Self-pollination and cross-pollinationSpec 16.3.9, 16.3.10, 16.3.11
In short
Self-pollination is the transfer of pollen grains from an anther to the stigma of the same flower or another flower on the same plant. Cross-pollination transfers pollen to a flower on a different plant of the same species. Cross-pollination gives more variation, so a population can respond better to change, but it relies more on pollinators.
- Self-pollination
- The transfer of pollen grains from the anther of a flower to the stigma of the same flower or a different flower on the same plant.
- Cross-pollination
- The transfer of pollen grains from the anther of a flower to the stigma of a flower on a different plant of the same species.
In self-pollination only one plant is involved. In cross-pollination two plants of the same species are involved, so the offspring have genetic information from two different parents and show more variation.
Effects on a population
| Self-pollination | Cross-pollination | |
|---|---|---|
| Variation | Less variation in the offspring, because the genetic information comes from one parent plant | More variation in the offspring, because genetic information is mixed from two different plants |
| Capacity to respond to changes in the environment | Less able to respond. The offspring are similar, so a change such as a new disease may affect all of them. Fewer individuals may survive. | Better able to respond. Some varied offspring may be suited to the new conditions, survive and reproduce, so the population is more likely to survive. |
| Reliance on pollinators | Less reliant on pollinators: pollen only has to reach a stigma on the same plant (often in the same flower), so seeds can still be made if pollinators are scarce | Relies on pollinators such as insects, or on the wind, to carry pollen to a different plant. If pollinators are scarce, fewer seeds may be made. |
'Discuss' questions need a benefit and a drawback each time. Link each to variation, to ability to cope with a changing environment, or to reliance on pollinators.
Written and checked against the Cambridge IGCSE Biology (0610) specification · Updated October 2026