Primary Science: Seed Dispersal (Plants Reproduction)

Seeds spread in several clever ways

Seed dispersal means the movement of seeds away from the parent plant. This helps young plants survive.

If all the seeds fell right under the parent plant, they would have to compete for the same sunlight, space, water, and nutrients. Many would not grow well. By spreading out, seeds get a better chance.

Plants use different methods of seed dispersal.

Wind can carry light seeds

Some seeds are very light. They may have wings, hairs, or fluffy parts that catch the wind.

A dandelion seed is a great example. Each seed has a tiny parachute shape. When the wind blows, the seed floats away.

Maple seeds also travel by wind. They have wing-like parts that spin as they fall. Many people call them “helicopter seeds” because they twirl through the air.

Wind-dispersed seeds are usually small and light. They do not need animals to carry them.

Examples include:

• Dandelion seeds

• Maple seeds

• Milkweed seeds

• Cottonwood seeds

  
  

Water can float seeds to new places

Some plants grow near water, so their seeds travel by floating.

Coconut seeds can float in water because they have a tough outer covering and air spaces inside. This helps them move across water before washing onto land.

Water lilies and some pond plants also use water to spread seeds. Streams, rivers, ponds, and oceans can all carry seeds to new places.

Seeds that travel by water often have one or more of these features:

• A waterproof covering

• A tough outer layer

• Air spaces that help them float

  
  

Animals can carry or eat seeds

Animals help many plants spread seeds.

Some seeds stick to fur, feathers, or clothing. Burdock seeds have tiny hooks that catch onto animals as they pass. Later, the seed falls off in a new place.

Other seeds are inside fruits. Birds, squirrels, bears, and many other animals eat fruits. The seeds may be dropped, buried, or passed out later.

Squirrels spread seeds when they bury nuts and forget some of them. An acorn left in the soil can grow into an oak tree.

This is why many plants make fruits that look, smell, or taste attractive to animals. The plant is not just making food. It is also getting help moving seeds.

Some plants burst open

Some plants spread seeds by force. Their seed pods dry out and split open. When the pod bursts, seeds pop out and scatter.

This method is sometimes called explosive dispersal. It may sound dramatic, but it happens in small natural movements.

Pea pods, touch-me-not plants, and some wildflowers can scatter seeds this way. The seeds land away from the parent plant, where they may grow.

This kind of dispersal does not need wind, water, or animals. The plant uses the shape and drying of its own seed pod.

Why seed dispersal helps plants survive

Seed dispersal gives plants a better chance to live and reproduce.

It helps because seeds can:

• Find more space

• Reach better soil

• Get more sunlight

• Avoid competing with the parent plant

• Spread to new habitats

• Avoid some animals or diseases near the parent plant

  
  

A plant’s seed shape often gives clues about how it spreads. A fluffy seed probably travels by wind. A seed inside juicy fruit may travel by animal. A floating seed may travel by water. A hooked seed may catch on fur or clothing. A seed in a dry pod may be scattered when the pod bursts.