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A Comprehensive Guide to Homeschooling

Seed dispersal


 

What are the main factors (conditions) that plants need to grow?

 

  • Sunlight
  • Water
  • Space or air
  • Warmth
  • Minerals

 

What will happen if all seeds of a plant fall under the parent plant?

 

If all seeds of a plant fall under the parent plant they will grow crowded together and many will die because of lack of space or air, water, sunlight and minerals. Therefore it is better seeds get scattered far and wide and have better chance of growing in a suitable place without over crowding.

What is ‘seed dispersal’?

The scattering or spreading of seeds to different places is called seed dispersal.

 

What are the special features in seeds for seed dispersal?

 

1) Some seeds are sticky and have hooks.

2) Some seeds have wings.

3) Some seeds have hairy parachutes.

4) Some seeds are in pods.

5) Some seeds have small holes in them.

6) Some seeds have spongy layers of fibres around them.

7) Some seeds have smaller spongy coverings.

 

Special features in seeds for seed dispersal

Sticky and have hooks Wings Hairy parachutes Pods Holes Spongy layers of fibres Spongy coverings
Goosegrass sycamore Dandelion peas Poppy Coconut Water lilies
Burdock ash thistle lupins orchid   Alder tree
Woodavens maple   laburnum      
  lime   gorse      

thistle
sycamore

 

Who are the agents of seed dispersal?

 

  • Wind
  • Water
  • Animals

 

water

 

 

wind

 

 

Wind

Seeds which have wings and hairy parachutes on them are carried by the wind.

E.g. – sycamore, ash, maple, lime, dandelion and thistle

 lime-tree

 

When pods dry, they split open suddenly and shooting the seeds away from the parent plant and this is easy when the wind is there.

E.g. – peas, lupins, laburnum and gorse

 

Some seeds have small holes in them, so they are very light in weight. When the wind rocks the plant, the seeds are scattered as if from a pepper pot.

E.g. – poppy and orchid fruits

 

Water

Some seeds have spongy layers of fibres around them. These can trap air so the seeds can float.

 

These seeds can travel, sometimes for hundreds of kilometers, from one island to another.

E.g. – Coconut

 

coconut-tree

 

Some seeds have smaller spongy coverings which lets them float in lakes and rivers.

E.g. – water lilies, alder trees

 

Animals

Brightly coloured and juicy fruits are often eaten by animals like birds. The hard seeds inside these fruits pass out of the animal’s body in its droppings.

E.g. – blackberries, strawberries, raspberries and gooseberries

 

The seeds may finish up a long way from where they were first eaten.

 

Animals like squirrels and jays bury some nuts, ready to eat later. These animals often forget where they have hidden their food, and some of these seeds can grow.

 squirrels-birds-seed-dispersal

 

Some seeds and fruits have hooks that catch on the fur or feathers of animals or on people’s clothes. If the seeds eventually drop off on the soil, they may grow.

E.g. – goosegrass, burdock, wood avens