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ScienceClass 10How do Organisms

How do Organisms | Class 10 Science Notes

By ConceptScroll Team · Published on 17 July 2026 · 3 min read

How do Organisms – this guide gives you a concise, exam-ready overview of How do Organisms from Class 10 Science, written by ConceptScroll editors and reviewed against the latest NCERT textbook.

7.2 MODES OF REPRODUCTION USED BY SINGLE ORGANISMS

Single-celled and simple multicellular organisms reproduce using various modes depending on their body design. Unicellular organisms reproduce mainly by cell division or fission, where one cell divides to form two or more daughter cells. Different patterns of fission exist: binary fission, where a cell splits into two equal halves, and multiple fission, where many daughter cells are produced simultaneously. For example, bacteria and protozoa like Amoeba reproduce by binary fission, while Plasmodium reproduces by multiple fission. Yeast reproduces by budding, where a small outgrowth forms and detaches to become a new individual. In multicellular organisms with simple body organization like Spirogyra, reproduction can occur by fragmentation, where the organism breaks into fragments that grow into new individuals. Regeneration is another mode where organisms like Hydra and Planaria can regrow complete individuals from body parts. Budding is a specialized form of regeneration used by Hydra for reproduction. Vegetative propagation is common in plants where parts like roots, stems, or leaves develop into new plants. Spore formation is a reproductive strategy in fungi like Rhizopus, where spores with thick walls are produced to survive harsh conditions and grow into new individuals. All these modes are examples of asexual reproduction, where new generations arise from a single parent without the involvement of gametes.

📊 Diagram: [figure_1] [figure_2] [figure_3] [figure_4] [figure_5] [figure_6] [figure_7] Figure 7.1(a) Binary fission in Amoeba; Figure 7.1(b) Binary fission in Leishmania; Figure 7.2 Multiple fission in Plasmodium; Figure 7.3 Regeneration in Planaria; Figure 7.4 Budding in Hydra; Figure 7.5; Figure 7.6

🧪 Activity: Activity 7.1: Yeast budding observation under microscope; Activity 7.2: Observing mould growth on bread; Activity 7.3: Observing Amoeba and its binary fission; Activity 7.4: Observing Spirogyra filaments; Activity 7.5: Potato buds growing into shoots; Activity 7.6: Money plant cuttings in water.

🔗 Connection: This section on asexual reproduction leads to the discussion of sexual reproduction, which involves two individuals and creates greater variation.

Frequently asked questions

1. What is the importance of DNA copying in reproduction?

DNA copying is crucial in reproduction because it ensures that the genetic information is accurately passed from the parent organism to the offspring. This copying allows the offspring to inherit traits and characteristics of the parent, maintaining the continuity of species. Without DNA copying, reproduction would not result in offspring with the same genetic makeup, leading to loss of hereditary information.

2. Why is variation beneficial to the species but not necessarily for the individual?

Variation is beneficial to a species because it increases the genetic diversity within the population, which helps the species adapt to changing environments and survive over time. Different traits may provide advantages under different conditions, ensuring the species' survival. However, for an individual, variation may not always be beneficial because some variations can be harmful or disadvantageous, reducing the individual's chances of survival or reproduction.

3. Can you think of reasons why more complex organisms cannot give rise to new individuals through regeneration?

More complex organisms have highly specialised tissues and organs that perform specific functions. Regeneration requires the ability to regrow entire body parts or whole organisms from fragments. In complex organisms, cells are differentiated and cannot revert to a pluripotent state easily, limiting their ability to regenerate whole new individuals. Additionally, the complexity of body organisation and the need for precise coordination of multiple systems make regeneration of a whole organism un

4. Why is vegetative propagation practised for growing some types of plants?

Vegetative propagation is practised because it allows the production of new plants that are genetically identical to the parent plant, ensuring the preservation of desired traits. It is also faster than growing plants from seeds and can be used to propagate plants that do not produce viable seeds or have seeds that take a long time to germinate.

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