Adaptations for Pollination

Section 1 of 7Flower structure and function

Part	Function
Sepal	Covers and protects the flower while it is still a bud
Petal	Often brightly coloured to attract insects
Anther	Makes and releases pollen grains, which contain the male gametes
Filament	Holds the anther up in position
Stigma	Sticky surface at the top of the female part that catches pollen
Style	Tube that connects the stigma to the ovary
Ovary	Contains the ovules
Ovule	Contains the female gamete (egg cell); it becomes a seed after fertilisation

Section 2 of 7What pollination means

Definition

• Definition Pollination is the transfer of pollen from an anther to a stigma.
  • It brings the male and female gametes of a plant close enough to allow fertilisation later.

Carriers of pollen

• Carriers of pollen Pollen is carried either by animals, usually insects, or by the wind.
  • The flower's structure reflects which of these it relies on.

Section 3 of 7How an insect pollinates

1Insect is attracted

• Insect is attracted Bright petals, scent and the promise of nectar bring an insect to the flower.

2Pollen is picked up

• Pollen is picked up The insect pushes past the anthers to reach the nectar and the sticky pollen rubs onto its body.

3Insect moves on

• Insect moves on It visits another flower of the same type.

4Pollen is deposited

• Pollen is deposited Its body brushes the sticky stigma, which collects some of the pollen grains.

Section 4 of 7Comparing the two types of flower

Feature	Insect-pollinated	Wind-pollinated
Petals	Large, brightly coloured to attract insects	Small and dull, often green or brown, because showy petals would waste energy
Scent and nectar	Produced to draw insects in	Not produced
Anthers	Stiff filaments hold them inside the flower where insects brush against them	Hang outside the flower on long filaments so the wind can blow pollen away
Stigma	Sticky and inside the flower to catch pollen from insects' bodies	Large and feathery, hanging outside to filter pollen from the air
Pollen grains	Fewer, sticky or spiky so they cling to insects	Very many, light and smooth so they travel far on air currents

Section 5 of 7Linking structure to function

Adaptation to the pollinator

Insect flowers

• Insect flowers Every feature increases the chance of contact with a visiting insect.

Wind flowers

• Wind flowers Every feature exposes the anthers and stigmas to moving air, and energy is not spent on petals or nectar.

Exam approach

• Exam approach Name the feature, then say how it helps pollen be released, carried or caught.

Section 6 of 7Key terms

Term	Meaning
Pollination	The transfer of pollen from an anther to a stigma.
Anther	The part of the stamen that produces pollen.
Stigma	The sticky surface that collects pollen grains.
Nectar	A sugary liquid made by flowers to reward visiting insects.
Ovule	A structure in the ovary containing the female gamete.
Filament	The stalk that supports an anther.

Section 7 of 7Exam technique

1

Describing a wind-pollinated flower as having bright petals or nectar. These are features of insect-pollinated flowers.

2

Saying the stigma makes pollen. The anther makes pollen; the stigma only collects it.

3

Stating that the feature is adapted without explaining how, for example 'feathery stigma' needs 'to catch airborne pollen'.

4

Mixing up the male parts (anther and filament) with the female parts (stigma, style and ovary).