Discuss reliance on pollinators for self and cross routes
Compare reproductive opportunities while recognising wind transfer and species differences.
Exam scope and assessment notes
Extended only (Supplement) · Biology 0970, 2026–2028. Use the stated specimen features and evidence. Diagrams are schematic. Written practice is self-checked; human subject-teacher review, supervised practical competence and cumulative assessment remain pending. Cambridge states that IGCSE 0970 has the same subject content as IGCSE 0610, with 9–1 grading. This StudyForA pathway maps the 2026–2028 syllabus only. This 9–1 graded qualification is available only in a limited number of administrative zones. Confirm that your centre can enter you for this code and exam series with Cambridge International. Cambridge has published a separate syllabus for 2029. StudyForA has not reconciled that version yet; this page supports exams in 2026, 2027 and 2028 only.
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
What can selfing reduce reliance on?
What you will learn
- Distinguish same-plant opportunity from a no-carrier guarantee
- Explain cross-transfer dependence in the stated species
Discuss reliance on pollinators for self and cross routes
| Feature | Meaning |
|---|---|
| Self potential | Opportunity without another suitable plant |
| Self limit | A carrier and suitable later conditions may still be needed |
| Animal cross | Between-plant animal transfer opportunity |
| Wind cross | Between-plant air carriage opportunity |
Distinguish same-plant opportunity from a no-carrier guarantee
Self-pollination can reduce reliance on finding a different suitable plant because the pollen origin and destination are on the same plant. In a species that permits the route, this can provide a reproductive opportunity when other plants or transfer opportunities are scarce. It does not eliminate the need for suitable reproductive conditions or guarantee later successful fertilisation.
Self-pollination also does not universally mean no carrier is involved. Pollen may move within or between flowers of one plant with help from an insect or air movement, depending on flower structure and species. Separate the need for another plant from the need for the transfer mechanism in the stated case; these are different dependencies.
Explain cross-transfer dependence in the stated species
Cross-pollination requires transfer to a different same-species plant. In an insect-pollinated species, that route may rely on a suitable animal pollinator moving grains between plants. In a wind-pollinated species it relies on air carriage instead of an animal visit. Availability, distance, flowering timing and compatibility can affect opportunities, so a nearby plant alone does not prove successful reproduction.
Discuss reliance using the supplied species context. Selfing may provide reproductive assurance with fewer between-plant opportunities, while crossing can depend more on a successful external between-plant route. Balance this potential assurance with the possible limits on genetic mixing. Neither route guarantees an offspring, and neither definition states that every species uses insects.
Pause and explain
What carries pollen in the supplied wind-cross route?
Worked example
Does self-pollination universally require no insect or wind movement?
Show the worked solution
- The definition specifies same-plant identity.
- The actual carrier depends on the species and flower arrangement.
Answer No; same-plant transfer may still involve a carrier.
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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.
Explain one possible reproductive-assurance advantage of self-pollination.
Give me a hint
Use the same-plant opportunity without guaranteeing fusion.
Compare my reasoning
- A second pollen-source plant is not required.
- A permitted same-plant route can provide an opportunity when other plants are scarce.
Where the species permits successful selfing, pollen from the same plant can provide a reproductive opportunity without another suitable plant; later success is not guaranteed.
Look for these in your work
- Explain the reduced partner dependence
- Retain species and success limits
Compare reliance in an insect-cross route with a wind-cross route.
Give me a hint
Both cross plants, but their carriers differ.
Compare my reasoning
- Insect-cross depends on suitable between-plant animal transfer.
- Wind-cross depends on air carriage between plants.
Both need anther-to-stigma transfer to a different same-species plant; one uses an insect carrier, while the other uses wind.
Look for these in your work
- Keep the cross definition
- Distinguish the carrier dependence
Correct “self-pollination always occurs without carriers and cross-pollination always needs insects.”
Give me a hint
Route identity and carrier are separate facts.
Compare my reasoning
- Self-transfer can involve a carrier.
- Cross-transfer can use wind or animals according to species.
Self describes same-plant transfer and may involve a carrier. Cross describes transfer between same-species plants and may use wind or animals; no universal insect rule follows.
Look for these in your work
- Correct both absolute claims
- Separate plant identity from transfer mechanism
Common mistakes
- Equating no second plant with no pollen-transfer mechanism.
- Calling every cross route insect-dependent.
What can you explain now?
What carries pollen in the supplied wind-cross route?
Compare with the explanation
Air movement between plants
An animal visitor is not required for this stated mechanism.
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Make it stick
Compare reliance on transfer opportunities without treating every route as insect-dependent.
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.