🌸 Mystery to solve

Plants can't walk, talk, or hug… so how do they have babies?

Animals can walk over to find a mate. Plants are stuck in the soil! Yet every apple, every sunflower seed, and every coconut proves that plants DO make new plants.

By the end of this lesson, you will know the secret journey a flower goes on — from a speck of pollen to a brand-new seed.

🌻 Warm-up: make a prediction

🎯 Learning objectives

By the end of this lesson, you will be able to…

1Label the parts of a flower and explain the job each part does.
2Explain what pollination is, and describe self-pollination and cross-pollination.
3Describe the agents of pollination and the factors that affect how much pollination happens.
4Explain fertilization, and describe how a seed and a fruit are formed.
5Describe the agents of seed dispersal and explain why plants need to disperse their seeds.
6Carry out a simple investigation into a seed dispersal mechanism and use speed = distance ÷ time to describe results.

SupportUse the hints and diagrams whenever you need them.

CoreExplain each idea in your own words and try every activity.

ChallengeLook out for the orange “challenge” questions — they need extra thinking!

🧠 What do you already know?

Starter: male part or female part?

Flowers have male parts (which make pollen) and female parts (which make seeds). Sort these words into the correct box. If you get one wrong, that is fine — it helps us see where to begin!

💡 By the end of this lesson you will know exactly what each of these words means.

🌷 Structure of a flower

What is a flower actually for?

A flower is not just pretty to look at — it is the plant's reproductive organ. That is a fancy way of saying: it is the part of the plant that makes new plants.

Every flower is built from a set of parts, arranged in rings. Look closely at the labelled diagram below.

Diagram of a flower labelled with pollen, petal, anther, stigma, filament, style, ovary, ovule, sepal and stem

A typical flower and its parts

PETAL🔍 Click to reveal

The colourful, often scented part of a flower. Petals are not needed for reproduction itself, but they help attract pollinators like bees.

Example: A bright red hibiscus petal catches a bee's eye from far away.

SEPAL🔍 Click to reveal

A small, often green, leaf-like part that covers and protects the flower before it opens as a bud.

Example: The green flaps you see under a rose before it blooms.

Inside the ring of petals sit the two most important sets of parts: the male parts and the female parts. We will explore each of these next.

♂️ The male part

The stamen — where pollen is made

The stamen is the male part of the flower. Most flowers have several stamens, each made of two smaller parts.

Diagram showing the stamen made of anther and filament, with pollen inside the anther, and the pistil made of stigma, style and ovary

The stamen (male part) and the pistil (female part) of a flower

STAMEN🔍 Click to reveal

The complete male part of a flower. It is made of an anther sitting on top of a filament.

💡 Think of it like a little lollipop: the stick is the filament, the sweet head is the anther.

FILAMENT🔍 Click to reveal

The thin stalk that holds the anther up, lifting it into a good position for pollen to be picked up or blown away.

ANTHER🔍 Click to reveal

The small sac at the top of the stamen. This is where pollen is made and stored.

Example: The yellow dust that rubs off on your nose when you sniff a lily is pollen from the anther!

POLLEN🔍 Click to reveal

Tiny grains, often yellow, made inside the anther. Each pollen grain carries the plant's male sex cell, needed to make a new seed.

💡 Pollen is so light that a single sneeze from a person nearby can carry it away!

♀️ The female part

The pistil (carpel) — where seeds begin

The pistil (also called the carpel) is the female part of the flower, usually found right in the centre. It is made of three parts stacked on top of each other.

STIGMA🔍 Click to reveal

The sticky (or feathery) tip at the very top of the pistil. Its job is to catch pollen.

💡 Sticky stigmas trap pollen like glue traps dust.

STYLE🔍 Click to reveal

A tube-like stalk that connects the stigma to the ovary. Pollen grains grow a tube down through here.

OVARY🔍 Click to reveal

The rounded base of the pistil. It contains one or more ovules, and later grows into the fruit.

OVULE🔍 Click to reveal

A tiny structure inside the ovary. It contains the plant's female sex cell (the egg cell). After fertilization, an ovule becomes a seed.

Example: Each pip inside an apple grew from one ovule.

🎯Stigma catches pollen

→

🧵Style — the pathway down

→

🫙Ovary holds ovules

🎮 Matching activity

Match each flower part to its job

Tap a word, then tap its job. (On a computer you can also drag a word onto its job.)

🐝 Pollination begins

What is pollination?

Before a seed can form, pollen from an anther must reach a stigma. This journey is called pollination.

POLLINATION🔍 Click to reveal

The transfer of pollen from the anther of a flower to the stigma of a flower (of the same kind of plant).

💡 Pollination is NOT the same as fertilization — pollination is just the pollen arriving. Fertilization happens later, inside the ovule.

Try it: press the button and watch the bee. Predict first — where will the yellow pollen end up?

🔁 Two types of pollination

Self-pollination and cross-pollination

Diagram comparing cross pollination, where a bee carries pollen between two different flowers, and self pollination, where pollen moves within the same flower

Cross-pollination (top) compared with self-pollination (bottom)

SELF-POLLINATION🔍 Click to reveal

Pollen moves from the anther to the stigma of the same flower, or a different flower on the same plant.

💡 Reliable — happens even with no pollinators around. But it makes offspring very similar to the parent.

CROSS-POLLINATION🔍 Click to reveal

Pollen moves from the anther of one plant to the stigma of a different plant of the same species.

💡 Needs a pollinator or wind/water to carry the pollen across. Produces more varied, often stronger offspring.

🚚 Who delivers the pollen?

Agents of pollination

An agent of pollination is anything that carries pollen from one flower to another. Different flowers are specially built for different agents.

INSECT POLLINATION🔍 Click to reveal

Bees, butterflies and other insects visit flowers to drink nectar, and pollen sticks to their bodies by accident. Insect-pollinated flowers are usually brightly coloured, scented, and have sticky pollen and stigmas.

WIND POLLINATION🔍 Click to reveal

Pollen is carried on the breeze. Wind-pollinated flowers are usually small, dull-coloured, make huge amounts of light, smooth pollen, and have large feathery stigmas to catch pollen from the air.

Example: Grasses and maize (corn).

ANIMAL POLLINATION🔍 Click to reveal

Some flowers are pollinated by birds (like sunbirds and hummingbirds) or bats, which are attracted by nectar, bright colours, or a strong smell — even at night!

WATER POLLINATION🔍 Click to reveal

A few water plants release pollen that simply floats on the water's surface until it bumps into a stigma.

Example: Pondweed.

🧩 Sort the flower features

Which features belong to an insect-pollinated flower, and which belong to a wind-pollinated flower?

📊 Faster or slower?

What affects how much pollination happens?

Pollination does not always happen at the same rate. Several factors can speed it up or slow it down.

WEATHER🔍 Click to reveal

Calm, warm, dry days help insects fly and wind carry pollen. Cold, wet or very windy weather keeps pollinators away and can wash pollen off.

NUMBER OF POLLINATORS🔍 Click to reveal

More bees and insects nearby means more visits to flowers, so pollination happens faster.

💡 This is why a fall in bee numbers worries farmers.

FLOWER COLOUR & SCENT🔍 Click to reveal

Bright, strongly-scented flowers attract more insects, increasing the chance of pollination.

TIMING OF FLOWERING🔍 Click to reveal

Flowers that open at the same time as their pollinators are active (for example, in early morning or at night for bat-pollinated flowers) get pollinated more successfully.

Number of visiting insects3 insects → slow pollination

Try it: drag the slider. Observe how the bar and the number of pollinated flowers change.

💛 After pollination

Fertilization — making a new life

Landing on the stigma is only the beginning! Once a pollen grain lands on a stigma of the right kind of flower, an amazing journey starts.

Diagram of fertilization showing a pollen grain on the stigma growing a pollen tube down the style to the ovule, where the egg cell and other structures are found

The pollen tube grows from the stigma, down the style, into the ovule

POLLEN TUBE🔍 Click to reveal

A thin tube that grows out of a pollen grain, down through the style, all the way to an ovule.

FERTILIZATION🔍 Click to reveal

When the male sex cell (which travelled down the pollen tube) joins with the female egg cell inside the ovule.

ZYGOTE🔍 Click to reveal

The new cell formed when the male and female sex cells join. It will grow into the embryo of a new plant.

🌟 Challenge: the diagram also shows polar nuclei and antipodal cells. In many flowering plants a second male cell joins the polar nuclei to form a food store called the endosperm, which feeds the growing embryo. This is called double fertilization.

Observe: watch the pollen tube grow down the style, then watch the male cell travel down it to meet the egg cell.

🍏 After fertilization

From flower to fruit and seed

After fertilization, big changes happen inside the flower. The petals usually wither and fall off — they have done their job of attracting pollinators. Meanwhile, two parts of the pistil transform.

🫙Ovule

→

🌰Seed

🟢Ovary

→

🍎Fruit

SEED🔍 Click to reveal

A fertilized ovule. It contains an embryo (a tiny baby plant) plus a store of food, wrapped in a protective seed coat.

FRUIT🔍 Click to reveal

The ovary, after it has grown and often become fleshy. Its job is to protect the seeds and help them spread.

Example: A tomato is a fruit because it grew from an ovary and contains seeds — even though we eat it in salads!

EMBRYO🔍 Click to reveal

The tiny, undeveloped baby plant inside a seed, formed from the zygote. It will grow into a new plant when the seed germinates.

🧩 Put it all together

From flower to new plant

Put these steps of the plant life cycle in the correct order. Drag the cards using ☰, or use the ▲ ▼ buttons, then press Check order.

🚀 A new problem

Why do seeds need to travel?

Imagine hundreds of seeds falling straight down and growing right underneath their parent tree, all crowded together.

💡 Seeds that land far from the parent plant have a better chance of finding their own space, light, water and soil nutrients — with less competition. Moving seeds away from the parent plant is called seed dispersal.

SEED DISPERSAL🔍 Click to reveal

The spreading of seeds away from the parent plant, so new plants are not all competing in the same small space.

🚚 Who moves the seeds?

Agents of seed dispersal

WIND DISPERSAL🔍 Click to reveal

Light seeds with "wings" or fluffy "parachutes" are carried away by the breeze.

Example: Dandelion seeds and sycamore "helicopter" seeds.

WATER DISPERSAL🔍 Click to reveal

Some fruits float and are carried away by rivers, seas or floods.

Example: A coconut can float across the ocean to a new island!

ANIMAL DISPERSAL🔍 Click to reveal

Animals carry seeds in two main ways: by eating juicy fruit and later passing the seeds out in their droppings, far from the parent plant, or by seeds with hooks or burrs that stick to fur or clothing.

Example: A bird eats a berry; a burr sticks to a dog's fur.

EXPLOSIVE (SELF) DISPERSAL🔍 Click to reveal

Some seed pods dry out, build up tension, and suddenly burst open, flinging seeds away from the plant.

Example: A dry pea pod or gorse pod popping open on a hot day.

🧩 Sort the seeds and fruits

Which method of dispersal does each seed or fruit use?

🔬 Quantitative investigation

Investigating a winged seed

Some seeds, like the sycamore "helicopter" seed, have a wing that makes them spin as they fall. Spinning slows the fall, giving the wind more time to carry the seed away. Let's investigate how wing length affects falling speed.

1 Predict2 Try3 Observe4 Explain

Wing lengthShort wing

Drop height: 2 m. Set a wing length and press drop!

Try it: drop the seed with a short wing, note the time, then try a long wing. Observe what happens to the falling time.

💡 A longer wing means more air resistance (drag), so the seed spins and falls more slowly — giving the wind longer to blow it sideways, away from the parent tree.

🔬 Quantitative investigation

Investigating wind dispersal distance

A dandelion seed has a fluffy "parachute" that lets the wind carry it a long way. Let's investigate how wind strength changes the distance a seed travels.

Wind strengthGentle breeze

Distance travelled: — m

Try it: pick a wind strength and press blow. Observe the distance reading. Try a few different strengths.

🧮 Using your investigation data

Calculate the speed

Scientists use speed = distance ÷ time to describe how fast something moves — including falling seeds! Use this formula to answer the questions below.

speed = distance ÷ time

💡 Stuck? Cover "speed" in your mind and you are left with distance over time — that means distance ÷ time.

🌍 Why this matters

Pollination, dispersal, and our food

Around 1 in every 3 mouthfuls of food we eat depends on pollinators like bees. Farmers who grow apples, mangoes, cocoa and many other crops rely on insects to pollinate their flowers so that fruit can form.

GENETIC VARIATION🔍 Click to reveal

Differences between individual plants. Cross-pollination mixes genes from two different parent plants, creating offspring with new combinations of features — some of which may cope better with disease, drought, or pests.

POLLINATOR DECLINE🔍 Click to reveal

Bee and other pollinator numbers are falling in many places, due to habitat loss, pesticides and climate change. Fewer pollinators can mean less fruit and lower harvests.

💡 Planting flowers, avoiding harmful pesticides, and protecting wild habitats all help pollinators.

🏆 Final assessment

Show what you know!

10 questions, getting a little harder each time. You will see feedback after every answer.

✅ Lesson recap

The 6 things you should remember

1A flower's male part is the stamen (anther + filament), and its female part is the pistil (stigma + style + ovary + ovule).

2Pollination is pollen moving from anther to stigma. Self-pollination is within the same plant; cross-pollination is between different plants, carried by insects, wind, water or animals.

3Weather, the number of pollinators, flower colour/scent and timing all affect the rate of pollination.

4Fertilization happens when a pollen tube carries the male cell down to join the egg cell in the ovule, forming a zygote.

5After fertilization, the ovule becomes a seed and the ovary becomes a fruit, which protects and helps disperse the seeds.

6Seed dispersal (by wind, water, animals or explosive pods) spreads seeds away from the parent plant to reduce competition. speed = distance ÷ time helps us measure dispersal.

🗣️ Can you explain this to someone else?

Tell a friend or family member the full journey from a bee visiting a flower, all the way to a brand-new seedling growing far away. Try to use the words pollination, fertilization and dispersal.

Lesson complete!

Brilliant work exploring how flowers make pollen and seeds, how pollination and fertilization happen, and how seeds travel to new homes. You can jump back to any part using the map below.

Flower structure ✔Pollination ✔Fertilization ✔ Seeds & fruit ✔Seed dispersal ✔Investigations ✔

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