Textbook: Life Processes in Living Organisms Part - 2 | Science and Technology Class 10 (Maharashtra SSC Board) PDF Download

 Page 1


22
Ø Reproduction: Asexual and Sexual reproduction.        
Ø Reproduction and modern technology
Ø	 Reproductive health 	                   
Ø  Population Explosion
3. Life Processes in Living Organisms Part - 2
1. Which are the important life processes in living organisms?
2. Which life processes are essential for production of energy  
 required by body?
3. Which are main types of cell-division? What are the differences?
4. What is the role of chromosomes in cell-division?
 We have studied various life processes in previous classes. All those life processes i.e. 
nutrition, respiration, excretion, sensation & response (control & co-ordination), etc. are 
essential to each living organism to remain alive. Besides these life processes, one more life 
process occurs in living organisms; it is reproduction. However, reproduction does not help 
the organism to remain alive but it helps to maintain the continuity of the species of that 
organism. 
1. What do we mean by maintenance of species?
2. Whether the new organism is genetically exactly similar to earlier one that has produced 
it?
3. Who determines whether the two organism of a species will be exactly similar or not?
4. What is the relationship between the cell division and formation of new organism of 
same species by earlier existing organism?
 Formation of new organism of same species by earlier existing organism is called as 
reproduction. Reproduction is one of the various important characters of living organisms. 
It is also one of the various reasons responsible for evolution of each species. In living 
organisms, reproduction occurs mainly by two methods. Those two methods are- asexual 
and sexual reproduction. 
Asexual reproduction 
Observe the pictures and 
tell the life process which you 
identified.  
a.
b.
c.
d. 
3.1 Some Life processes
Observe
Can you recall?
Can you tell?
Process of formation of new organism by an organism of same species without 
involvement of gametes is called as asexual reproduction. As this reproduction does not 
involve union of two different gametes, the new organism has exact genetic similarity with 
the reproducing organism. This is uniparental reproduction and it occurs by mitotic cell 
division. Absence of genetic recombination is a drawback whereas fast process is advantage 
of this reproductive method.
Page 2


22
Ø Reproduction: Asexual and Sexual reproduction.        
Ø Reproduction and modern technology
Ø	 Reproductive health 	                   
Ø  Population Explosion
3. Life Processes in Living Organisms Part - 2
1. Which are the important life processes in living organisms?
2. Which life processes are essential for production of energy  
 required by body?
3. Which are main types of cell-division? What are the differences?
4. What is the role of chromosomes in cell-division?
 We have studied various life processes in previous classes. All those life processes i.e. 
nutrition, respiration, excretion, sensation & response (control & co-ordination), etc. are 
essential to each living organism to remain alive. Besides these life processes, one more life 
process occurs in living organisms; it is reproduction. However, reproduction does not help 
the organism to remain alive but it helps to maintain the continuity of the species of that 
organism. 
1. What do we mean by maintenance of species?
2. Whether the new organism is genetically exactly similar to earlier one that has produced 
it?
3. Who determines whether the two organism of a species will be exactly similar or not?
4. What is the relationship between the cell division and formation of new organism of 
same species by earlier existing organism?
 Formation of new organism of same species by earlier existing organism is called as 
reproduction. Reproduction is one of the various important characters of living organisms. 
It is also one of the various reasons responsible for evolution of each species. In living 
organisms, reproduction occurs mainly by two methods. Those two methods are- asexual 
and sexual reproduction. 
Asexual reproduction 
Observe the pictures and 
tell the life process which you 
identified.  
a.
b.
c.
d. 
3.1 Some Life processes
Observe
Can you recall?
Can you tell?
Process of formation of new organism by an organism of same species without 
involvement of gametes is called as asexual reproduction. As this reproduction does not 
involve union of two different gametes, the new organism has exact genetic similarity with 
the reproducing organism. This is uniparental reproduction and it occurs by mitotic cell 
division. Absence of genetic recombination is a drawback whereas fast process is advantage 
of this reproductive method.
23
A. Asexual reproduction in unicellular organisms 
1. Binary Fission
Activity 1 : Take a conical flask and collect the 
water in it from a pond having stagnant water 
and aquatic plants. Add some wheat grains 
and aquatic plants to it. Keep it for 3 – 4 days 
so that wheat grains & plants will decompose. 
Early in the morning on fourth day, take a 
glass slide and put a drop of that water over 
it. Carefully, put a cover-slip on that drop and 
observe under compound microscope.
 You will be able to see many paramecia 
performing the binary fission.
 Prokaryotes (Bacteria), Protists (Amoeba, 
Paramecium, Euglena, etc.) and eukaryotic 
cell-organelle like mitochondria and 
chloroplasts perform asexual reproduction by 
binary fission. In this process, the parent cell 
divides to form two similar daughter cells. 
Binary fission occurs either by mitosis or 
amitosis.
 Axis of fission / division is different in 
different protists. Ex.: Amoeba divides in any 
plane due to lack of specific shape; hence it is 
called as ‘simple binary fission’. Paramecium 
divides by   ‘transverse binary fission’ whereas 
Euglena by ‘longitudinal binary fission’. 
 Binary fission is usually performed by 
living organisms during favourable conditions 
i.e. availability of abundant food material.
2. Multiple Fission
 Asexual reproduction by multiple fission is performed by Amoeba and other similar 
protists. Amoeba stops the formation of pseudopodia and thereby movements whenever 
there is lack of food or any other type of adverse condition. It becomes rounded and forms 
protective covering around plasma membrane. Such encysted Amoeba or any other protist 
is called as ‘Cyst’.
 Many nuclei are formed by repeated nuclear divisions in the cyst. It is followed by 
cytoplasmic division and thus, many amoebulae are formed. They remain encysted till 
there are adverse conditions. Cyst breaks open on arrival of favourable conditions and 
many amoebulae are released.
3.2   Simple binary fission: Amoeba 
3.3 Transverse binary fission : Paramecium 
3.4  Longitudinal binary fission: Euglena 
Parent Amoeba 
Daughter  Amoeba 
Parent Paramecium 
Daughter 
Paramecium 
Try this
Page 3


22
Ø Reproduction: Asexual and Sexual reproduction.        
Ø Reproduction and modern technology
Ø	 Reproductive health 	                   
Ø  Population Explosion
3. Life Processes in Living Organisms Part - 2
1. Which are the important life processes in living organisms?
2. Which life processes are essential for production of energy  
 required by body?
3. Which are main types of cell-division? What are the differences?
4. What is the role of chromosomes in cell-division?
 We have studied various life processes in previous classes. All those life processes i.e. 
nutrition, respiration, excretion, sensation & response (control & co-ordination), etc. are 
essential to each living organism to remain alive. Besides these life processes, one more life 
process occurs in living organisms; it is reproduction. However, reproduction does not help 
the organism to remain alive but it helps to maintain the continuity of the species of that 
organism. 
1. What do we mean by maintenance of species?
2. Whether the new organism is genetically exactly similar to earlier one that has produced 
it?
3. Who determines whether the two organism of a species will be exactly similar or not?
4. What is the relationship between the cell division and formation of new organism of 
same species by earlier existing organism?
 Formation of new organism of same species by earlier existing organism is called as 
reproduction. Reproduction is one of the various important characters of living organisms. 
It is also one of the various reasons responsible for evolution of each species. In living 
organisms, reproduction occurs mainly by two methods. Those two methods are- asexual 
and sexual reproduction. 
Asexual reproduction 
Observe the pictures and 
tell the life process which you 
identified.  
a.
b.
c.
d. 
3.1 Some Life processes
Observe
Can you recall?
Can you tell?
Process of formation of new organism by an organism of same species without 
involvement of gametes is called as asexual reproduction. As this reproduction does not 
involve union of two different gametes, the new organism has exact genetic similarity with 
the reproducing organism. This is uniparental reproduction and it occurs by mitotic cell 
division. Absence of genetic recombination is a drawback whereas fast process is advantage 
of this reproductive method.
23
A. Asexual reproduction in unicellular organisms 
1. Binary Fission
Activity 1 : Take a conical flask and collect the 
water in it from a pond having stagnant water 
and aquatic plants. Add some wheat grains 
and aquatic plants to it. Keep it for 3 – 4 days 
so that wheat grains & plants will decompose. 
Early in the morning on fourth day, take a 
glass slide and put a drop of that water over 
it. Carefully, put a cover-slip on that drop and 
observe under compound microscope.
 You will be able to see many paramecia 
performing the binary fission.
 Prokaryotes (Bacteria), Protists (Amoeba, 
Paramecium, Euglena, etc.) and eukaryotic 
cell-organelle like mitochondria and 
chloroplasts perform asexual reproduction by 
binary fission. In this process, the parent cell 
divides to form two similar daughter cells. 
Binary fission occurs either by mitosis or 
amitosis.
 Axis of fission / division is different in 
different protists. Ex.: Amoeba divides in any 
plane due to lack of specific shape; hence it is 
called as ‘simple binary fission’. Paramecium 
divides by   ‘transverse binary fission’ whereas 
Euglena by ‘longitudinal binary fission’. 
 Binary fission is usually performed by 
living organisms during favourable conditions 
i.e. availability of abundant food material.
2. Multiple Fission
 Asexual reproduction by multiple fission is performed by Amoeba and other similar 
protists. Amoeba stops the formation of pseudopodia and thereby movements whenever 
there is lack of food or any other type of adverse condition. It becomes rounded and forms 
protective covering around plasma membrane. Such encysted Amoeba or any other protist 
is called as ‘Cyst’.
 Many nuclei are formed by repeated nuclear divisions in the cyst. It is followed by 
cytoplasmic division and thus, many amoebulae are formed. They remain encysted till 
there are adverse conditions. Cyst breaks open on arrival of favourable conditions and 
many amoebulae are released.
3.2   Simple binary fission: Amoeba 
3.3 Transverse binary fission : Paramecium 
3.4  Longitudinal binary fission: Euglena 
Parent Amoeba 
Daughter  Amoeba 
Parent Paramecium 
Daughter 
Paramecium 
Try this
24
 Does the parent 
cell exist after asexual 
reproduction- fission?
3. Budding:
Activity 2 : Bring the active dry yeast 
powder from market. Take 50 ml 
lukewarm water in a conical flask. Add 
5 gm of active dry yeast powder and 10 
gm table sugar to that water and mix 
well the mixture. Keep the flask in warm 
place and after an hour take a drop of 
that mixture on a clean glass slide. Put 
a cover-glass on that drop and observe it 
under the compound microscope.
 You will see the yeast cells performing budding i.e. a small bud coming  out of many 
parent cells. Asexual reproduction occurs by budding in yeast- a unicellular fungus.  Yeast 
cell produces two daughter nuclei by mitotic division, so as to reproduce by budding.  This 
yeast cell is called as parent cell. A small bulge appears on the surface of parent cell. This 
bulge is actually a bud. One of the two daughter nuclei enters this bud. After sufficient 
growth, bud separates from the parent cell and starts to live independently as a daughter 
yeast cell.
B.  Asexual reproduction in Multicellular organisms
1. Fragmentation:
 This type of asexual reproduction occurs in multicellular 
organisms. In this type of reproduction, the body of parent 
organism breaks up into many fragments and each fragment 
starts to live as an independent new organism. This type of 
reproduction occurs in algae like Spirogyra, and sponges like 
Sycon.
 Whenever there is plenty of water and nutrients are 
available to Spirogyra, its filaments grow up very fast and 
break up into many small fragments. Each fragment starts 
to live independently as a new Spirogyra fiber.If the body 
of Sycon breaks up accidentally into many fragments, each 
fragment develops into new Sycon.
2. Regeneration
 You may know that the wall lizard breaks up and 
discards some part of its tail in emergency. Discarded part 
is regenerated after a period. This is an example of limited 
regeneration. However, under certain situations, an animal- 
Planaria breaks up its body into two parts and thereafter each 
part regenerates remaining part of the body and thus two new 
Planaria are formed. This is called as regeneration.
Spirogyra 
Division of nucleus and 
cytoplasm
Daughter 
amoeba 
3.5  Multiple fission
3.6  Budding
3.7  Fragmentation 
Parent Amoeba 
3.8 Regeneration
Use your brain power
Cyst 
Bulge 
Daughter 
yeast 
New Bud 
Parent yeast
      cell 
Page 4


22
Ø Reproduction: Asexual and Sexual reproduction.        
Ø Reproduction and modern technology
Ø	 Reproductive health 	                   
Ø  Population Explosion
3. Life Processes in Living Organisms Part - 2
1. Which are the important life processes in living organisms?
2. Which life processes are essential for production of energy  
 required by body?
3. Which are main types of cell-division? What are the differences?
4. What is the role of chromosomes in cell-division?
 We have studied various life processes in previous classes. All those life processes i.e. 
nutrition, respiration, excretion, sensation & response (control & co-ordination), etc. are 
essential to each living organism to remain alive. Besides these life processes, one more life 
process occurs in living organisms; it is reproduction. However, reproduction does not help 
the organism to remain alive but it helps to maintain the continuity of the species of that 
organism. 
1. What do we mean by maintenance of species?
2. Whether the new organism is genetically exactly similar to earlier one that has produced 
it?
3. Who determines whether the two organism of a species will be exactly similar or not?
4. What is the relationship between the cell division and formation of new organism of 
same species by earlier existing organism?
 Formation of new organism of same species by earlier existing organism is called as 
reproduction. Reproduction is one of the various important characters of living organisms. 
It is also one of the various reasons responsible for evolution of each species. In living 
organisms, reproduction occurs mainly by two methods. Those two methods are- asexual 
and sexual reproduction. 
Asexual reproduction 
Observe the pictures and 
tell the life process which you 
identified.  
a.
b.
c.
d. 
3.1 Some Life processes
Observe
Can you recall?
Can you tell?
Process of formation of new organism by an organism of same species without 
involvement of gametes is called as asexual reproduction. As this reproduction does not 
involve union of two different gametes, the new organism has exact genetic similarity with 
the reproducing organism. This is uniparental reproduction and it occurs by mitotic cell 
division. Absence of genetic recombination is a drawback whereas fast process is advantage 
of this reproductive method.
23
A. Asexual reproduction in unicellular organisms 
1. Binary Fission
Activity 1 : Take a conical flask and collect the 
water in it from a pond having stagnant water 
and aquatic plants. Add some wheat grains 
and aquatic plants to it. Keep it for 3 – 4 days 
so that wheat grains & plants will decompose. 
Early in the morning on fourth day, take a 
glass slide and put a drop of that water over 
it. Carefully, put a cover-slip on that drop and 
observe under compound microscope.
 You will be able to see many paramecia 
performing the binary fission.
 Prokaryotes (Bacteria), Protists (Amoeba, 
Paramecium, Euglena, etc.) and eukaryotic 
cell-organelle like mitochondria and 
chloroplasts perform asexual reproduction by 
binary fission. In this process, the parent cell 
divides to form two similar daughter cells. 
Binary fission occurs either by mitosis or 
amitosis.
 Axis of fission / division is different in 
different protists. Ex.: Amoeba divides in any 
plane due to lack of specific shape; hence it is 
called as ‘simple binary fission’. Paramecium 
divides by   ‘transverse binary fission’ whereas 
Euglena by ‘longitudinal binary fission’. 
 Binary fission is usually performed by 
living organisms during favourable conditions 
i.e. availability of abundant food material.
2. Multiple Fission
 Asexual reproduction by multiple fission is performed by Amoeba and other similar 
protists. Amoeba stops the formation of pseudopodia and thereby movements whenever 
there is lack of food or any other type of adverse condition. It becomes rounded and forms 
protective covering around plasma membrane. Such encysted Amoeba or any other protist 
is called as ‘Cyst’.
 Many nuclei are formed by repeated nuclear divisions in the cyst. It is followed by 
cytoplasmic division and thus, many amoebulae are formed. They remain encysted till 
there are adverse conditions. Cyst breaks open on arrival of favourable conditions and 
many amoebulae are released.
3.2   Simple binary fission: Amoeba 
3.3 Transverse binary fission : Paramecium 
3.4  Longitudinal binary fission: Euglena 
Parent Amoeba 
Daughter  Amoeba 
Parent Paramecium 
Daughter 
Paramecium 
Try this
24
 Does the parent 
cell exist after asexual 
reproduction- fission?
3. Budding:
Activity 2 : Bring the active dry yeast 
powder from market. Take 50 ml 
lukewarm water in a conical flask. Add 
5 gm of active dry yeast powder and 10 
gm table sugar to that water and mix 
well the mixture. Keep the flask in warm 
place and after an hour take a drop of 
that mixture on a clean glass slide. Put 
a cover-glass on that drop and observe it 
under the compound microscope.
 You will see the yeast cells performing budding i.e. a small bud coming  out of many 
parent cells. Asexual reproduction occurs by budding in yeast- a unicellular fungus.  Yeast 
cell produces two daughter nuclei by mitotic division, so as to reproduce by budding.  This 
yeast cell is called as parent cell. A small bulge appears on the surface of parent cell. This 
bulge is actually a bud. One of the two daughter nuclei enters this bud. After sufficient 
growth, bud separates from the parent cell and starts to live independently as a daughter 
yeast cell.
B.  Asexual reproduction in Multicellular organisms
1. Fragmentation:
 This type of asexual reproduction occurs in multicellular 
organisms. In this type of reproduction, the body of parent 
organism breaks up into many fragments and each fragment 
starts to live as an independent new organism. This type of 
reproduction occurs in algae like Spirogyra, and sponges like 
Sycon.
 Whenever there is plenty of water and nutrients are 
available to Spirogyra, its filaments grow up very fast and 
break up into many small fragments. Each fragment starts 
to live independently as a new Spirogyra fiber.If the body 
of Sycon breaks up accidentally into many fragments, each 
fragment develops into new Sycon.
2. Regeneration
 You may know that the wall lizard breaks up and 
discards some part of its tail in emergency. Discarded part 
is regenerated after a period. This is an example of limited 
regeneration. However, under certain situations, an animal- 
Planaria breaks up its body into two parts and thereafter each 
part regenerates remaining part of the body and thus two new 
Planaria are formed. This is called as regeneration.
Spirogyra 
Division of nucleus and 
cytoplasm
Daughter 
amoeba 
3.5  Multiple fission
3.6  Budding
3.7  Fragmentation 
Parent Amoeba 
3.8 Regeneration
Use your brain power
Cyst 
Bulge 
Daughter 
yeast 
New Bud 
Parent yeast
      cell 
25
3. Budding
 In case of Hydra, under favourable 
conditions, at specific part of its body, an 
outgrowth is formed by repeated divisions of 
regenerative cells of body wall. This outgrowth 
is called as bud. Bud grows up progressively 
and finally forms a small hydra. Dermal layers 
and digestive cavity of the budding hydra are 
in continuity with those of parent hydra. Parent 
hydra supplies nutrition to the budding hydra. 
Budding hydra separates from parent hydra and 
starts to lead an independent life when it grows 
up and becomes able to lead an independent life. 
4. Vegetative Propagation
 Reproduction in plants with the help of 
vegetative parts like root, stem, leaf and bud is 
called as vegetative reproduction. Vegetative 
propagation in potatoes is performed with 
the help of ‘eyes’ present on tuber whereas in 
Bryophyllum it is performed with the help of buds 
present on leaf margin. In case of plants like 
sugarcane & grasses, vegetative propagation 
occurs with the help of buds present on nodes. 
5. Spore Formation
 Take a piece of wet bread or ‘bhakari’ and 
keep it in humid place. Fungus will grow on it 
within 2 – 3 days. Observe the fungus under 
compound microscope and draw its diagram.
 Fungi like Mucor have filamentous body. They 
have sporangia. Once the spores are formed, 
sporangia burst and spores are released. Spores 
germinate in moist and warm place and new 
fungal colony is formed.
Sweet 
Potato 
Bryophyllum  
Potato 
Hydra
Bud 
Nascent Hydra 
3.9 Budding  
3.10 Vegetative 
reproduction
Sexual Reproduction 
 Sexual reproduction always occurs with the help of two germ cells. Female gamete and 
male gamete are those two germ cells. Two main processes occur in the sexual reproduction.
1. Gamete formation: Gametes are formed by the meiosis. In meiosis, chromosome 
number is reduced to half; hence haploid gametes are formed. 
Sporangium 
Spores
Hyphae 
Rhizoid  
Piece of bread   
Greenish 
Layer 
3.11  Spore formation 
Try this
Page 5


22
Ø Reproduction: Asexual and Sexual reproduction.        
Ø Reproduction and modern technology
Ø	 Reproductive health 	                   
Ø  Population Explosion
3. Life Processes in Living Organisms Part - 2
1. Which are the important life processes in living organisms?
2. Which life processes are essential for production of energy  
 required by body?
3. Which are main types of cell-division? What are the differences?
4. What is the role of chromosomes in cell-division?
 We have studied various life processes in previous classes. All those life processes i.e. 
nutrition, respiration, excretion, sensation & response (control & co-ordination), etc. are 
essential to each living organism to remain alive. Besides these life processes, one more life 
process occurs in living organisms; it is reproduction. However, reproduction does not help 
the organism to remain alive but it helps to maintain the continuity of the species of that 
organism. 
1. What do we mean by maintenance of species?
2. Whether the new organism is genetically exactly similar to earlier one that has produced 
it?
3. Who determines whether the two organism of a species will be exactly similar or not?
4. What is the relationship between the cell division and formation of new organism of 
same species by earlier existing organism?
 Formation of new organism of same species by earlier existing organism is called as 
reproduction. Reproduction is one of the various important characters of living organisms. 
It is also one of the various reasons responsible for evolution of each species. In living 
organisms, reproduction occurs mainly by two methods. Those two methods are- asexual 
and sexual reproduction. 
Asexual reproduction 
Observe the pictures and 
tell the life process which you 
identified.  
a.
b.
c.
d. 
3.1 Some Life processes
Observe
Can you recall?
Can you tell?
Process of formation of new organism by an organism of same species without 
involvement of gametes is called as asexual reproduction. As this reproduction does not 
involve union of two different gametes, the new organism has exact genetic similarity with 
the reproducing organism. This is uniparental reproduction and it occurs by mitotic cell 
division. Absence of genetic recombination is a drawback whereas fast process is advantage 
of this reproductive method.
23
A. Asexual reproduction in unicellular organisms 
1. Binary Fission
Activity 1 : Take a conical flask and collect the 
water in it from a pond having stagnant water 
and aquatic plants. Add some wheat grains 
and aquatic plants to it. Keep it for 3 – 4 days 
so that wheat grains & plants will decompose. 
Early in the morning on fourth day, take a 
glass slide and put a drop of that water over 
it. Carefully, put a cover-slip on that drop and 
observe under compound microscope.
 You will be able to see many paramecia 
performing the binary fission.
 Prokaryotes (Bacteria), Protists (Amoeba, 
Paramecium, Euglena, etc.) and eukaryotic 
cell-organelle like mitochondria and 
chloroplasts perform asexual reproduction by 
binary fission. In this process, the parent cell 
divides to form two similar daughter cells. 
Binary fission occurs either by mitosis or 
amitosis.
 Axis of fission / division is different in 
different protists. Ex.: Amoeba divides in any 
plane due to lack of specific shape; hence it is 
called as ‘simple binary fission’. Paramecium 
divides by   ‘transverse binary fission’ whereas 
Euglena by ‘longitudinal binary fission’. 
 Binary fission is usually performed by 
living organisms during favourable conditions 
i.e. availability of abundant food material.
2. Multiple Fission
 Asexual reproduction by multiple fission is performed by Amoeba and other similar 
protists. Amoeba stops the formation of pseudopodia and thereby movements whenever 
there is lack of food or any other type of adverse condition. It becomes rounded and forms 
protective covering around plasma membrane. Such encysted Amoeba or any other protist 
is called as ‘Cyst’.
 Many nuclei are formed by repeated nuclear divisions in the cyst. It is followed by 
cytoplasmic division and thus, many amoebulae are formed. They remain encysted till 
there are adverse conditions. Cyst breaks open on arrival of favourable conditions and 
many amoebulae are released.
3.2   Simple binary fission: Amoeba 
3.3 Transverse binary fission : Paramecium 
3.4  Longitudinal binary fission: Euglena 
Parent Amoeba 
Daughter  Amoeba 
Parent Paramecium 
Daughter 
Paramecium 
Try this
24
 Does the parent 
cell exist after asexual 
reproduction- fission?
3. Budding:
Activity 2 : Bring the active dry yeast 
powder from market. Take 50 ml 
lukewarm water in a conical flask. Add 
5 gm of active dry yeast powder and 10 
gm table sugar to that water and mix 
well the mixture. Keep the flask in warm 
place and after an hour take a drop of 
that mixture on a clean glass slide. Put 
a cover-glass on that drop and observe it 
under the compound microscope.
 You will see the yeast cells performing budding i.e. a small bud coming  out of many 
parent cells. Asexual reproduction occurs by budding in yeast- a unicellular fungus.  Yeast 
cell produces two daughter nuclei by mitotic division, so as to reproduce by budding.  This 
yeast cell is called as parent cell. A small bulge appears on the surface of parent cell. This 
bulge is actually a bud. One of the two daughter nuclei enters this bud. After sufficient 
growth, bud separates from the parent cell and starts to live independently as a daughter 
yeast cell.
B.  Asexual reproduction in Multicellular organisms
1. Fragmentation:
 This type of asexual reproduction occurs in multicellular 
organisms. In this type of reproduction, the body of parent 
organism breaks up into many fragments and each fragment 
starts to live as an independent new organism. This type of 
reproduction occurs in algae like Spirogyra, and sponges like 
Sycon.
 Whenever there is plenty of water and nutrients are 
available to Spirogyra, its filaments grow up very fast and 
break up into many small fragments. Each fragment starts 
to live independently as a new Spirogyra fiber.If the body 
of Sycon breaks up accidentally into many fragments, each 
fragment develops into new Sycon.
2. Regeneration
 You may know that the wall lizard breaks up and 
discards some part of its tail in emergency. Discarded part 
is regenerated after a period. This is an example of limited 
regeneration. However, under certain situations, an animal- 
Planaria breaks up its body into two parts and thereafter each 
part regenerates remaining part of the body and thus two new 
Planaria are formed. This is called as regeneration.
Spirogyra 
Division of nucleus and 
cytoplasm
Daughter 
amoeba 
3.5  Multiple fission
3.6  Budding
3.7  Fragmentation 
Parent Amoeba 
3.8 Regeneration
Use your brain power
Cyst 
Bulge 
Daughter 
yeast 
New Bud 
Parent yeast
      cell 
25
3. Budding
 In case of Hydra, under favourable 
conditions, at specific part of its body, an 
outgrowth is formed by repeated divisions of 
regenerative cells of body wall. This outgrowth 
is called as bud. Bud grows up progressively 
and finally forms a small hydra. Dermal layers 
and digestive cavity of the budding hydra are 
in continuity with those of parent hydra. Parent 
hydra supplies nutrition to the budding hydra. 
Budding hydra separates from parent hydra and 
starts to lead an independent life when it grows 
up and becomes able to lead an independent life. 
4. Vegetative Propagation
 Reproduction in plants with the help of 
vegetative parts like root, stem, leaf and bud is 
called as vegetative reproduction. Vegetative 
propagation in potatoes is performed with 
the help of ‘eyes’ present on tuber whereas in 
Bryophyllum it is performed with the help of buds 
present on leaf margin. In case of plants like 
sugarcane & grasses, vegetative propagation 
occurs with the help of buds present on nodes. 
5. Spore Formation
 Take a piece of wet bread or ‘bhakari’ and 
keep it in humid place. Fungus will grow on it 
within 2 – 3 days. Observe the fungus under 
compound microscope and draw its diagram.
 Fungi like Mucor have filamentous body. They 
have sporangia. Once the spores are formed, 
sporangia burst and spores are released. Spores 
germinate in moist and warm place and new 
fungal colony is formed.
Sweet 
Potato 
Bryophyllum  
Potato 
Hydra
Bud 
Nascent Hydra 
3.9 Budding  
3.10 Vegetative 
reproduction
Sexual Reproduction 
 Sexual reproduction always occurs with the help of two germ cells. Female gamete and 
male gamete are those two germ cells. Two main processes occur in the sexual reproduction.
1. Gamete formation: Gametes are formed by the meiosis. In meiosis, chromosome 
number is reduced to half; hence haploid gametes are formed. 
Sporangium 
Spores
Hyphae 
Rhizoid  
Piece of bread   
Greenish 
Layer 
3.11  Spore formation 
Try this
26
Let’s Think
Ovary 
Filament 
Male 
flower 
Female
 flower 
3.12  Parts of flower 
3.13  Papaya Flower 
2. Fertilization: A diploid zygote is formed in this process by union of haploid male and 
female gametes. The zygote divides by mitosis and embryo is formed. The embryo develops 
to form new individual.
 Two parents i.e. male parent and female parent are involved in this type of reproduction. 
Fusion of male gamete of male parent and female gamete of female parent occurs. Due to 
this, new individual always has the recombined genes of both the parents. Hence, the new 
individual shows similarities with the parents for some characters and has some characters 
different than both parents. Diversity in living organisms occurs due to genetic variation. 
Genetic variation helps the organisms to adjust with the changing environment and thereby 
to maintain their existence. Due to this, plants and animals can save themselves from being 
extinct.
1. What would have been happened if the male and female gametes
     had been diploid?
2. What would have been happened if any of the cells in nature had 
     not been divided by meiosis?
A. Sexual reproduction in plants 
 Flower is structural unit of sexual reproduction in plants. It consists of four floral whorls 
as calyx, corolla, androecium and gynaecium; arranged in sequence from outside to inside. 
Androecium and gynoecium are called ‘essential whorls’ because they perform the function 
of reproduction whereas calyx and corolla are called as ‘accessory whorls’ because they are 
responsible for protection of inner whorls. Members of calyx are called as ‘sepals’ and they 
are green coloured. Members of corolla are called as ‘petals’ and they are variously colored.
 A flower is called as ‘bisexual’ if both whorls i.e. androecium and gynoecium are 
present in the same flower. Ex. Hibiscus. A flower is called as ‘unisexual’ if any one of 
the abovementioned two whorls is present in the flower. If only androecium is present, it is 
‘male flower’ and if only gynoecium is present, flower is ‘female flower’. Ex. Papaya.   
Corolla (Petals)
Stigma
Style
Anther
Calyx 
(Sepals)
Pedicel
Androecium
Gynoecium