Define self-pollination using the identity of the plant
Recognise both transfer within one flower and transfer between flowers on the same plant.
Cross-referenced to the 2028–2029 0653 section using original teaching from the related single-science courses. A 0653-specific objective-by-objective and Core/Supplement review is in progress. Written practice is self-checked and does not demonstrate supervised laboratory competence or award an official Cambridge grade.
Before you begin
- Recall gametes, nuclear fusion, cellular respiration and the distinction between reproduction and growth.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
Which route is self-pollination?
What you will learn
- Track the plant identity rather than only flower labels
- Keep pollen transfer separate from fertilisation
Define self-pollination using the identity of the plant
| Feature | Meaning |
|---|---|
| Within a flower | Anther to stigma of the same flower |
| Between flowers | Different flowers on the same plant |
| Decisive identity | Same plant |
| Separate event | Successful self-fertilisation requires later fusion |
Track the plant identity rather than only flower labels
Self-pollination is transfer of pollen grains from an anther to a stigma of the same flower, or to a stigma of another flower on the same plant. The plant identity is decisive. The two flowers may look separated in a diagram, but if both belong to plant A, the route remains self-pollination rather than cross-pollination.
The original labelled model uses flower A1 and flower A2 on plant A, with flower B1 on a separate plant B. A1 → A1 and A1 → A2 are both self-pollination routes, provided the arrows mean anther-to-stigma pollen transfer. The names do not themselves establish an event unless the arrow material and endpoints are specified.
Keep pollen transfer separate from fertilisation
Self-pollination is not the same as asexual reproduction. It transfers pollen in a sexual reproductive pathway, and successful later self-fertilisation still involves fusion of reproductive nuclei. Nor does self-pollination automatically prove self-fertilisation: receptive and compatible conditions and the later internal route must still permit fusion.
Some species have mechanisms that prevent or reduce successful self-fertilisation, while others permit it. The definition does not claim every plant can self-fertilise or that self-pollination always occurs without insects or wind. Classify the stated transfer by the origin and destination plant, then keep compatibility and subsequent fusion as separate questions.
Sources for this lesson
Pause and explain
Does self-pollination by itself prove nuclear fusion?
Worked example
Pollen travels from flower A1 to flower A2 on the same plant A. Classify the route.
Show the worked solution
- Two flowers can belong to one plant.
- The plant identity matches.
Answer Self-pollination.
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Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.
Test this topic →From guided practice to a new situation
Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
Define self-pollination including both allowed flower routes.
Give me a hint
Use the same-plant condition.
Compare my reasoning
- Transfer can occur within one flower.
- It can also occur between different flowers on the same plant.
Anther-to-stigma transfer of pollen within the same flower or between flowers of the same plant.
Look for these in your work
- Include both routes
- Keep the same-plant condition
Classify A1 → A1 and A1 → A2 when both flowers are on plant A and arrows show anther-to-stigma pollen transfer.
Give me a hint
Count plants, not simply flower names.
Compare my reasoning
- The first stays within one flower.
- The second changes flower but not plant.
Both are self-pollination.
Look for these in your work
- Classify both routes
- Explain that plant identity is unchanged
Correct “self-pollination is cloning and must happen without any carrier.”
Give me a hint
Separate sexual transfer from copying and the carrier question.
Compare my reasoning
- Successful later fusion is part of sexual reproduction.
- The definition identifies the plant relationship, not the carrier.
Self-pollination is pollen transfer on the same plant, not asexual cloning. It may involve a carrier, and it does not alone prove successful self-fertilisation.
Look for these in your work
- Correct the reproduction distinction
- Avoid the no-carrier guarantee
Common mistakes
- Calling transfer between any two flowers cross-pollination.
- Equating self-pollination with cloning or proven fusion.
What can you explain now?
Does self-pollination by itself prove nuclear fusion?
Compare with the explanation
No; transfer and fertilisation are separate
The internal event needs additional evidence.
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Make it stick
Define self-pollination by same-plant identity, including different flowers on that plant.
If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.