IGCSE Biology / Reproduction in plants
Insect and wind pollination
Edexcel International GCSE Biology (4BI1), chapter 13: Reproduction in plants, specification point 3.3. Free lesson.
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Pollination is the transfer of pollen from an anther to a stigma. Flower features differ depending on whether insects or wind carry the pollen.
What pollination means
Pollination happens when pollen moves from an anther to a stigma. It is not the same as fertilisation, which happens afterwards when nuclei fuse. The pollen carrier may be an insect or the wind.
How insect-pollinated flowers attract insects
An insect-pollinated flower attracts an insect, rewards it, then places pollen where it can be carried to another flower. Its features help pollen stick to the insect and reach a stigma. Large, brightly coloured petals attract insects from a distance. Nectaries produce sugary nectar as a reward. As an insect reaches it, it brushes past the anthers. Scent attracts insects, including at night. The anthers are inside the flower, positioned so an insect brushes against them. The stigma is also inside and is sticky, so pollen carried by an insect can rub off onto it.…
How wind-pollinated flowers expose their pollen
Wind-pollinated flowers do not need to attract or reward an animal. Instead, their reproductive parts are exposed so pollen can be released into the air and caught by another flower. Petals are small and dull, or absent, because there is nothing to attract. There are no nectaries or scent because no animal needs a reward. The anthers hang outside on loose attachments. Wind shakes pollen out of them. A large, feathery stigma hangs outside, giving it a large surface to catch pollen from the air. Wind-pollinated pollen is small, light and smooth, so it can travel through the air.…
How the pollen carrier explains the differences
Each flower type is suited to its carrier. Insect-pollinated flowers bring insects into contact with pollen, while wind-pollinated flowers release pollen and provide a large surface to catch it. Insect-pollinated: large, bright petals; nectar and scent; anthers and stigma inside; small amounts of large, sticky or spiky pollen. Wind-pollinated: small, dull or absent petals; no nectar or scent; anthers and stigma outside; huge amounts of small, light and smooth pollen.