Topics · Primary Science · Cycles: Seed Dispersal & Germination
Seed dispersal and germination
Seeds have to get away from the parent plant, and then they have to start growing. Two separate processes, and papers test the difference between what a seed needs to travel and what it needs to sprout.
- 227 exam papers analysed
- appears in 66% of P6 Science papers
- ~3 min read
01 Why seeds must travel
If every seed fell under its parent, the seedlings would compete with the parent and with each other for water, mineral salts, sunlight and space. Most would die.
So dispersal spreads them out. It also lets a plant reach new places where nothing is growing yet.
A question asking why dispersal matters wants the competition answer — naming the four things they would compete for scores better than “so they can spread out”.
02 The four ways, and how to tell them apart
You can read the method off the seed itself, which is exactly what papers ask you to do with an unnamed drawing.
- Wind — light, with wings or hairs to catch the air. Angsana, dandelion.
- Water — light, waterproof, with a fibrous husk or air pockets to float. Coconut.
- Animals, outside — hooks, spines or a sticky surface that catches on fur. Love grass.
- Animals, inside — a fleshy, brightly coloured, sweet fruit that gets eaten; the seeds pass through and are dropped elsewhere. Tomato, papaya.
- Splitting (explosive) — the dried pod bursts open and flings the seeds. Balsam, rubber tree.
03 Germination: what a seed needs
Germination is the seed beginning to grow. It needs exactly three things, and papers test the list precisely.
Water, air and a suitable temperature — that is all.
Sunlight is not needed to germinate. A seed has its own store of food inside it, so it can sprout in the dark. Light matters afterwards, once the seedling must make its own food.
Soil is not needed either. A seed germinates on damp cotton wool, which is exactly why classroom experiments use it.
04 The experiment they always use
Several jars of seeds, each missing one condition. Which germinate, and why not?
No water — will not germinate. No air, usually shown by seeds under boiled water or fully submerged — will not. Too cold, in a fridge — will not, or very slowly.
No light — will germinate perfectly well. This is the set-up children get wrong, and it is included on purpose.
Watch for two things changed at once. A jar in a dark fridge tests two conditions, so it cannot tell you which one mattered — the fair-test rule applies here as everywhere.
05 How to say them
These are words most children have never said out loud, and a word you cannot say is a word you avoid using. Capitals mark the syllable you lean on. Tap the speaker to hear it.
- dispersalsaydi-SPUR-suhl
The scattering of seeds away from the parent plant.
- germinationsayjur-mi-NAY-shuhn
A seed beginning to grow into a seedling.
- seedlingmore than oneseedlings
The young plant that grows from a germinating seed.
- competesaykuhm-PEET
To need the same limited things as something else — water, sunlight, space, mineral salts.
- fibrous husksayFY-bruhs
The light, air-filled covering that lets a coconut float.
- podmore than onepods
A dry case holding seeds. Some split open and fling them out.
06 What each level is tested on
The same topic, asked differently as it goes up. The percentage is the share of papers at that level in which it appears.
- P4
Recognising seeds and how they travel.
Practise P4 Cycles: Seed Dispersal & Germination — 10 questions →19% of P4 papers
- P5
The methods of dispersal and the features that suit each, and what germination needs.
Practise P5 Cycles: Seed Dispersal & Germination — 9 questions →58% of P5 papers
- P6
Germination experiments, why dispersal matters, and links to competition and the environment.
Practise P6 Cycles: Seed Dispersal & Germination — 9 questions →66% of P6 papers
07 Mistakes worth knowing about
Each of these is wrong. Decide why before you open it.
“Seeds need sunlight to germinate.”
They do not. A seed has stored food inside it and germinates in the dark. Light is needed after, once the seedling must make food.
“Seeds need soil to germinate.”
Water, air and a suitable temperature. Damp cotton wool works, which is why experiments use it.
“Seeds are dispersed so the plant can spread.”
Partly, but the marked answer is that seedlings would otherwise compete with the parent and each other for water, sunlight, space and mineral salts.
“A coconut is dispersed by wind because it is big.”
It floats — a fibrous husk with air pockets and a waterproof shell. Wind-dispersed seeds are light with wings or hairs.
“Germination and dispersal are the same stage.”
Dispersal is the seed travelling; germination is it starting to grow. Different needs, different questions.
Now try it
28 questions across 3 levels, marked as you go with the working shown.