CIE iGCSE Co-ordinated Sciences-B15.1 Asexual reproduction- Study Notes- New Syllabus
CIE iGCSE Co-ordinated Sciences-B15.1 Asexual reproduction – Study Notes
CIE iGCSE Co-ordinated Sciences-B15.1 Asexual reproduction – Study Notes -CIE iGCSE Co-ordinated Sciences – per latest Syllabus.
Key Concepts:
Core
Describe asexual reproduction as a process resulting in the production of genetically identical offspring from one parent
Identify examples of asexual reproduction in diagrams, images and information provided
Supplement
Discuss the advantages and disadvantages of asexual reproduction to a population of a species in the wild
CIE iGCSE Co-Ordinated Sciences-Concise Summary Notes- All Topics
Asexual Reproduction
📌 Definition
Asexual reproduction is a process resulting in the production of genetically identical offspring from one parent.
🌱 Key Features
- Only one parent involved.
- No gametes or fertilisation.
- Offspring are clones (genetically identical to parent).
- Involves mitosis (cell division producing identical cells).
- Common in plants, bacteria, fungi, some simple animals.
🌿 Examples
- Bacteria → binary fission (splitting in two).
- Plants → runners in strawberry plants, bulbs in onions, tubers in potatoes.
- Yeast → budding.
📊 Summary Table
| Feature | Asexual reproduction |
|---|---|
| Parents | One |
| Gametes | Not involved |
| Variation | None (offspring identical) |
| Cell division | Mitosis |
| Examples | Bacteria, fungi, plants |
⚡ Quick Recap
One parent → clones → no variation.
Mitosis-based.
Examples: bacteria (fission), yeast (budding), plants (runners, bulbs).
Memory tip: “Asexual = Alone parent, All same.”
Examples of Asexual Reproduction
📌 Introduction
Asexual reproduction happens in many organisms, producing genetically identical offspring. In exams, you should be able to spot and label these examples in diagrams/images.
🌿 Key Examples to Identify
- Binary Fission (Bacteria)
Parent cell splits into two identical cells.
Seen in bacteria and protozoa (e.g. Amoeba). - Budding (Yeast, Hydra)
A small outgrowth (bud) forms on the parent.
Bud grows and may detach to live independently. - Vegetative Propagation (Plants)
New plants grow from non-reproductive parts (stems, roots, leaves).
Examples:
Strawberry plants → runners (long horizontal stems).
Potatoes → tubers (underground storage organs).
Onions → bulbs. - Spore Formation (Fungi)
Fungi like moulds produce spores that grow into new identical individuals.
📊 Summary Table
| Organism | Method | Diagram Feature |
|---|---|---|
| Bacteria | Binary fission | Cell dividing into 2 |
| Yeast | Budding | Small bud on parent cell |
| Strawberry | Runner | Horizontal stem with new plant |
| Potato | Tuber | Underground swollen stem |
| Onion | Bulb | Layers with new shoot |
| Fungi (moulds) | Spores | Spore cases releasing spores |
⚡ Quick Recap
Bacteria → fission
Yeast/Hydra → budding
Plants → runners, tubers, bulbs
Fungi → spores
All offspring = clones (no variation)
Memory tip: “FAB Plants” = Fission, Asexual budding, Bulbs/tubers/runners, Plants.
Asexual Reproduction in the Wild
📌 Introduction
Asexual reproduction produces genetically identical offspring from a single parent. In natural populations, this has both benefits and risks.
✅ Advantages (to the species)
- Rapid population growth
No need for mate → quick reproduction.
Useful when conditions are stable and resources are plentiful. - Energy-efficient
No energy wasted in finding mates or producing gametes. - Successful traits passed on directly
If the parent is well adapted to the environment, all offspring will be equally adapted. - Colonisation
A single organism can establish a new population in a new area (e.g. plants from runners or tubers).
❌ Disadvantages (to the species)
- No genetic variation
Offspring are clones → all equally vulnerable to diseases, parasites, and predators. - Poor adaptability
If the environment changes (climate, food source, introduction of predators), the whole population may be wiped out. - Competition
Since all offspring are identical and stay near the parent, they may compete strongly for the same resources.
📊 Summary Table
| Advantage | Disadvantage |
|---|---|
| Fast population increase | No variation → disease can wipe all out |
| No need for mates | Poor adaptability to change |
| Energy-saving | Offspring compete for same resources |
| Keeps successful traits | If environment changes, traits may not help |
⚡ Quick Recap
Good when stable: fast, efficient, reliable.
Bad when changing: no variation, vulnerable.
Memory tip: “Asexual = Always Same → Safe in stability, Risky in change.”