Lesson plan

Flower pollination by insects

Summary
Explore how flowers attract insects by their colours, patterns, smells and pollen. Learn how pollination is two intersecting life cycles.
Science content
Biology: Features, Adaptations of Living Things (K, 1, 3, 7)
Biology: Life Cycles (2)
Biology: Sensing, Organ Systems (4, 5, 6)
Materials
  • materials listed in the activities plus scented flowers
Procedure

Many ways to include a selection of these activities in a lesson on pollination.

If the lesson is outdoors, allow students to explore a flower garden, noticing the colours and smells of the flowers, and the animals visiting them.
If indoors, start discussion on past experiences around flowers.
Ask students what animals they have seen visiting flowers, and lead discussion on what the animals are doing: they are "pollinators." (e.g. bees, flies, beetles, birds)
Pollinators enable the flower to make seeds (by moving pollen from one flower to another), so are part of the life cycle of flowers.
This lesson explores how flowers attract pollinators.

Ask students for ideas on how the flowers attract pollinators.
Write up their ideas, and add more: smell, colour, shape, pollen, nectar.
Then do the following activities that address each of these attractants in turn.

Pollen attracts pollinators:
Collecting pollen activity

Nectar guides show the way to the nectar:
Look at nectar guides on a real flower
Optional: students can make their own symmetrical nectar guide patterns with the Mirror symmetry patterns activity.
Pull apart a flower to show where the nectar guides lead to at the base of the flower, and the nectaries if possible.

Flower colour attracts pollinators:
Flower colours activity
Show the molecular models to older students
Optional: bees see colours that we can't see (ultra violet) and some flowers have UV patterns to guide bees.

Smell attracts pollinators:
Pass around flowers with different smells e.g. rose and clover, and discuss how they smell different, and how different pollinators are attracted by different smells.
Or Insects and flowers matching game with collected flowers or with flowers in a garden, to show how colour and smell attract different pollinators.

Recap while dissecting a flower and apple to show the parts discussed:
Flowers use colour and smell to attract pollinators to the flower.
They use nectar guides and pollen colour to lead them deep inside the flower to the nectar (while brushing past the anthers and picking up pollen).
On the next flower they might leave some of that pollen on the stigma.
Flowers want to get as many insects in and out as possible so as much pollen is transferred between flowers as possible.
When pollen sticks to the stigma, a pollen tube extends down into the ovary, and fertilizes the eggs in there.
The ovary swells and the fertilized eggs make seeds. The petals fall off.
[Show apple] An apple is the ovary of a fertilized flower, and here are the seeds.
The seeds are transported away from the parent plant by different ways - they are eaten by animals with the fruit, they stick onto their fur, are blown by wind or carried by water.
Flowers and pollinators help each other out. The flower gets pollinated. The pollinator gets nectar and pollen.

The posting game, to insert at any point in the lesson, is an active activity to link pollinators and other animals with different flowers.

Notes

Flower colours good to end with as students can spend as long as you need on this activity.

Grades taught
Gr K
Gr 1
Gr 2
Gr 3
Gr 4