Exercise Solutions Available
Step-by-step answers for all textbook questions in this chapter
Quick Summary
Reproduction is the biological process by which organisms produce new individuals. Asexual reproduction is fast and uses one parent; sexual reproduction involves gametes, fertilisation, and genetic variation.
Asexual Reproduction
Main features:
- One parent
- No gamete fusion
- Offspring are usually genetically similar
- Common in simple organisms
Examples:
- Binary fission in Amoeba
- Budding in Hydra
- Fragmentation in some lower organisms
- Regeneration in Planaria
Sexual Reproduction
Main features:
- Formation of male and female gametes
- Fertilisation produces zygote
- Offspring show variation
- Important for evolution
Stages in Sexual Reproduction
1. Pre-fertilisation events 2. Fertilisation 3. Post-fertilisation events
Important Terms
- Juvenile phase
- Reproductive phase
- Senescent phase
- Gametogenesis
- Fertilisation
- Embryogenesis
Asexual vs Sexual Reproduction
| Asexual Reproduction | Sexual Reproduction |
|---|---|
| One parent | Usually two parents |
| No gamete fusion | Gamete fusion present |
| Little variation | Produces variation |
| Faster process | Comparatively slower |
Important Questions
One Mark
1. Define reproduction. 2. Name one organism that reproduces by budding. 3. What is fertilisation?
Short Answer
1. Distinguish between asexual and sexual reproduction. 2. Explain the phases in an organism's life cycle. 3. Write short notes on binary fission and budding.
Long Answer
1. Explain the stages in sexual reproduction. 2. Compare asexual and sexual reproduction. 3. Explain why sexual reproduction is important in evolution.
Common Mistakes
- Writing that all offspring from reproduction are identical.
- Confusing fertilisation with gamete formation.
- Forgetting variation when explaining sexual reproduction.
- Listing examples without linking them to the mode of reproduction.
Revision Checklist
- [ ] Asexual reproduction examples
- [ ] Sexual reproduction stages
- [ ] Life-cycle phases
- [ ] Key terms
- [ ] Comparison table