NCERT Solutions for Class 10 Science How do Organisms Reproduce Ch 8
Chapter 8 : How do Organisms Reproduce?
Class 10 Science : In this article, we will discuss ‘How do Organisms Reproduce’of 10th Class Science. Before understanding how does an organism reproduce, it is important for us to understand why the organism reproduce? Reproduction is necessary to keep the life-process ongoing.
Do organisms create exact copies of themselves?
We will discuss one activity here. Look around in your Class 10 Classroom. You will find that all students have similar body structure. Reproduction is the process, making copies of the blueprints of a body structure.
We know the chromosomes in the nucleus of the cell contain information for the inheritance of features from parents to the next generation in the form of DNA (deoxyribonucleic acid) molecules. The DNA is the information source for making protein. If somehow, this information is changed, then the body design or structure will differ.
Now, as a 10 Class Science student, we know that a basic event in reproduction is the creation of the DNA copies. The chemical reaction of the cell creates two copies of the DNA in a reproducing cell and they will be needed to be separated from each other. The DNA copied is accompanied by the creation of an additional cellular apparatus and then the DNA copies, each with its own apparatus. So, a cell divides to give rise to two cells.
All living organisms reproduce mainly through: –
- Asexual reproduction
- Sexual reproduction
Let’s proceed further and discuss in detail:
- Single celled organisms reproduce through the following ways:-
- Binary Fission
- Multiple Fission
- Spore formation
- Asexual reproduction of multicellular organisms
- Fragmentation and regeneration
- Vegetative propagation
- Natural Vegetative propagation
- Artificial vegetative propagation
The process when the cells in unicellular organisms become fully mature and it gets divided into two or more parts is called Fission.
In organisms like amoeba splitting can take place in any plane, but in some other organisms, binary fusion occurs in a definite orientation.
Other single-celled organisms such as Plasmodium (the malaria parasite) split into many daughter cells at the same time by multiple fission.
The organism like hydra use regenerative cells for reproduction in the process of budding In hydra, the repeated cell division at one specific rate leads to the development of a bud. These buds develop into tiny individuals on maturity the get divided from the parent body and become independent individuals
In this method of reproduction, the parent plant produces hundreds of tiny spores, which can grow into new plants. The microscopic, hard and unaffected figures which are round in shape and can grow into a new plant under appropriate conditions. They are known as Spores.
Spore formation in Rhizopus
When the individual is broken or cut into many pieces, the ability to give rise to a new organism is called regeneration. This process is commonly found in the Hydra and Planaria. The special cells carry out this process. These cells proliferate and make a large number of cells. Different cells undergo changes to become various cell types and tissues.
Regeneration in Hydra
During this process, a filament of Spirogyra simply breaks up into smaller pieces upon maturation. These pieces grow into new individuals.
In this process, the new plant is produced from any vegetative part of the plant such as root, stem, leaf, etc.
In the next article Class 10 Science Notes, we will talk about sexual reproduction.
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