PPT: How do Organisms Reproduce? - Science Class 10

 Page 1


HOW DO ORGANISMS 
REPRODUCE?
Page 2


HOW DO ORGANISMS 
REPRODUCE?
1) Reproduction :-
Reproduction is the process by which living organisms 
produce new individuals of the same species.
Reproduction is necessary for the survival and increase
in the population of a species. If organisms do not 
reproduce, their population decreases and species will 
become extinct.
2) Do organisms create carbon copies of 
themselves ?
The DNA (Deoxyribo nucleic acid) molecules in the
chromosomes in the nucleus is responsible for the transfer 
of characters from the parents to the off springs. During 
reproduction the reproductive cells produce two copies of 
the DNA which separate into two cells. The DNA copies will 
be similar but not identical to each other. So the new 
individuals have slight variations from their parents. This is 
the basis for variations and evolution of new species.
Page 3


HOW DO ORGANISMS 
REPRODUCE?
1) Reproduction :-
Reproduction is the process by which living organisms 
produce new individuals of the same species.
Reproduction is necessary for the survival and increase
in the population of a species. If organisms do not 
reproduce, their population decreases and species will 
become extinct.
2) Do organisms create carbon copies of 
themselves ?
The DNA (Deoxyribo nucleic acid) molecules in the
chromosomes in the nucleus is responsible for the transfer 
of characters from the parents to the off springs. During 
reproduction the reproductive cells produce two copies of 
the DNA which separate into two cells. The DNA copies will 
be similar but not identical to each other. So the new 
individuals have slight variations from their parents. This is 
the basis for variations and evolution of new species.
3) The importance of variation :-
DNA copying during reproduction is important for 
maintaining the body designs of different organisms to 
survive in the existing environment. But the environment is 
constantly changing due to changes in temperature, 
climate, water levels etc. If organisms cannot adjust 
themselves to the changes in the environment then their 
species will become extinct.
If there are variations in some individuals of a species 
they may be able to survive the changes in the 
environment.
So variations in species is necessary for the survival of
different species and for the evolution of new species.
Page 4


HOW DO ORGANISMS 
REPRODUCE?
1) Reproduction :-
Reproduction is the process by which living organisms 
produce new individuals of the same species.
Reproduction is necessary for the survival and increase
in the population of a species. If organisms do not 
reproduce, their population decreases and species will 
become extinct.
2) Do organisms create carbon copies of 
themselves ?
The DNA (Deoxyribo nucleic acid) molecules in the
chromosomes in the nucleus is responsible for the transfer 
of characters from the parents to the off springs. During 
reproduction the reproductive cells produce two copies of 
the DNA which separate into two cells. The DNA copies will 
be similar but not identical to each other. So the new 
individuals have slight variations from their parents. This is 
the basis for variations and evolution of new species.
3) The importance of variation :-
DNA copying during reproduction is important for 
maintaining the body designs of different organisms to 
survive in the existing environment. But the environment is 
constantly changing due to changes in temperature, 
climate, water levels etc. If organisms cannot adjust 
themselves to the changes in the environment then their 
species will become extinct.
If there are variations in some individuals of a species 
they may be able to survive the changes in the 
environment.
So variations in species is necessary for the survival of
different species and for the evolution of new species.
4) Types of reproduction :-
There are two main types of reproduction in living organisms. They 
are asexual reproduction and sexual reproduction.
Asexual reproduction :- is reproduction in which new individuals 
are produced from a single parent.
Sexual reproduction :- is reproduction in which two individuals 
are involved to produce a new individual.
Asexual reproduction is of different types. They are:- fission, 
budding, regeneration, fragmentation, spore formation, vegetative 
propagation etc.
Page 5


HOW DO ORGANISMS 
REPRODUCE?
1) Reproduction :-
Reproduction is the process by which living organisms 
produce new individuals of the same species.
Reproduction is necessary for the survival and increase
in the population of a species. If organisms do not 
reproduce, their population decreases and species will 
become extinct.
2) Do organisms create carbon copies of 
themselves ?
The DNA (Deoxyribo nucleic acid) molecules in the
chromosomes in the nucleus is responsible for the transfer 
of characters from the parents to the off springs. During 
reproduction the reproductive cells produce two copies of 
the DNA which separate into two cells. The DNA copies will 
be similar but not identical to each other. So the new 
individuals have slight variations from their parents. This is 
the basis for variations and evolution of new species.
3) The importance of variation :-
DNA copying during reproduction is important for 
maintaining the body designs of different organisms to 
survive in the existing environment. But the environment is 
constantly changing due to changes in temperature, 
climate, water levels etc. If organisms cannot adjust 
themselves to the changes in the environment then their 
species will become extinct.
If there are variations in some individuals of a species 
they may be able to survive the changes in the 
environment.
So variations in species is necessary for the survival of
different species and for the evolution of new species.
4) Types of reproduction :-
There are two main types of reproduction in living organisms. They 
are asexual reproduction and sexual reproduction.
Asexual reproduction :- is reproduction in which new individuals 
are produced from a single parent.
Sexual reproduction :- is reproduction in which two individuals 
are involved to produce a new individual.
Asexual reproduction is of different types. They are:- fission, 
budding, regeneration, fragmentation, spore formation, vegetative 
propagation etc.
i) Fission :-
Fission is an asexual reproduction by which a unicellular
organism divides and forms two or more new individuals. 
Fission is of two types. They are binary fission and multiple 
fission.
i)Binary fission :- In this method an organism divides and 
forms two individuals. First the nucleus divides and forms 
two nuclei. Then the cytoplasm divides and forms two 
daughter cells. Eg:- Amoeba, Paramaecium etc.
ii) Multiple fission :- In this method one organism divides 
into many daughter cells. Eg.Plasmodium (Malarial parasite).