Explain the term “Regeneration” as used in relation to reproduction of organisms. Describe briefly how regeneration is carried out in multicellular organisms like Hydra.
Explain the term “Regeneration” as used in relation to reproduction of organisms. Describe briefly how regeneration is carried out in multicellular organisms like Hydra.
Regeneration
Regeneration is the ability of a fully differentiated organism to give rise to a complete new individual from its body parts. If the individual is somehow cut or broken up into many pieces, many of these pieces can grow into separate, complete individuals.
How Regeneration is Carried Out in Multicellular Organisms (like Hydra)
- Specialised Cells: Regeneration is carried out by highly specialised cells present in the organism.
- Proliferation: When the organism is cut, these specialised cells proliferate rapidly, making a large mass of cells.
- Differentiation and Development: From this mass of cells, different cells undergo changes to become various cell types and tissues. These changes occur in an organised sequence referred to as development, ultimately forming a complete new organism.
Marking Scheme
- 1Definition of Regeneration (ability to grow a new organism from cut body parts) (1 mark)
- 2Role of specialised cells and their rapid proliferation into a mass of cells (1 mark)
- 3Explanation of differentiation/development of these cells into various tissues and organs (1 mark)
Hint
Recall how specialized cells multiply and undergo an organized sequence of changes (development) to form tissues and organs.
Quick Oral Answer
Regeneration is the growth of a complete organism from its cut body parts. In Hydra, it is carried out by specialised cells that multiply rapidly and differentiate into various tissues in an organised sequence called development.
Analysis & Explanation
Regeneration is a fascinating process found in simple multicellular organisms like Hydra and Planaria. It relies on specialized regenerative cells that have the potential to multiply and differentiate. However, regeneration is not the same as reproduction because most organisms do not normally depend on being cut up to reproduce; it is primarily a mechanism of repair and accidental recovery that can lead to new individuals.
Common Mistakes
- 1Stating that regeneration is the primary mode of reproduction for complex organisms.
- 2Confusing regeneration with simple fragmentation (fragmentation occurs spontaneously upon maturation, whereas regeneration typically happens after accidental injury/cutting).
Interesting Facts
If you cut a single Planaria or Hydra into several pieces, each piece can grow back into a fully functional, complete individual within days!
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Frequently Asked Questions
How many marks does this question carry in CBSE Class 10 Science 2016?
This question carries 3 marks in the CBSE Class 10 Science 2016 examination.
Which chapter does this question come from in Science?
This question is from the chapter "How do Organisms Reproduce?" in the CBSE Class 10 Science syllabus.
What topic does this question cover in Science?
This question covers the topic "Asexual Reproduction - Regeneration" from CBSE Class 10 Science.
Has this question appeared in other CBSE Science papers?
Yes, a similar question appeared in the 2016 CBSE Class 10 Science paper.
What type of question is this in the CBSE Class 10 Science 2016 paper?
This is a Short Answer question from Section A in the CBSE Class 10 Science 2016 paper.