Grade 5 · Unit 2: The life cycle of flowering plants

How seeds are spread

Seeds travel – and the wind can carry them far.

In a forest, tall trees shade the ground, leaving little light for young plants.

Why spread seeds?

If all the seeds fell right under the parent plant, the young plants would be crowded. They would have to fight for light, water and space. This is competition. So plants spread their seeds away. This is called seed dispersal.

Seedlings growing under a parent tree also compete with its roots for water and minerals in the soil.

Blown by the wind

Some seeds are carried by the wind. They are light, and they may have wings or fluffy hairs. In spring, fluffy cotton from the shimul (silk cotton) tree floats through the air with seeds inside.

Each shimul seed sits in a ball of silky fluff. In the past the fluff was used to stuff pillows and mattresses.

Wings and parachutes

Dandelion seeds have tiny parachutes of hairs. Maple and mahogany seeds have wings that spin like helicopters as they fall. These shapes slow the seed down so the wind can carry it further.

Scientists and engineers study spinning seeds to design better drones and parachutes.

Testing wind dispersal

You can make model seeds from paper. Time how long they take to fall, or measure how far a fan blows them. Seeds that fall slowly are carried further by the wind.

Scientists use models like paper spinners because they can change one feature at a time, such as wing length, and test it fairly.

What I learnt