In this module, you will learn:
- the importance of seed dispersal
- recognise the different methods for seed dispersal
Resources to help you:
- Textbook: page 138 and 139
- Notebook: page 35 and 36
What happens after fertilisation?
After fertilisation, the flower develops into the fruit and the seed(s). The seed contains the embryo which will develop into a young plant but before that can happen it needs to be moved to a suitable place to grow.
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Learn about different methods of dispersal
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It is important for the dispersal of seed to be away from the parent plant.
This is to prevent overcrowding. Overcrowding means that too many plants are growing in a small amount of space. This is not healthy for the plants because when all the plants are close together, they are competing for nutrients, water and sunlight.
When a plant does not get enough nutrients, water or sunlight, it will not grow optimally and may even die.
Credit: @germanopoli via DepositPhotos
The methods of dispersal
There are four main methods of seed dispersal:
- wind dispersal
- water dispersal
- animal dispersal
Characteristics of a wind-dispersed fruit or seed
- they are light
- they have wing-like or parachute-like structures
- they can have hair like structures surrounding their seeds
Close up of a dandelion
Credit: @velkol via YayImages
A shorea fruit (meranti)
Credit: @Satakorn via YayImages
Dandelion seed getting carried by the wind
Credit: @Janetta via YayImages
Coconut husk has air trapped to allow it to float.
Credit: Lana_M via YayImages
The lotus pod floats on water.
Credit: @magann via DepositPhotos
Characteristics of a water-dispersed fruit or seed
- Fruits or seeds that can float on water
- Parent plants live near or on water.
The coconut has trapped air inside the husk giving it a density less that water. This allows it to float on water.
Characteristics of a animal-dispersed fruit or seed
- Fruits that are fleshy and juicy
- Seeds with tough coats to protect from being digested
- Fruits or seeds with spikes or hooks to attach to animal fur or clothings
A monkey eating from a fruit and throwing away the seeds.
Credit: @cloudyew via YayImages
Different self dispersal fruits
Characteristics of a self-dispersed fruit or seed
- seeds stored in pods
- fruit dries and explode
Ready for the next module?
In the next module, we will look at the germination of seeds.