2. The production of new organism from existing
organism of same species is called reproduction.
It is essential for the survival of species on the
earth or to ensure continuity of life on earth.
For Example : Reproduction by human being
ensures that human species will continue to
exist on this earth for all time. It give rise to
more organisms with same basic characteristics
as their parents.
3. Existing organism are called parents.
New organism are called offsprings.
The chromosomes in the nucleus of a cell
contain information for inheritance of features
from parents to next generation in the form of
DNA molecules.
4. Significance of Reproduction
• 1. It ensures continuity of life.
• 2. It increases population of life.
• 3. It provides variations which are favourable from
one generation to another.
5. Types of Reproduction
(1) Asexual
(2) Sexual
Asexual Reproduction
The production of new organism from a single parent without the involvement of sex
cell.
In asexual reproduction, part of the parents organism separates off and grows into a
new organism.
Only one parent is needed to produce new organism.
There are 6 different methods:
(1) Fission(amoeba)
(2) Budding(hydra)
(3) Spore formation(Rhizopus fungus)
(4) Regeneration(flatworm)
(5) Fragmentation(spirogyra)
(6) Vegetative propagation (flowering plant-rose)
6. Sexual Reproduction
The sex cell of one parent fuses with sex cell of other parent
to form a new cell called zygote. The zygote develops to form
new organism.
Sex cell or gametes are of 2 types:
(1) Male-Sperm
(2) Female-Ovum
8. Fission
•Fission is an asexual reproduction that is common in most unicellular
organisms.
•When the fission results in two daughter cells, it is binary fission (e.g.
paramecium).
•When fission results in many daughter cells, it is called multiple fission (e.g.
Plasmodium).
•Planes of fission may be different for different organisms.
10. Multiple Fission
In the multiple fission, the nucleus of the parent cell divides multiple times by
amitosis (direct cell division), producing several nuclei. The cytoplasm, later
on, separates, creating multiple daughter cells. Multiple fission occurs during
unfavorable conditions.
14. In Budding Small part of the body of parent organism
grows out as a bud which then detaches and become a
new organism.
For Example : Hydra, Yeast
These organism use regenerating cells. First a small outgrowth
called bud is formed on the side of its body by division of its
cells. This bud then grows gradually to form a small hydra.
Finally the tiny new hydra detaches itself from the body of
parent hydra and lives as a separate organism.
16. The parent plant produces hundreds of reproductive units
called spores. When the spore case of plant burst then the spores
spread into air. Under favourable conditions they germinate and
produce new plant.
For Example : Rhizopus, mucor(fungi), ferns, mosses (bread mould)
It consist of
(1) Fine, thread like projections called hypae
(2) Thin stem
(3) Knob like structures called sporangia (contain hundred of minute
spores)
17. These spores are sexual reproductive units.
This method is used by unicellular as well multicellular
organism.
19. The process of getting back a full organism from its body part is called
regeneration.
For Example : Hydra, planaria (flatworm)
Regeneration is carried out by specialised cells.
These cells increase in number very quickly and make large number of
cells. From this mass of cell, different cells undergo changes to become
various cell types and tissue. These changes take place in an organised
sequence called as development. These tissue form various organs and
body parts. This mode can be used to produce only those organism which
have relatively simple body organisation consisting of only few
specialised cells or tissue.
21. The breaking up of a body of a simple multicellular organism into two
or more pieces on maturing, each of which grows to form a complete
new organism is called fragmentation.
For Example: Spirogyra (a green filamentous algae plant found in
ponds, lakes etc.), sea anemones (marine animal)
The filament simply breaks into two or more fragments on maturation
and each fragment grows into new spirogyra.
All multicellular organism can not reproduce by this method because
random increase in number of cells, organisation into tissue and then
organs is not practical.
22. Vegetative Propagation
New plants are obtained from the parts of old plants without the help of
any reproductive organ.
It involves the growth and development of one or more bud present on
the old part of a plant to form a new plant. These buds are in the
inactive state in old parts of the plant. When provided with suitable
conditions these buds grow to form new plant.
For Example : Sugarcane, roses, grapes, orange, jasmine etc.
23. Advantages of vegetative Propagation
(1)The new plant produced will be exactly like parent plant.
(2) The fruit trees grown by grafting grown by grafting or cutting
start to bear fruit much earlier.
(3) The plants usually need less attention in their early years than
plants grown from seeds.
(4) Many plants can be grown from just one parent plant.
25. Cutting
A small part of a plant which is removed by making a cut with
a sharp knife is called cutting. A cutting of parent plant
having some bud on it is taken and its lower part is buried in
moist soil.
For Example : Grapes, sugarcane, bananas, cactus,
bougainvillea.
26. Layering
A branch of plant is pulled towards the ground and a part of it is covered
with moist soil leaving the tip of branch exposed above the ground. After
some time new root develops from the part of branch buried in the soil.
The branch is then cut off from parent plant.
For Example : Jasmine, lemon, guava, strawberry.
27. Grafting
In this the cut stem of two different plants(One with root and other
without root)are joined together in such a way that the two stems join and
grow as a single plant.
For Example : Apple, apricot, peach, pear.
28. The significance of vegetative propagation:
1.The plants produced from vegetative propagation grows
quicker than the plant grown from seeds and are relatively
cheaper.
2.The process helps to improve the quality of plants.
3.The desired characteristics such as color, size, and aroma
of flowers and fruits can be produced by vegetative
propagation.
4.The fruit-bearing plants produce fruit faster than plants
grown from seeds.
29. The disadvantages of Vegetative propagation are:
1.There is overcrowding as no dispersal occurs.
2.Since the daughter plants are identical to the parent plant, there is no
variation.
3.The disease of the parent plant can get transferred to the daughter
plants.
31. The plants in which the sex organs are carried within the flower and
seeds are enclosed in a fruit called angiosperms.
The sex organs of plants are in its flowers. Majority of plants are
bisexual having male and female reproductive organ in same plant.
The male organ of flower called Stamen makes male gametes(pollen
grains)
The female organ of flower called carpel makes female gamete. These
gametes are present in ovules are called ova or egg.
The male gamete present in pollen grains fertilise with female gametes
present in ovules. The fertilised egg grow within ovules and become
seeds. The seed produce new plants on germination.
33. The main parts of plant are Receptacle, Sepals, Petals, Stamen, Carpel.
The base of flower to which all the parts of a flower are attached is
called receptacle. The green leaf like part in the outer circle of flower are
called sepals. The function of sepals is to protect the flower in its initial stage when
it is in the form of a bud.
The colourful parts of a flower are called petals.
All the petals taken together are called corolla. The petals are usually scented.
The little stalks with swollen tops just inside the ring of petals in a flower are
called Stamens.
Stamen has 2 parts
1) Filament(Stalk)
2) Anther(Swollen top)
34. Carpel has 3 parts
(1)Stigma (Top part, receive pollen grains from anther, sticky)
(2) Style (Middle part, it is tube which connect stigma to ovary)
(3) Ovary (Swollen part at the bottom, it makes ovules and store them, contain female
gametes)
The flower which contain only one sex organ either stamen or carpel are called unisexual
flower.
For Example : Papaya, Watermelon.
35. The flower which has both sex organs are called bisexual flowers.
For Example : Rose, mustard
Pollination
The transfer of pollen grains from anther of stamen to stigma of
carpel is called pollination.
It is done by insects, birds, wind, water
When pollen grains from anther of a flower are transferred to stigma
of same flower or another flower on same plant is called self-
pollination.
When pollen grains from anther of a flower on one plant are
transferred to stigma of flower on another similar plant is
called cross-pollination.
36. Fertilisation
It occur when male gamete present in pollen grain joins the female
gamete or egg present in ovule.
(1)When pollen grains fall on the stigma of carpel, it burst open and
grows a pollen tube downwards through the style towards female
gamete in ovary.
(2) A male gamete moves down the pollen tube. The pollen tube
enters the ovule in ovary. The tip of pollen tube bursts open and male
gamete comes out of pollen tube. In ovary, male gamete of pollen
combine with nucleus of female gamete or egg present in ovule to
form a fertilised egg(Zygote).
37. Formation of Fruit and Seeds
(1)The zygote divide several times to form an embryo within the ovule.
(2) The ovule develops a tough coat around it and gradually converted into a seed.
(3) The ovary grows rapidly and ripens to form a fruit (with seed inside it)
(4) The other part of flower like sepals, petals, stamen, stigma, style dry up and fall
off.
(5) The place on plant where we had flower, we now have a fruit. A fruit protect the
seed.
(6) The seed contain a baby plant.
(7) The part of baby in seed which develops into shoot is called plumule and part
which develops into root is called radicle.
The part of seed which contain stored food for baby plant is called cotyledon.
38. Reproduction in human beings
The male gamete or sex cell is called sperm (it has long tail,
motile and can move independently).
The female gamete or sex cell is called ovum or egg (It
contains water, stored food and nucleus).
Fusion of egg and sperm give rise to a single cell
called ZYGOTE.
The fusion of male gamete with female gamete to form a
zygote during sexual reproduction is called fertilisation.
39. The zygote grows and develops to form a new baby .The
stage of development between zygote and newly formed baby
is called embryo.
The fertilisation which occur inside the female body is
called internal fertilisation.
During internal fertilisation, male put his sperm inside a
women body through an organ called penis. These sperms
then fertilise the egg inside the woman’s body.
41. The fertilisation which occur outside the female body
is called external fertilisation.
For Example : Frogs, Toads, Fishes.
The male and female animal releases their sperm
and egg in water where fertilisation take place by
collision between them
43. Fertilisation
(1)Sperms made in testes are introduced into vagina of woman through penis during
mating. Million of sperms are released into the vagina at one time. The sperms
are highly active and mobile. The sperm move up through cervix into uterus.
From uterus, sperms pass into oviduct.
(2) One of the oviduct contain egg released by the ovary during ovulation. Only one
sperm fuses with the egg in oviduct to form Zygote. The fertilisation of egg take
place in oviduct.
(3) The zygote divides rapidly by mitosis as it moves down slowly in oviduct and
form a hollow ball of hundred of cells(embryo).The embryo sinks into soft and thick
lining of uterus and get embedded in it. The embedding of embryo in the thick lining
of uterus is called implantation.
44. (4) After implantation a disc like special tissue develops between
uterus wall and embryo or foetus called placenta. The foetus is
connected to placenta in mother body through umbilical cord.
The exchange of nutrients, oxygen, waste products between embryo
and mother take place through the placenta. The time period from
fertilisation up to birth of baby is called gestation(9 months)
The baby is born as a result of rhythmic contraction of muscles in
uterus.
46. It consist of Testis, scrotum, epididymis, vas deferens or sperm duct,
seminal vesicles, prostrate gland, penis.
(1) Testes
They are oval shaped organs, lie in abdominal cavity. There are 2
testes in male, make male sex cell called sperm and male sex
hormone called testosterone.
(2) Scrotum
Testes lie in small muscular pouch outside the abdominal cavity
because sperm formation requires a lower temperature than
temperature inside body.
(3) Epididymis
The sperms formed in testes come out and go into a coiled tube called
epididymis.
47. (4) Vas Deferens
From epididymis sperms are carried by a long tube which join another
tube called urethra coming from bladder.
(6) Penis
It passes the sperm from man’s body into vagina of female’s body during
mating.
(5) Seminal Vesicles
The glands seminal vesicles and prostrate gland add their secretion
to sperms so that sperms become liquid. Semen contain liquid and
sperm.
48. Male Accessory Reproductive Organs
•Several accessory reproductive organs aid in the reproductive
process.
•The prostate gland and the seminal vesicles are glands of the
reproductive system which make semen and nourish the
sperm.
•Penis, having the urethra passing through it, is called a
copulatory organ.
49. Male Ducts
•In males, the vas deferens and the urethra are the
main ducts.
•A single vas deferens carries sperm from the respective
testis up to the urethra.
•The urethra acts as a common passage for semen and
urine.
51. It consist of Ovaries, oviduct, fallopian tubes, uterus, vagina.
(1) Ovaries
They are oval shaped organ, inside abdominal cavity. There are 2 ovaries, makes egg
or ova and sex hormones, composed of thousand of follicles. At puberty these
follicles mature to form ripe egg.
(2) Oviducts
Above the ovaries, not connected directly to ovaries but have funnel shaped opening
which almost cover ovaries.
The egg released by an ovary goes into oviduct through funnel shaped opening.
Fertilisation take place in oviduct.
52. (3) Uterus
The two oviducts connect to a bag like organ called uterus. The growth
and development of fertilised egg take place in uterus.
(4) Cervix
Uterus is connected through a narrow opening called cervix to another
tube called vagina.
53. Female Accessory Reproductive Organ
•The uterus, oviducts, and vagina are the accessory reproductive
organs in human females.
•The uterus is the site of fetal development, and the vagina
receives sperm from the male. Ovum is carried from the ovaries
to the uterus through a pair of oviducts.
•Mammary glands
•In women there is a pair of well developed mammary gland or
breasts.
54. Puberty
The age at which sex hormones(or gametes) begin to be
produced and boy and girl become sexually mature is
called puberty.
Boys = 13 – 14 years
Girls = 10 – 12 years
55. Adolescence
The time between childhood and adulthood is
called adolescence.
Oestrogen
Male gonads called testes produce male gamete called
sperm. Testes produce sex hormone called testosterone.
Female gonads called ovary produce eggs. Ovaries produce
sex hormones called oestrogen, progesterone.
56. Common changes in Boys and Girls at Puberty
(1)Hair grow under armpits, in genital area between the thighs.
(2) Thinner hair appear on arms and legs.
(3) Skin become oily and develops pimples.
Changes in Girls at Puberty
(2)Breasts develop and enlarge.
(2) Hips broadens
(3) Extra fat is deposited in various parts of body like hip and thigh.
(4) Fallopian tubes, vagina, uterus enlarges.
57. Changes in Boys at Puberty
(1)Hairs grow on chest, face (beard, moustache)
(2) Body become muscular.
(3) Voice deepens
(4) Chest and shoulder broaden.
(5) Penis and testis become large.
(6) Testes produce sperm.
(7) Feeling and sexual drives.
58. Birth Control Method
The diseases which are spread by sexual contact with an infected
person are called sexually transmitted diseases(STD)
For Example: Gonorrhoea, Syphilis (caused by bacteria)
AIDS (Acquired Immuno Deficiency Syndrome)
The Prevention of pregnancy in woman is called contraception.
59. Contraceptive
Any devices or chemical which prevent pregnancy in woman is
called Contraceptive.
(1) Barrier Method
The physical devices such as condom(male)and diaphragm(female-covering on
vagina)are used. They prevent the meeting of sperm and egg.
(2) Chemical Method
The female uses 2 types of pills-oral and vagina. Oral pills are made of specific
hormones which prevent release of egg into oviduct. Vaginal pills contain chemical
which kill the sperm.
(3) Intra-uterine contraceptive device(IUCD)or copper-T
The use of IUCD is placed inside the uterus. It prevents the implantation of
fertilised egg in uterus.
60. (4) Surgical Method
In male a small portion of sperm duct is removed by operation and
both the cut ends are tied property. This prevents sperm from coming
out (VESECTOMY). In female a small portion of oviduct is removed. It
prevent the egg from entering into oviducts(TUBECTOMY).
Abortion /MTP (Medical termination of pregnancy)
Abortion is a medical procedure used to terminate a pregnancy.
It is sometimes referred to as a termination of pregnancy.
Abortion can be done by using medicine or surgery, in which an
embryo or fetus, along with the placenta, is removed from the
uterus.It can be either spontaneous or induced. Spontaneous
abortion is also referred to as a 'miscarriage' that occurs without
any intention. Induced abortion is a technique that is used to
purposefully end a pregnancy.
62. Menstrual Cycle
•Menstruation is the cyclic event of the release of the ovum
from the ovary and its removal from the body when fertilization
does not happen.
•During menstruation, the blood-rich endometrium of the uterus
also breaks down while the ovum is removed from the body.
•Two pituitary hormones, LH and FSH, and two ovarian hormones,
estrogen and progesterone, all have their roles in menstruation.
•In humans, the cycle repeats every 28 days.
63. Menarche
The appearance of first menstruation cycle is called
menarche.
Menopause
The stoppage of menstruation cycle at the age of
45-50 years is called menopause.
Ovulation
Release of egg from ovary at the 14th
day of
menstruation cycle is called ovulation.
