How Do Organisms Reproduce?
Fission, Budding, Fragmentation and Regeneration | Class 10 Science | CBSE + Foundation + Competitive
Fission, Budding, Fragmentation and Regeneration
1. Introduction | परिचय
English:
Asexual reproduction is a type of reproduction in which generally only one parent is involved and there is no fusion of male and female gametes. In many simple organisms, a new organism can be produced by simple changes in the body of the parent organism. Four important methods discussed here are:
अलैंगिक जनन (Asexual Reproduction) में सामान्यतः केवल एक जनक भाग लेता है और नर तथा मादा युग्मकों का संलयन नहीं होता। कुछ सरल जीवों में जनक के शरीर में होने वाले परिवर्तन से नया जीव उत्पन्न हो सकता है।
Asexual reproduction is a type of reproduction in which generally only one parent is involved and there is no fusion of male and female gametes. In many simple organisms, a new organism can be produced by simple changes in the body of the parent organism. Four important methods discussed here are:
- Fission
- Budding
- Fragmentation
- Regeneration
अलैंगिक जनन (Asexual Reproduction) में सामान्यतः केवल एक जनक भाग लेता है और नर तथा मादा युग्मकों का संलयन नहीं होता। कुछ सरल जीवों में जनक के शरीर में होने वाले परिवर्तन से नया जीव उत्पन्न हो सकता है।
Parent Organism
→
DNA Copying
→
Body Division / Growth
→
New Organism
2. Role of DNA Copying | DNA प्रतिकृति की भूमिका
English:
Before reproduction, genetic material (DNA) must be copied. The copied DNA is passed to the new organism. DNA copying is not perfectly accurate. Small differences may arise during copying. These differences are called variations. Therefore:
जनन से पहले आनुवंशिक पदार्थ (DNA) की प्रतिकृति बनती है। DNA की प्रतिकृति हमेशा पूर्ण रूप से समान नहीं होती। छोटी-छोटी भिन्नताएँ उत्पन्न हो सकती हैं, जिन्हें विविधताएँ (Variations) कहते हैं।
Before reproduction, genetic material (DNA) must be copied. The copied DNA is passed to the new organism. DNA copying is not perfectly accurate. Small differences may arise during copying. These differences are called variations. Therefore:
DNA Copying → Small Variations → Differences among Offspring
हिन्दी:जनन से पहले आनुवंशिक पदार्थ (DNA) की प्रतिकृति बनती है। DNA की प्रतिकृति हमेशा पूर्ण रूप से समान नहीं होती। छोटी-छोटी भिन्नताएँ उत्पन्न हो सकती हैं, जिन्हें विविधताएँ (Variations) कहते हैं।
3. Fission | द्विखंडन / बहुखंडन
English:
Fission is a form of asexual reproduction in which a single parent organism divides to form new individuals. The word fission means splitting or division. Fission can be mainly of two types:
फिशन वह अलैंगिक जनन विधि है जिसमें एक जनक जीव विभाजित होकर नए जीव बनाता है।
Fission is a form of asexual reproduction in which a single parent organism divides to form new individuals. The word fission means splitting or division. Fission can be mainly of two types:
- Binary fission – one organism divides into two daughter organisms.
- Multiple fission – one organism produces many daughter organisms.
फिशन वह अलैंगिक जनन विधि है जिसमें एक जनक जीव विभाजित होकर नए जीव बनाता है।
4. Binary Fission in Amoeba | अमीबा में द्विखंडन
English:
In binary fission, the parent cell divides into two daughter cells. Amoeba commonly reproduces by binary fission. The nucleus divides first, followed by division of the cytoplasm. हिन्दी:
द्विखंडन में एक जनक कोशिका दो पुत्री कोशिकाओं में विभाजित होती है। अमीबा में द्विखंडन सामान्य अलैंगिक जनन विधि है। पहले केंद्रक का विभाजन होता है और उसके बाद कोशिकाद्रव्य विभाजित होता है।
In binary fission, the parent cell divides into two daughter cells. Amoeba commonly reproduces by binary fission. The nucleus divides first, followed by division of the cytoplasm. हिन्दी:
द्विखंडन में एक जनक कोशिका दो पुत्री कोशिकाओं में विभाजित होती है। अमीबा में द्विखंडन सामान्य अलैंगिक जनन विधि है। पहले केंद्रक का विभाजन होता है और उसके बाद कोशिकाद्रव्य विभाजित होता है।
Animated Diagram – Binary Fission in Amoeba
1 Parent Amoeba → 2 Daughter Amoebae
5. Multiple Fission | बहुखंडन
English:
In multiple fission, the nucleus divides repeatedly and the cytoplasm eventually separates to form many daughter organisms. Example: Plasmodium. Under favourable conditions, Plasmodium can multiply rapidly through multiple fission. हिन्दी:
बहुखंडन में जनक जीव का केंद्रक कई बार विभाजित होता है और बाद में कोशिकाद्रव्य अलग होकर अनेक संतति जीव बनाता है। उदाहरण: प्लाज्मोडियम।
In multiple fission, the nucleus divides repeatedly and the cytoplasm eventually separates to form many daughter organisms. Example: Plasmodium. Under favourable conditions, Plasmodium can multiply rapidly through multiple fission. हिन्दी:
बहुखंडन में जनक जीव का केंद्रक कई बार विभाजित होता है और बाद में कोशिकाद्रव्य अलग होकर अनेक संतति जीव बनाता है। उदाहरण: प्लाज्मोडियम।
CBSE Point: Binary fission produces two daughter cells, while multiple fission produces many daughter cells.
6. Budding | मुकुलन
English:
Budding is an asexual reproduction method in which a small outgrowth called a bud develops on the parent body. The bud grows gradually and may eventually detach from the parent to form an independent organism. Examples: Hydra and Yeast. हिन्दी:
मुकुलन में जनक जीव के शरीर पर एक छोटी संरचना विकसित होती है जिसे मुकुल (Bud) कहते हैं। यह मुकुल धीरे-धीरे बढ़ता है और अंत में अलग होकर स्वतंत्र जीव बन सकता है। उदाहरण: हाइड्रा और यीस्ट।
Budding is an asexual reproduction method in which a small outgrowth called a bud develops on the parent body. The bud grows gradually and may eventually detach from the parent to form an independent organism. Examples: Hydra and Yeast. हिन्दी:
मुकुलन में जनक जीव के शरीर पर एक छोटी संरचना विकसित होती है जिसे मुकुल (Bud) कहते हैं। यह मुकुल धीरे-धीरे बढ़ता है और अंत में अलग होकर स्वतंत्र जीव बन सकता है। उदाहरण: हाइड्रा और यीस्ट।
Animated Diagram – Budding in Hydra
Steps of budding:
- Small bud develops on parent.
- Cells of bud divide and grow.
- Bud develops structures similar to parent.
- Bud may detach and become independent.
7. Budding in Yeast | यीस्ट में मुकुलन
Yeast is a unicellular fungus.
During budding, a small outgrowth develops on the yeast cell.
The nucleus divides and one daughter nucleus enters the bud.
The bud enlarges and may separate from the parent cell.
Yeast Cell → Bud Formation → Bud Growth → Daughter Cell
8. Fragmentation | विखंडन
English:
Fragmentation is an asexual reproduction method in which the body of an organism breaks into two or more fragments. Each suitable fragment can grow into a complete organism. Example: Spirogyra. Spirogyra is a filamentous green alga. When its filament breaks into pieces, each suitable fragment can develop into a new Spirogyra filament. हिन्दी:
विखंडन में किसी जीव का शरीर दो या अधिक टुकड़ों में टूट जाता है और प्रत्येक उपयुक्त टुकड़ा नया जीव बना सकता है। उदाहरण: स्पाइरोगाइरा।
Fragmentation is an asexual reproduction method in which the body of an organism breaks into two or more fragments. Each suitable fragment can grow into a complete organism. Example: Spirogyra. Spirogyra is a filamentous green alga. When its filament breaks into pieces, each suitable fragment can develop into a new Spirogyra filament. हिन्दी:
विखंडन में किसी जीव का शरीर दो या अधिक टुकड़ों में टूट जाता है और प्रत्येक उपयुक्त टुकड़ा नया जीव बना सकता है। उदाहरण: स्पाइरोगाइरा।
Animated Diagram – Fragmentation in Spirogyra
Important:
Fragmentation is different from regeneration. In fragmentation, breaking of the body directly produces fragments that can grow into new organisms.
Fragmentation is different from regeneration. In fragmentation, breaking of the body directly produces fragments that can grow into new organisms.
9. Regeneration | पुनर्जनन
English:
Regeneration is the ability of an organism to regrow lost or damaged body parts. In some simple organisms, a fragment can develop into a complete organism. Example: Planaria. Planaria has specialised cells that can divide and differentiate to form different cell types. हिन्दी:
पुनर्जनन वह क्षमता है जिसके द्वारा कोई जीव अपने खोए या क्षतिग्रस्त अंगों अथवा शरीर के भागों को पुनः विकसित कर सकता है। कुछ सरल जीवों में शरीर का टुकड़ा पूरा नया जीव भी बना सकता है। उदाहरण: प्लेनेरिया।
Regeneration is the ability of an organism to regrow lost or damaged body parts. In some simple organisms, a fragment can develop into a complete organism. Example: Planaria. Planaria has specialised cells that can divide and differentiate to form different cell types. हिन्दी:
पुनर्जनन वह क्षमता है जिसके द्वारा कोई जीव अपने खोए या क्षतिग्रस्त अंगों अथवा शरीर के भागों को पुनः विकसित कर सकता है। कुछ सरल जीवों में शरीर का टुकड़ा पूरा नया जीव भी बना सकता है। उदाहरण: प्लेनेरिया।
Animated Diagram – Regeneration in Planaria
Very Important Concept:
Regeneration should not always be considered reproduction. If an organism only repairs a damaged body part, it is regeneration but not reproduction. When a separated fragment develops into a complete new organism, regeneration contributes to reproduction.
Regeneration should not always be considered reproduction. If an organism only repairs a damaged body part, it is regeneration but not reproduction. When a separated fragment develops into a complete new organism, regeneration contributes to reproduction.
10. Difference Between Fission, Budding, Fragmentation and Regeneration
| Feature | Fission | Budding | Fragmentation | Regeneration |
|---|---|---|---|---|
| Basic process | Division | Bud formation | Body breaks into fragments | Regrowth of body parts |
| Parent body | Divides | Remains with bud initially | Breaks into fragments | May remain intact |
| Example | Amoeba | Hydra, Yeast | Spirogyra | Planaria |
| New organism | Two or many | From bud | From fragments | From regenerated fragment in some organisms |
11. Binary vs Multiple Fission
| Binary Fission | Multiple Fission |
|---|---|
| Produces two daughter organisms. | Produces many daughter organisms. |
| Amoeba is a common example. | Plasmodium is a common example. |
| Parent divides into two. | Repeated nuclear division produces many nuclei followed by cytoplasmic separation. |
12. Why Can Simple Organisms Reproduce by These Methods?
Simple organisms generally have a relatively simple body organisation.
Their body cells may retain the ability to divide and form different structures.
Therefore, processes such as fragmentation and regeneration can produce complete organisms in some simple organisms.
In complex multicellular organisms, specialised tissues and organs make such whole-body reproduction by fragmentation much less common.
13. Advantages of Asexual Reproduction
- Usually requires only one parent.
- No need for fusion of gametes.
- Generally fast.
- Many offspring can be produced in a relatively short time.
- Useful in stable environments.
14. Limitations of Asexual Reproduction
- Usually produces less variation than sexual reproduction.
- Lower genetic diversity can reduce adaptability to major environmental changes.
- A disease or environmental change affecting one individual may affect many genetically similar offspring.
15. Variation and Survival | विविधता और उत्तरजीविता
Variations arise partly because DNA copying is not perfectly accurate.
Some variations may help organisms survive better under changing environmental conditions.
Over generations, useful variations can become more common in populations through natural selection.
Thus:
DNA Copying → Variation → Natural Selection → Adaptation
16. MCQs – Multiple Choice Questions
Q1. Which organism commonly reproduces by binary fission?
A) Amoeba
B) Hydra
C) Yeast
D) Spirogyra
Answer: A) Amoeba
Amoeba commonly reproduces by binary fission, in which one cell divides into two daughter cells.
Q2. In binary fission, one parent generally forms:
A) One daughter
B) Two daughters
C) Three daughters
D) Many spores
Answer: B) Two daughters
Q3. Multiple fission is associated with:
A) Hydra
B) Yeast
C) Plasmodium
D) Spirogyra
Answer: C) Plasmodium
Q4. Budding is commonly observed in:
A) Amoeba
B) Hydra
C) Spirogyra
D) Plasmodium
Answer: B) Hydra
Q5. Which is a unicellular organism reproducing by budding?
A) Yeast
B) Planaria
C) Hydra
D) Spirogyra
Answer: A) Yeast
Q6. Fragmentation is commonly seen in:
A) Hydra
B) Amoeba
C) Spirogyra
D) Plasmodium
Answer: C) Spirogyra
Q7. Regeneration is well demonstrated by:
A) Planaria
B) Yeast
C) Amoeba
D) Plasmodium
Answer: A) Planaria
Q8. The small outgrowth formed during budding is called:
A) Spore
B) Fragment
C) Bud
D) Gamete
Answer: C) Bud
Q9. Which process involves breaking of the body into pieces?
A) Budding
B) Fragmentation
C) Binary fission
D) Fertilisation
Answer: B) Fragmentation
Q10. Which process is primarily related to regrowth of lost body parts?
A) Regeneration
B) Budding
C) Fission
D) Pollination
Answer: A) Regeneration
Q11. Asexual reproduction generally involves:
A) Two parents
B) One parent
C) Three parents
D) No parent
Answer: B) One parent
Q12. Fusion of gametes is absent in:
A) Asexual reproduction
B) Sexual reproduction
C) Fertilisation
D) Pollination
Answer: A) Asexual reproduction
Q13. The genetic material that is copied before reproduction is:
A) Protein
B) Lipid
C) DNA
D) Starch
Answer: C) DNA
Q14. Small differences produced during DNA copying are called:
A) Variations
B) Buds
C) Spores
D) Tissues
Answer: A) Variations
Q15. Which process is most directly associated with a small outgrowth?
A) Fragmentation
B) Budding
C) Multiple fission
D) Regeneration
Answer: B) Budding
Q16. Which organism is a filamentous alga?
A) Amoeba
B) Hydra
C) Spirogyra
D) Yeast
Answer: C) Spirogyra
Q17. Which statement about regeneration is correct?
A) It always means reproduction.
B) It involves regrowth of lost or damaged parts.
C) It always involves gametes.
D) It occurs only in plants.
Answer: B) It involves regrowth of lost or damaged parts.
Q18. Which method can produce many daughter organisms from one parent?
A) Binary fission
B) Multiple fission
C) Budding
D) Pollination
Answer: B) Multiple fission
Q19. In Amoeba, which division is associated with binary fission?
A) Nuclear division followed by cytoplasmic division
B) Only cell wall formation
C) Only chlorophyll division
D) Gamete fusion
Answer: A) Nuclear division followed by cytoplasmic division
Q20. Which pair is correctly matched?
A) Hydra – Fragmentation
B) Amoeba – Binary fission
C) Spirogyra – Budding
D) Yeast – Multiple fission
Answer: B) Amoeba – Binary fission
Q21. Asexual reproduction usually produces:
A) Less variation than sexual reproduction
B) More variation always
C) No DNA
D) Only gametes
Answer: A) Less variation than sexual reproduction
Q22. Which structure develops during budding?
A) Bud
B) Pollen grain
C) Zygote
D) Seed
Answer: A) Bud
Q23. Which is NOT a method of asexual reproduction discussed here?
A) Binary fission
B) Budding
C) Fragmentation
D) Fertilisation
Answer: D) Fertilisation
Q24. Which organism can reproduce through budding?
A) Hydra
B) Amoeba only
C) Spirogyra only
D) Plasmodium only
Answer: A) Hydra
Q25. The major significance of DNA copying is:
A) Transfer of genetic information
B) Production of digestive juice
C) Production of water
D) Removal of waste
Answer: A) Transfer of genetic information
Q26. A fragment of Spirogyra can:
A) Form a new filament
B) Produce a flower
C) Become a gamete
D) Become a seed
Answer: A) Form a new filament
Q27. Which organism is a unicellular fungus?
A) Yeast
B) Hydra
C) Planaria
D) Spirogyra
Answer: A) Yeast
Q28. Which process may involve repeated nuclear division before cytoplasmic separation?
A) Multiple fission
B) Budding
C) Fragmentation
D) Pollination
Answer: A) Multiple fission
Q29. Variation is important because it can:
A) Contribute to adaptation
B) Stop DNA copying
C) Prevent all reproduction
D) Eliminate heredity
Answer: A) Contribute to adaptation
Q30. Which sequence is correct for budding?
A) Bud formation → growth → possible separation
B) Fertilisation → seed → bud
C) Fragmentation → pollen → zygote
D) Spore → gamete → bud
Answer: A) Bud formation → growth → possible separation
17. Subjective Questions with Answers
2 Marks
Q1. What is binary fission?
Binary fission is an asexual reproduction method in which one parent organism divides into two daughter organisms. Amoeba is a common example.
2 Marks
Q2. Define budding with one example.
Budding is asexual reproduction in which a small outgrowth or bud develops on the parent body. Example: Hydra or Yeast.
2 Marks
Q3. What is fragmentation?
Fragmentation is the breaking of the body of an organism into two or more fragments, each of which can grow into a new organism in suitable organisms. Example: Spirogyra.
2 Marks
Q4. What is regeneration?
Regeneration is the ability of an organism to regrow lost or damaged body parts. In some organisms, a fragment may develop into a complete new organism.
2 Marks
Q5. Name the organism associated with multiple fission.
Plasmodium is a common example of an organism showing multiple fission.
3 Marks
Q6. Explain binary fission in Amoeba.
The nucleus of Amoeba divides first. The cytoplasm then divides, resulting in two daughter Amoebae. Each daughter receives genetic material.
3 Marks
Q7. Explain budding in Hydra.
A small outgrowth develops on the body of Hydra. It grows due to cell division and develops structures similar to the parent. The mature bud may detach and live independently.
3 Marks
Q8. Explain fragmentation in Spirogyra.
The filament of Spirogyra may break into smaller fragments. Under suitable conditions, each fragment grows and develops into a complete Spirogyra filament.
3 Marks
Q9. Why is regeneration not always considered reproduction?
Regeneration may only repair a damaged or lost body part. In that case no new individual is produced. It contributes to reproduction only when a separated fragment develops into a complete new organism.
3 Marks
Q10. What is the role of DNA copying in reproduction?
DNA copying transfers genetic information to offspring. Because copying is not perfectly accurate, small variations may also arise.
4 Marks
Q11. Differentiate between binary and multiple fission.
Binary fission:
- One parent divides into two daughter organisms.
- Example: Amoeba.
- One parent produces many daughter organisms.
- Example: Plasmodium.
4 Marks
Q12. Explain budding in Yeast.
A small bud develops on the yeast cell. The nucleus divides and one daughter nucleus enters the bud. The bud grows and may eventually separate from the parent to form an independent yeast cell.
4 Marks
Q13. Differentiate between fragmentation and budding.
| Fragmentation | Budding |
|---|---|
| Body breaks into fragments. | A small outgrowth develops. |
| Example: Spirogyra. | Examples: Hydra, Yeast. |
4 Marks
Q14. Explain why asexual reproduction is generally faster than sexual reproduction.
Asexual reproduction usually requires only one parent and does not require production and fusion of two types of gametes. Therefore, in many organisms it can occur rapidly and produce offspring in a short time.
4 Marks
Q15. Explain the relationship between DNA copying and variation.
DNA copying is necessary for transferring genetic information. The copying process is not perfectly accurate, so small changes can occur. These changes produce variations among offspring.
5 Marks
Q16. Describe the process of binary fission in Amoeba with a labelled diagram.
First, the nucleus divides into two. The cytoplasm then constricts and separates. Finally, two daughter Amoebae are formed. Each daughter receives genetic material.
5 Marks
Q17. Describe budding in Hydra.
A small bud appears on the body of Hydra. Repeated cell division increases its size. The bud develops structures similar to the parent. When mature, it may detach and become an independent Hydra.
5 Marks
Q18. Explain fragmentation and regeneration with examples.
Fragmentation involves breaking of the organism into pieces, as seen in Spirogyra. Regeneration involves regrowth of lost or damaged parts and can produce complete organisms from fragments in organisms such as Planaria.
5 Marks
Q19. Discuss two advantages and two limitations of asexual reproduction.
Advantages:
- Usually requires one parent.
- Can occur rapidly.
- Usually produces less variation.
- Lower variation may reduce adaptability to major environmental changes.
5 Marks
Q20. Explain the importance of variations in organisms.
Variations create differences among organisms of the same species. Some variations may provide an advantage in changing environments. Over generations, advantageous variations may become more common through natural selection.
6 Marks
Q21. Explain four major methods of asexual reproduction discussed in this topic.
1. Fission: Parent divides into two or many daughter organisms. Example: Amoeba, Plasmodium.
2. Budding: A bud develops on the parent and grows into a new organism. Example: Hydra, Yeast.
3. Fragmentation: Body breaks into fragments and suitable fragments develop into new organisms. Example: Spirogyra.
4. Regeneration: Lost or damaged parts regrow; in some simple organisms fragments can form complete organisms. Example: Planaria.
2. Budding: A bud develops on the parent and grows into a new organism. Example: Hydra, Yeast.
3. Fragmentation: Body breaks into fragments and suitable fragments develop into new organisms. Example: Spirogyra.
4. Regeneration: Lost or damaged parts regrow; in some simple organisms fragments can form complete organisms. Example: Planaria.
6 Marks
Q22. Compare fission, budding, fragmentation and regeneration.
| Method | Main Feature | Example |
|---|---|---|
| Fission | Parent divides | Amoeba |
| Budding | Bud develops | Hydra |
| Fragmentation | Body breaks into fragments | Spirogyra |
| Regeneration | Lost parts regrow | Planaria |
6 Marks
Q23. Explain asexual reproduction and discuss its advantages and disadvantages.
Asexual reproduction generally involves one parent and no fusion of gametes.
Advantages:
- Fast reproduction.
- One parent is sufficient.
- Many offspring may be produced quickly.
- Generally produces less variation.
- Population may be vulnerable to environmental changes.
6 Marks
Q24. Explain how DNA copying is related to heredity and variation.
DNA contains genetic information. During reproduction, DNA is copied and transferred to the new organism. The copying process is not completely accurate, so small differences may arise. These differences are called variations. Variations can influence survival and adaptation.
6 Marks
Q25. Explain the difference between regeneration and reproduction.
Regeneration: Regrowth of lost or damaged body parts.
Reproduction: Formation of a new individual.
Regeneration may occur without formation of a new organism, such as repair of a damaged body part. However, in some simple organisms, a separated fragment can regenerate into a complete new organism, thereby contributing to reproduction.
6 Marks
Q26. A student says that fragmentation and regeneration are exactly the same process. Is the statement correct?
No. Fragmentation refers to breaking of the body into pieces. Regeneration refers to regrowth and formation of lost or missing structures. In some organisms, fragmentation is followed by regeneration, resulting in new individuals.
6 Marks
Q27. Why is asexual reproduction useful for organisms living in stable environments?
In a stable environment, offspring similar to the parent are likely to remain well adapted. Asexual reproduction is also generally rapid and requires only one parent. Therefore, a favourable set of characteristics can be reproduced efficiently.
6 Marks
Q28. Explain the importance of specialised cells in regeneration.
Some organisms contain cells capable of dividing and differentiating into different cell types. These cells help rebuild tissues and organs. In organisms such as Planaria, such regenerative ability is especially developed.
6 Marks
Q29. Why does asexual reproduction generally produce less variation than sexual reproduction?
Asexual reproduction usually involves one parent and does not involve fusion of genetic material from two parents. Therefore, offspring generally inherit a genetic makeup very similar to the parent, apart from variations caused by DNA-copying differences. Sexual reproduction combines genetic material from two parents and generally produces greater variation.
6 Marks
Q30. Describe the complete concept flow of fission, budding, fragmentation and regeneration.
DNA Copying
These are different ways by which organisms can reproduce or restore body structures. Their common feature is that they do not require fusion of male and female gametes.
→
Asexual Reproduction
→
Fission
→
Budding
→
Fragmentation
→
Regeneration
18. HOTS / Competency Based Questions
HOTS 1.
A student observes that a unicellular organism divides into two nearly equal daughter cells.
Which method is most likely occurring?
Answer: Binary fission.
HOTS 2.
An organism develops a small outgrowth that remains attached to its body for some time before separating.
Identify the method.
Answer: Budding.
HOTS 3.
A filamentous organism breaks into several pieces and each piece grows into a complete filament.
Identify the process and organism.
Answer: Fragmentation in Spirogyra.
HOTS 4.
A scientist cuts a Planarian into pieces and observes that the pieces develop missing structures. Which biological ability is responsible?
Answer: Regeneration.
HOTS 5.
Why can excessive dependence on asexual reproduction be disadvantageous when the environment changes suddenly?
Because asexual reproduction generally produces less variation. A sudden environmental change may therefore affect many similar individuals.
19. Important Diagram Labelling
Diagram 1 – Amoeba Binary Fission
- Parent Amoeba
- Nucleus
- Dividing nucleus
- Cytoplasm
- Daughter Amoebae
- Parent Hydra
- Bud
- Tentacles
- Nucleus
- Filament
- Fragment
- New filament
- Parent Planaria
- Fragment
- Regenerating region
- New organism
20. CBSE Golden Points | परीक्षा के लिए महत्वपूर्ण बिंदु
- Fission = division of parent organism.
- Binary fission produces two daughter organisms.
- Amoeba → Binary fission.
- Multiple fission produces many daughter organisms.
- Plasmodium → Multiple fission.
- Budding involves a small outgrowth called bud.
- Hydra and Yeast → Budding.
- Fragmentation → Spirogyra.
- Regeneration → Planaria.
- DNA copying is necessary for reproduction.
- DNA copying can produce small variations.
- Asexual reproduction generally involves one parent.
- Asexual reproduction does not involve fusion of gametes.
- Regeneration is not always reproduction.
- Variation is important for adaptation and evolution.
🧠 Memory Trick: F-B-F-R
F → Fission → Amoeba
B → Budding → Hydra / Yeast
F → Fragmentation → Spirogyra
R → Regeneration → Planaria
F → Fission → Amoeba
B → Budding → Hydra / Yeast
F → Fragmentation → Spirogyra
R → Regeneration → Planaria
21. One-Line Revision | एक पंक्ति में पुनरावृत्ति
Fission: Parent divides → new organisms.
Budding: Bud grows → new organism.
Fragmentation: Body breaks → fragments grow.
Regeneration: Lost parts regrow → sometimes complete organism.
Final Concept:
Budding: Bud grows → new organism.
Fragmentation: Body breaks → fragments grow.
Regeneration: Lost parts regrow → sometimes complete organism.
Final Concept:
Asexual Reproduction → One Parent → No Gamete Fusion → DNA Copying → New Individual + Possible Variation
22. Complete Chapter Flow
Asexual Reproduction
→
Fission
→
Budding
→
Fragmentation
→
Regeneration
Exam Tip:
For a 3–5 mark CBSE answer, always write: Definition + Process/Steps + Example + Diagram (where applicable). For example: Amoeba → Binary Fission
Hydra/Yeast → Budding
Spirogyra → Fragmentation
Planaria → Regeneration
For a 3–5 mark CBSE answer, always write: Definition + Process/Steps + Example + Diagram (where applicable). For example: Amoeba → Binary Fission
Hydra/Yeast → Budding
Spirogyra → Fragmentation
Planaria → Regeneration
