. )fter some time new roots de!eop from the part of the "ranch "uried in

the soi. The "ranch is then cut o0 from the parent pant. The part of the "ranch

which has de!eoped roots grows to "ecome a new pant. asmine pant is

propagated or produced "' the a'ering method.

A new plant is formedtem cutting develops

roots and shoot

A stem cutting 0with

bud1 planted in soil

The propagation of plants by cuttings method



+rafting

Brafting is a method in which the cut stems of two di0erent pants are >oined

together in such a wa' that the two stems >oin and grow as a singe pant.

$i% The cut stem of a pant ha!ing roots is caed stock. &tock is the ower

part of a pant ha!ing the roots.

$ii% The cut stem of a pant ha!ing roots is caed scion. &cion is the upper

part of a pant which of a pant ha!ing the roots.

)ppe peach apricot and pear trees are often grafting.

+rafting was used to grow this

apple tree.



Advantages of Arti-cial /egetative %ropagation

1. The new pants produced "' arti(cia !egetati!e propagation wi "eexact' ike the parent pants. )n' descri"e features of the parent pant

wi "e repicated in the new pants.3. The fruit trees grown from seeds ma' take man' 'ears "efore the' start to

"ear fruit. 4u the fruit trees grown from cutting or "' grafting start to "ear

fruits much earier.5. The pants grown "' !egetati!e propagation usua' need ess attention in

their ear' 'ears than the pants grown from seeds.6. The pants can "e grown from >ust one parent pant "' arti(cia

propagation.7. ;e can aso get seedess pants "' arti(cia propagation.

T'#! C#$T#R! The production of new pants from a sma piece of pant tissue remo!ed from the

growing tips of a pant in a suita"e growth medium is caed tissue cuture.

1. ) sma piece of pant tissue is taken from the growing point of the pant

and paced on a sterie >e' which contains nutrients and pant hormones.

The hormones make the ces in the pant tissue di!ide rapid' producing

man' ces which form a shapeess ump of mass caed caus.

3. The caus is then transferred to another >e' containing suita"e pant

hormones which stimuate the caus to de!eop roots.

5. The caus with de!eoped roots is then put on a 'et another >e'

containing di0erent hormones which stimuate the de!eopment of shoots.

6. The caus ha!ing roots and separates into tin' pantets. In this wa' man'

tin' pantets are produced from >ust a few origina pant ces.

7. The pantets thus produced are transpanted into pots or soi where the'

can grow to form mature pants.

Many plantlets areproduced. These can be

transplanted into pots or

soil

Callus developsroots and

shoots

%lant tissue growsto form callus

A small piece of planttissue being taken

from the growing

point 0tip1 of a plant



The tissue cuture techni@ue is "eing used increasing' for the production of

ornamenta pants ike orchids dahia carnation chr'santhemum etc.

Advantages of Tissue Culture

1. Tissue cuture is a !er' fast techni@ue. Thousands of pantets can "e

produced in a few weeksA time from a sma amount of pant tissue.

3. The new pants produced "' tissue cuture are disease free.

5. Tissue cuture can grow pants round the 'ear irrespecti!e of weather or

season.

6. 9er' itte space is needed for de!eoping new pants "' tissue cuture.

Do &rganisms Create !xact Copies of Themselves in Asexual

Reproduction

)sexua reproduction usua' resut in the production of genetica' identica

o0springs the on' !ariation arises as a resut of occasiona inaccuracies in DN)

repication at the time of ce di!ision. The

materia which carries genetic information from the parents to the o0springs is

DN) Deox'ri"o Nuceic )cid. The "asic of asexua reproduction is mitosis. This

is the di!ision of a nuceus into two identica daughter nucei.

Each daughter nuceus has the same genetic make up "ecause of the repication

of DN) of the parent ce the di!ision of the nuceus the rest of parent ce

di!ides to form two genetica' identica ces. The daughter ces can then formtwo o0springs. 2rom this we concude that a the o0springs produced "' one

The tissue culture techni2ue of producing new

The process of asexual



parent as a resut of asexua reproduction are usua' genetica' identica. ;e

wi now expain how sight !ariations are introduced in asexua reproduction. The

repication of DN) in the ce is done "' certain "iochemica reactions which

s'nthesi,e more of genetic materias. No "iochemica reaction can reproduce

1 per cent same resuts. &o when the DN) aread' present in the nuceus of

the parent ce is repicated "' making more DN) at the time of asexua

reproduction then sight !ariations come in the two copies formed. Due to this

the two DN) moecues formed "' repication wi "e simiar "ut ma' not "e

exact' identica to the origina DN). These sight !ariations in the repication of

DN) moecue wi ead to sight !ariations in the o0springs produced "' asexua

reproduction.

The importance of !ariations in organisms introduced during reproduction is that

it heps the species of !arious organisms to sur!i!e and -ourish e!en in ad!erse

en!ironment.

!"#A$ R!%R&D#CT'&(

&exua reproduction takes pace "' the com"ination of specia reproducti!e ces

caed sex ces. The ces in!o!ed in sexua reproduction are caed gametes. In

sexua reproduction a mae gamete fuses with a femae gamete to form a new

ce caed ,'gote. This ,'gote then grows ad de!eops into a new organism in

due course of time. Bametes are aso sometimes caed germ ces.

!"#A$ R!%R&D#CT'&( '( )$&3!R'(+ %$A(T

The -owering pants reproduce "' sexua reproduction method. The sex organs

of a pant are in its -owers. The function of a -ower is to make mae and femae

gametes and to ensure that fertiisation wi take pace to make new seeds for

the reproduction of pant.

)lowers contain the sexual reproductive organs of

a 4owers make fruits which contain seeds. These

seeds produce new plants.

Apples5 oranges5 lemons and tomatoes5 etc.5 are all

fruits. They contain the seeds of their plants inside

them. These seeds can be sown in the soil to grow

more lants.



The exual Reproduction in %lants

1. The mae organ of -ower caed stamen makes the mae gametes of

the pant. These mae gametes are present in poen grains.

3. The femae organ of a -ower caed carpe makes the gametes of thepant. These femae gametes are present in are aso caed o!a egg

ces or >ust eggs.5. The mae gametes present in poen grains fertiise the femae gametes

or egg ces present in o!ues.

6. The fertiised egg ces grow within o!ues and "ecome seeds.7. The seeds produce new pants on germination $under conditions of

water warmth air and ight etc.%.

The main parts of a -ower are# Receptace sepas petas stamen and carpe.

1. Receptacle. The "ase of a -ower to which a the parts of a -ower are

attached is caed receptace.

3. epals. The green eaf=ike parts in the outermost circe of a -ower are

caed sepas. ) the sepas taken together are caed ca'x. The function

of sepas is to protect the -ower in its initia stages when it is in the form

of a "ud.5. %etals. The coourfu parts of a -ower are caed petas. The petas ie

inside the sepas. ) the petas taken together are caed coroa. Thepetas are usua' scented. The function of petas is to attract insects and

to protect the reproducti!e organs which are at the centre of the -ower.

Diagram to show the parts of a



6. tamen. The itte staks with swoen tops >ust inside the ring of petas in

a -ower are caed stamens. &tamen is he mae reproducti!e organ of the

pant stamen produces poen grains. The stamen is made of two parts# a (ament )nd an anther.

The stak of stamen is caed (ament and the swoen top of stamen is caed

anther. It is actua' the anther of a stamen which makes the poen grains and

stores them. Poen grains contain the mae gametes of the pant.

7. Carpel. In the centre of a -ower there is a -ask=shaped organ caed

carpe. Carpe is the femae reproducti!e organ of the pant. ) carpe is

made of three parts# sigma st'e and o!ar'. The top part of carpe is

caed stigma. &tigma is for recei!ing the poen grains from the anther ofstamen. &tigma is stick' so that is for poen can stick to it. The midde

part of carpe is caed st'e. &t'e is a tu"e which connects stigma to the

o!ar'. The swoen part at the "ottom of a carpe is caed o!ar'. The o!ar'

makes o!ues and stores them. O!ues contain the femae gametes. Each

o!ue contains on' one femae gamete of the pant.

The femae gamete of the pant which is present inside

the o!ue is caed o!um or egg. The femae gametes of a

pant are made in the o!ar' of carpe. The femae

organ of a pant is known "' two names# carpe

and pisti. The -owers which contain on' one sex

organ either stamens or carpes are caed unisexua

-owers. The -owers which contain "oth the sex

organs stamens as we as carpe are caed

"isexua -owers. ) new seed of the pant is formed

when the mae gamete in a poen grain unites with the femae

gamete present in the o!ue. This happens in two steps# poination

and fertiisation.

tamen6 Male reproductive organ

of a plant

This picture shows the carpel of a tulip

4ower surrounded by many brown



%&$$'(AT'&(

The transfer of poen grains from the anther of a stamen to the stigma of a

carpe is caed poination. Poination can occur in two wa's# sef=poination and

cross=poination.

;hen the poen grains from the anther of a -ower are transferred to the stigma

of the same -ower it is caed sef=poination. ;hen the poen grains from the

anther of a -ower on one pant are transferred to the stigma of a -ower on

another simiar pant it is caed cross=poination. ;hen an insect sits on the

-ower of a pant for sucking nectar then the poen grains form the anther of this

-ower stick to its "od'. )nd when this insect now sits on another -ower of

another simiar pant then the poen grains sticking to its "od' are transferred

to the stigma of this second -ower.

In this wa' the insect transfers the poen grains from the anther of -ower in one

pant to the stigma of -ower in another pant and causes cross=poination.

)!RT'$'AT'&(2ertiisation occurs when the mae gamete present in poen grain >oins

with the femae gamete present in o!ue.

elf7pollinationCross7

'nsects which sit on di8erent

4owers to suck nectar help in

pollination by transferring pollen

from the anther of one 4ower tothe stigma of another 4ower.

The male 4owers in this picture are

shedding a dust of their pollens into the

air. These pollens are then carried away

by wing to the stigma of another 4owerfor pollination.



) mae gamete mo!es down the poen tu"e. The poen tu"e enters the o!ue in

the o!ar'. The tip of poen tu"e "ursts open and mae gamete comes out of

poen tu"e. In o!ar' the mae gamete of poen com"ines with the nuceus of

femae gamete or egg present in o!ue to form a fertiised egg. )nd we that

fertiisation has taken pace.

)ormation of )ruits and eeds The fertiised egg di!ides se!era times to form an em"r'o within the

o!ue. The o!ue de!eops a tough coat around it and is gradua' con!erted into

a seed. In fact a the eggs in the "ecome seeds. The o!ar' of -ower de!eops

and "ecomes a fruit. The other parts of -ower ike sepas petas stamens

stigma and st'e dr' up and fa o0. On' the o!ar' is eft "ehind. &o at the pace

on pant where we had a -ower origina' we now ha!e a fruit.

) fruit protects the seeds. &ome fruits are soft sweet and >uic' ike mangoes and

oranges. 4ut some fruits are hard dr' and wood' ike peanuts and amonds etc.

) seed is the reproducti!e unit of a pant.

An apple is a fruit. 't has seeds

of apple tree in it.

A pea pod is a fruit. 't has

seeds of pea plant inside it.



The parent pants reproduce more pants ike itsef "' forming seeds through-owers.

+ermination of seeds ;hen a seed gets water air and warmth etc. it "egins to grow. ;hen a

seed "egins to grow it is said to germinate. The "eginning of the growth of

seeds is caed germination of seeds. Bermination "egins when the seed a"sor"s

water swes and "ursts through the seed coat. The water heps the en,'mes to

function in the seed. The en,'mes digest the stored food in cot'edons and make

it sou"e. This sou"e food makes the radice and pumue present in the seed to

grow. The radice of the seed grows (rst to form the root. The root pushes down

into the soi and "egins to a"sor" water and mineras from the soi. )fter this the

pumue grows upwards to form the shoot. The shoot and root grow further. ;hen

the shoot comes up a"o!e the ground it de!eops green ea!es. The green

ea!es of the shoot "egin to s'nthesis own food in the presence of sunight. This

seeding grows gradua' and utimate' "ecomes a new pant.

A been seed cut

A been seed

3heat *engal gram Corn seeds *ean seeds



!"#A$ R!%R&D#CT'&( '( A('MA$

)n anima ha!ing mae sex ces caed FspermsA in its "od' is caed mae. )n

anima ha!ing femae sex ces caed Fo!aA $or eggs% in its "od' is caed femae.

+ametes

The ces in!o!ed in sexua reproduction are caed gametes. The mae gamete

in animas is caed sperm and the femae gamete in animas is caed o!um or

egg.

2usion of gametes gi!es rise to a singe ce caed ,'gote. The ce which is

formed "' the fusion of a gamete and a femae gamete is caed ,'gote.

)ertilisation The fusion of a mae gamete with a femae gamete to form a ,'gote during the

sexua reproduction is caed fertiisation. The fusion of a sperm with an o!um to

eeds germinate under suitable conditions to produce new plants.

These pictures show the germination of a bean seed to form a bean

lant.

A human ovum or egg 0female gamete1. An

ovum or egg is round and about 9.:; mm in

diameter. The ovum or egg is also single cell

having a nucleus5 cytoplasm and cell

membrane. This -gure is a highly enlarged

sketch of an ovum or egg.

A human sperms 0male gamete1. A sperm is about 9.9;

mm long. A sperm has a head5 a middle piece and a tail.

A sperm is a single cell with nucleus5 cytoplasm and cell

membrane. This -gure is a highly enlarged sketch of a

sperm.



form a ,'gote during sexua reproduction is caed fertiisation. The un"orn "a"'

in the uterus in the ater stages of de!eopment is caed a foetus.

'nternal and !xternal )ertilisation The fertiisation which occurs inside the femae "od' is caed

interna fertiisation. Interna fertiisation takes pace in mammas "irds and

repties. The fertiisation which occurs outside the femae "od' is caed externa

fertiisation. In amphi"ians and (shes externa fertiisation takes pace.

In externa fertiisation the mae and femae animas reease their sperms and

eggs in water where fertiisation takes pace "' coisions "etween sperms and

eggs. 2or exampe the maes and femaes of frogs and (shes reease their

sperms and eggs in water in which the' i!e. The sperms then coide with the

eggs and fertiise them outside the "od' of femae frog or (sh. There are two

di0erent modes of fertiisation in nature# interna fertiisation and externa

fertiisation. The method in which a ,'gote grows and de!eops into a fu

organism aso !aries in di0erent animas. 2or exampe in human "eings the

This is foetus formed from

a <ygote 0or fertilised

egg1. 't will grow further

and become a baby.

This is a <ygote 0or

fertilised egg1

formed by the

fusion of a spermwith an ovum or

egg.

This picture shows

an ovum or egg

0greatly magni-ed1.

This picture shows a number

of sperms 0greatly

magni-ed1.

As the female frog lays eggs in water5 the male frog

releases its sperms. The collisions between sperms and

eggs lead to fertilisation. This is an example of external

fertilisation.



,'gote grows and de!eops into a "a"' inside the femae "od'. )nd then the

mother gi!es "irth to the "a"'. ust ike humans the animas ike cats and dogs

aso gi!e "irth to their 'oung ones. 4ut the process is entire' di0erent in the

animas which a' eggs. 2or exampe a hen sits on its fertiised eggs for a

considera"e time to gi!e them warmth. During this period the ,'gote grows and

de!eops to form a compete chick. This chick then comes out of egg "' "reaking

its she.

3hy the Amount of D(A not get Doubled during exual Reproduction

The gametes are specia t'pe of ces caed reproducti!e ces which contain on'

haf the amount of DN) as compared to the norma "od' ces of an organism.

How exual Reproduction in Animals Takes %lace&exua reproduction is the most common method of reproduction

in animas. The sexua reproduction in animas takes pace in the foowing steps#

1. The mae parent produces mae gametes caed sperms. The sperm is a

sma ce with a ong tai for mo!ement.

3. The femae parent produces femae gametes caed o!a. The o!um is a

much "igger ce than sperm ha!ing a ot of c'topasm.

5. The sperm enters into the o!um and fuses with it to form a new ce caed

,'gote. This process is caed fertiisation. &o the ,'gote is a fertiised

o!um.6. The ,'gote di!ides and again to form a arge num"er of ces. )nd

utimate' ,'gote grows and de!eops to "ecome a new "a"'.

The whoe process of sexua reproduction in animas in!o!es the

formation of sperms and eggs* >oining together of sperm and egg to form a

,'gote* and then the growth and de!eopment of ,'gote o form a "a"'

anima.

%uberty

)ertilisation of an ovum 0or egg1

by a sperm to form a <ygote.



The age at which the sex hormones "egin to "e produced and the "o' and gir

"ecome sexua' mature $a"e to reproduce is caed pu"ert'%.

On attaining pu"ert' the mae gonads caed testes start producing mae

gametes caed sperms and the femae gonads caed o!aries start producing

femae gametes caed o!a. In addition to producing sex ces mae and femaegonads aso produce and secrete sex hormones with the onset of pu"ert'. The

testes produce the mae sex hormone caed testosterone and the o!aries

produce two femae sex hormones oestrogen and progesterone.

Human Reproductive ystem

The reproducti!e s'stems in human "eings "ecomes functiona at a de(nite age

caed pu"ert'.

TH! MA$! R!%R&D#CT'/! =T!M

The human mae reproducti!e

s'stem consists of the foowing

organs# Testes scrotum

Epidid'mis 9as deferens

semina !esices prostate gand

and penis.

Testes are the o!a shaped

organs which ie outside the

a"domina ca!it' of a man. )

man has two testes. Testes are

the primar' reproducti!e organs

in man. The function of testes is to make the mae sex hormone caed

testosterone. The testes of a man make the sex gametes from pu"ert' onwards

throughout his ife. The testes of a man ie in sma muscuar pouch caed

scrotum outside the a"domina ca!it'. The testes are outside the a"domina

ca!it' of the "od' "ecause the sperm formation re@uires a ower temperature

than the norma "od' temperature. 4eing outside the a"domina ca!it' the

temperature of scrotum is a"out 5oC ower than the temperature inside the "od'.

In this wa' the testes pro!ide an optima temperature for the formation of

sperms. The sperms

formed in testes come out and go into a caed epidid'mis. The sperms get

stored temporari' in epidid'mis. 2rom epidid'mis the sperms are carried "' a

ong tu"e caed !as deference which >oins with another tu"e caed urethra

coming from the "adder. )ong the path of !as deferens the gands caed

semina !esices and prostrate gand add their secretions to sperms so that the

sperms are now in a i@uid. This i@uid pus the sperms it contains is caed

semen. The secretions of semina !esices and prostrate gand pro!ide nutrition

to the sperms and aso make their further transport easier. Urethra forms a

common passage for sperms and urine. Urethra carries the sperms to an organcaed penis which opens outside the "od'. The penis passes the sperms from the



manAs "od' into !agina in the womanAs "od' during mating for the purpose of

reproduction.

The female reproductive system

The human femae reproducti!e s'stem consists of the foowing organs#

O!iducts Uterus and 9agina.

O!aries are the o!a shaped organs which are inside the a"domina ca!it' of a

woman near the kidne's. ) woman has two o!aries. O!aries are the primar'

reproducti!e organs in a woman. The function of o!aries is to make mature

femae sex ces caed o!a or eggs hormones. Each o!ar' is composed of se!era

thousand foices. )t pu"ert' these foices mature to form the ripe eggs or ripe

o!a.

ust a"o!e the o!aries are the tu"es caed o!iducts. The o!iducts are not

direct' connected to o!aries "ut ha!e funneed shaped openings which amost

co!er the o!aries. The o!um reeased "' an o!ar' goes into the o!iduct through

its funne=shaped opening the fertiisation of egg "' a sperm takes pace in the

o!iduct.

The two o!iducts connect to a "ag ike organ caed uterus at their other ends.

The growth and de!eopment of a fertiised o!um into a "a"' takes pace in the

uterus. The uterus is connected through a narrow opening caed cer!ix to

another tu"e caed !agina which opens to the outside of the "od'. 9agina

recei!es the penis for putting sperms into the womanAs "od'. 9agina is a tu"uar

structure. 9agina is aso caed "irth cana "ecause it is through the passage thatthe "a"' is "orn after the competion of de!eopment inside the uterus of the

The female reproductive system inhumans 0front view1



mother. Pease note that in woman the opening for passing out urine and the

!agina opening are separate.

)ertilisation The sperms made in the testes of man are introduced into the !agina of the

woman through penis during copuation. In this wa' miions of sperms arereeased into the !agina at one time. The sperms are high' acti!e and mo"ie.

The sperms mo!e up through cer!ix into the uterus. 2rom uterus the sperms

pass into the o!iducts.

The sperm fuses with the o!um in the o!iduct to form a ,'gote. The fertiisation

of the o!um takes pace in the o!iduct.

Development of !mbryo

;hen the o!um is fertiised in the o!iduct then a ,'gote is formed. The ,'gote

di!ides rapid' "' mitosis as it mo!es down sow' in the o!iduct and forms a

hoow "a of hundreds of ces. This hoow "a of ces now caed an em"r'o

sinks into the soft and thick ining of the uterus and gets em"edded in it. The

em"edding of em"r'o in the thick ining of the uterus is caed impantation. )fter

impantation a disc=ike specia tissue de!eops "etween the uterus wa and the

em"r'o which is caed pacenta. The exchange of nutrients ox'gen and waste

products "etween the em"r'o and the mother takes pace through the pacenta.

The time period

from the fertiisation up to the "irth of the "a"' is caed gestation.

Di8erences between >ygote . !mbryo and )oetus ????

)oetus

1. ) foetus is formed "'

the growth and

de!eopment of an

em"r'o.

3. ) foetus is an un"orn

"a"' in the uterus in the

ater stages of

de!eopment.

5. ) foetus is aso

!mbryo

1. )n em"r'o is formed "'

the repeated ce di!ision

of ,'gote.

3. )n em"r'o is an un"orn

"a"' in the uterus in the

ear' stage of

de!eopment.

5 an em"r'o is

muticeuar. The "od'

>ygote

1. ) ,'gote is formed "'

the fusion of mae and

femae gametes.

3. ) ,'gote is the

"eginning of the

formation of the "a"'.

5 ) ,'gote is a singe ce.

It is smaer than a fu

stop.



exual cycle in )emales6 Menstruation

The reease of an o!um from an o!ar' is caed o!uation. In human femaes the

o!aries start reeasing o!um or egg. Once e!er' 3G da's from the age of pu"ert'.

4efore e!er' o!uation the inner ining of the uterus "ecomes thick and soft with

ot of "ood capiaries in it. These changes in the uterus are necessar' "ecause

in case the o!um reeased "' the o!ar' gets fertiised "' the sperm then the

uterus has to keep the fertiised o!um for further de!eopment and supp' it with

food and ox'gen etc. so that it man' grow into a "a"' in due course of time. If

howe!er a sperm is not a!aia"e at the time of o!uation then fertiisation ofo!um does not take pace since the o!um is not fertiised so the thick and soft

uterus ining ha!ing ot of "ood capiaries in it is not re@uired. Thus the

unfertiised o!um dies within a da' and the uterus ining aso "reaks down. &ince

the thick and soft uterus ining contains a ot of "ood !esses so the "reaking of

the uterus ining produces "ood aong with other tissues. This "ood and other

tissues come out of the !agina in the form of "eeding. &o the "reaking and

remo!a of the inner thick and soft ining of the uterus aong with its "ood

!esses in the form of !agina "eeding is caed menstrua -ow of menstruation.

/enstruation occurs e!er' 3G

da's "ecause o!uation occurs e!er' 3G da's. The menstrua c'ce is controed"' hormones.

!mbryo )oetus>ygote

These pictures show the di8erence between a human <ygote5 an

Thick $ining of

A thick lining grows in the uterus to

receive the fertilised egg cell 0if any1.



/enstruation stops temporari' when the o!um gets fertiised and the woman

gets pregnant. /enstruation restarts after the "irth of the "a"'.

The (rst occurrence of menstruation at pu"ert' is caed menarche. The

permanent stoppage of menstruation in a woman is caed menopause.

*'RTH C&(TR&$ M!TH&D

The pre!ention of pregnanc' in women is caed contraception.

1. 4arrier methods3. Chemica methods and5. &urgica methods.

*arrier Methods

In the methods of pre!enting pregnanc' the ph'sica de!ices such as

condoms and diaphragm are used. Condoms are used "' maes $"'putting them as a co!ering on the penis%. Diaphragm is used "' femaes

$"' putting it in the !agina to co!er the cer!ix%. Condom as we as

diaphragm pre!ent the sperms form meeting he o!um "' acting as a

"arrier "etween them. )n important "ene(t in the use of condom is that it

protects a person from the sexua' transmitted diseases such as

gonorrhoea s'phiis and )ID&.

Chemical Methods

In the chemica methods of pre!enting

pregnanc' the femaes use two t'pes of pis#ora pis and !agina pis which are made of

speci(c drugs. The ora pis contain hormones

which stop the o!aries from reeasing o!um

into the o!iduct.

Ora pis are aso caed ora contracepti!es.

This is a !er' e0ecti!e method of pre!enting

pregnanc' so ong as the pis are taken at

the right time. The !agina pis contain the

chemicas caed spermicides which ki thesperms.

'ntra7#terine Contraceptive Device 0'C#D1

The use of intrauterine contracepti!e de!ice caed Copper=T is aso !er' e0ecti!e

in pre!enting pregnanc'. ) Copper=T is pace inside the uterus "' a doctor or a

trained nurse. The IUCD or Copper=T pre!ents the impantation of fertiised egg in

the uterus. If a woman uses a Copper=T as a method of contraception for a!oiding

unwanted pregnancies then Copper= T cannot protect her from ac@uiring

sexua' transmitted diseases.

urgical Methods

ome women choose oral pills as

contraceptive for birth control.



&urgica methods of "irth contro are a!aia"e for maes as we as femaes. In

maes a sma portion of the sperm duct is remo!ed "' surgica operation and

"oth the cut ends are igated proper'. This pre!ents the sperms from coming

out. The surgica procedure carried out in maes is caed !asectom' in femaes

a sma portion of the o!iducts is remo!ed "' surgica operation and the cut ends

are igated. This pre!ents the o!um from entering into the o!iducts. The surgica

procedure carried out in femaes is caed tu"ectom'.

exual Transmitted Diseases 0TD1

The diseases which are spread "' sexua contact with an infected person are

caed sexua' transmitted diseases. &ome of the common sexua' transmitted

diseases are#

$i% Bonorrhoea

$ii% &'phiis and$iii% )ID& $)c@uired Immune De(cienc' &'ndrome%.

Bonorrhoea and s'phiis are caused "' "acteria. The "acteria which

cause these diseases spread through sexua contact with an infected

person.

The most common s'mptoms of the these sexua' transmitted diseases are

"urning sensation at urination passing of urethra discharge and sores in the

genitas. Bonorrhoea and s'phiis are cura"e diseases. )ID& disease is caused

"' a !irus caed +I9 $+uman Immunode(cienc' 9irus%. )ID& damages the "od'As

immune s'stem so that the "od' "ecomes weak and cannot protect itsef against

infection. &o )ID& is a !er' dangerous disease which eads to death. No de(nitecure has "een found for the )ID& disease so far.

This is Human 'mmunode-ciency /irus 0H'/1. The

white bood cells 03*Cs1 of a person destroy

disease7causing bacteria and protect the health of a

person. H'/ infects white blood cells and destroysthem gradually. This reduces the immunity 0or

resistance1 of the body to -ght diseases. Due to

this5 diseases which are normally 2uite mild can kill

a person with H'/ who develops A'D disease.

This person is su8ering from A'D disease caused by

H'/. The immune system of this person has been

damaged making his body so weak that it cannot

protect itself against even common infections. Thisperson is ,ust waiting to die.

reproduction - class 10th

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