Dispersal

Plants compete with each other for factors such as:

  • light
  • water
  • space
  • minerals in the soil

Seeds must be dispersed or spread away from each other and from the parent plant. This is to reduce competition between the parent plant and the new plants, and between the new plants.

Sycamore maple seed
Sycamore maple seed

The table describes the most common methods of seed dispersal:

MethodDetailExamples
WindSeeds have lightweight parts, wings or parachutesDandelion, sycamore
Animals (inside)Brightly coloured and tasty fruits contain seeds with indigestible coats, so that the seeds pass through the animal’s digestive system undamagedTomato, plum, raspberry, grape
Animals (outside) Fruits have hooks that attach them to the fur of passing animalsGoose grass, burdock
Self-propelledHave a pod that bursts open when ripe, throwing the seeds away from the plantPea pod

Investigating dispersal

Seeds dispersed by the wind are easier to investigate than seeds dispersed by other methods. For example, you could release sycamore seeds and measure the distance they travel. Factors that could affect the distance travelled by a sycamore seed include:

  • the height from which it is released
  • the surface area of the wings
  • the mass of the seed
  • the wind speed

There are a number of different ways plant seeds can be dispersed

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