Fill in the blanks.
•The two main methods of reproduction are _____________ and
________________. (sexual reproduction, asexual reproduction)
•The functional unit in a plant’s sexual reproduction is ____________.
•The male reproductive part of a flower is _____________(stamen)
•When the transfer of pollen from an anther to the stigma occurs in the
same flower, the process is called ____________. (self pollination
•________ give rise to variety and diversity. (variation)
•Hydra uses regenerative cells for reproduction in the process of
•Yeast reproduces by _____________. (budding)
•During unfavorable conditions ___________ type of fission is seen in
•A basic process in reproduction is the creation of a _____________ copy.
•_______________ is necessary to maintain the number of individuals of a
Explain the following terms.
•Reproduction: - The fundamental characteristic
of living things to produce new individuals of the
same species, that is a new generation of the
species from and existing individual is known as
•Vegetative propagation: -When new plants are
produced from the vegetative parts like roots,
stems, leaves and buds it is known as vegetative
•Pollination:- The process of transfer of pollen
grains from anther to stigma is called as
Write the functions of the following organs in reproduction.
•It provides the route for the menstrual blood to leave the body during
•It is a pathway through which sperms enters into woman’s body.
•It is a pathway through which a baby comes out of the woman’s body
during child birth.
•It receives pollen grains and on which pollen germinates.
•Ovaries develop and release eggs into the oviduct.
•It secretes hormone estrogen.
•Seminal vesicle and Prostate glands
•Produce ejaculatory fluid which helps the sperm in transport and
•It accommodates a growing foetus.
•It push the baby during labour.
•Longitudinal section of flower.(page number 153 text book)
Binary fission in amoeba. (page number 148 text
•Spore formation in Mucor. (page number 151 text book)
•Human female reproductive system. (page number 157 text book)
What are the advantages of sexual
reproduction over asexual reproduction?
•The offsprings produced by sexual
reproduction are different from parents.
•Variations give rise to variety and
•Variation enables organisms to adapt and
survive in the changing environment.
•It helps to prevent the complete
extinction of animal and plant species.
•Why does menstruation occur?
•A woman’s ovaries usually release
one egg each month.
•When the egg is not fertilized,
menstruation occurs to leave out
the unfertilized egg along with
blood and mucous from the uterus.
•It last for three to five days.
•Describe sexual reproduction in plants.
•In plants, flower is the functional unit concerned with sexual
•In a flower, the ovary produced female germ cell or egg and
the pollen grains produces male germ cells.
•When the pollen lands on stigma, it germinates producing a
pollen tube which grow downwards to reach ovary.
•Each pollen tube contains two male gametes and are
released near the egg,
•One male gamete fuse with the egg cell to form zygote.
•The second male gamete fuse with the secondary nucleus in
the embryo sac to form endosperm. This is called as double
•The zygote develops into embryo and the endosperm serves
as nutritive tissue for the growing embryo.
•Describe the modes of
reproduction in unicellular
Ans. Binary fission, multiple
fission and budding are the
modes of sexual reproduction
in unicellular organisms.
•Binary fission: a.It is employed by most prokaryotes,
some protozoa and some organelles
within eukaryotic cells.
b.In it, the living cell divides into two
equal parts which have the potential
to grow to the size of the original one.
•Multiple fission: a.During unfavourable condition, the
amoeba withdraws its pseudopodia and
form a cyst.
b.Inside the cyst, nucleus divides into many
nuclei and as a result many daughter cells
c.The cyst bursts to release the daughter
cells during favourable condition.
Budding: - Yeast reproduces by budding in which
a small outgrowth is formed on the parental cell.
a.The nucleus of the parental cell divides and
one daughter nucleus migrates into the bud. The
bud increases in size separates and grows
•Explain disadvantages of large family size.
•There is a strong relation between high national fertility rate
and measures of poverty.
•As the population density increases, decrease in per capital
income and natural resources takes place.
•General health goes down and creates an economical
burden on the nation.
•Large families affect both the individual as well as the
•Economic pressure, mother’s poor health, children
neglected at home, poor nourishing, malnutrition, insufficient
medical care, lack of better education, etc., are some of the
disadvantages of large family size.
•Pollination: •The process of transfer of pollen grains from
anther to stigma is called as pollination.
•If this transfer of pollen occurs in the same
flower or another flower of the same plant, it is
known as self pollination.
•On the other hand, if pollen is transferred from
one flower to the flower of another plant, it is
known as cross pollination.
The agents of cross pollination are wind,
water or animals.
The capacity to regenerate is very high among
•They can reconstruct the entire body from the isolated body cells.
•Regeneration is carried out by specialized cells.
•These cells proliferate and make large number of cells which later
developed into various cell types and tissues, and helps in production of
•Eg. When Planaria is cut into many pieces, each piece develops into a
whole Planaria. This process occurs only if the Planaria body gets cut up
into pieces. But animals cannot wait to be cut to reproduce. So
regeneration is not the same as reproduction.
•Germination of seeds : •After fertilization, the zygote divides
several times to form an embryo within
•The ovule develops into a seed and
ovary develops into the fruit.
•The seed contains the future plant. It
develops into the seedling under
appropriate condition. This process is
known as germination.
•Multiple fission: •During unfavourable condition, the amoeba
withdraws its pseudopodia, becomes almost
round and secretes a hard covering called
•Inside the cyst nucleus divides into many
nuclei by repeated division, follow by division
•As a result many daughter cells are formed.
•The cyst bursts to release the daughter cells
during favourable condition.
•Importance of variation.
•Changes in ecological system, which
are beyond our control like varying
temperature, varying water level can
wipe out the population species.
•But, if variations in some individuals
are suitable for new environment,
there is a chance of survival of that