Presentation From Lavender

Video on seed dispersal

http://www.youtube.com/watch?v=zbQ1jWl3AOM

Other methods on dispersal

1. In order to deal with the realities of dispersal, plants have evolved specific structures and strategies to carry their seeds throughout the environment. Some seeds have two lateral wings to help them glide. Dandelions and salsifies use umbrella-like parachutes instead. Other seeds are known as "helicopters" or "whirlybirds" because they have spinning wings.

2. The wind is not the only method for seed dispersal. Seeds also can hitch rides on animals, preferably winged animals such as insects, bats and birds, as they usually travel the greatest distances. Other methods include travel by water and "ballistics" that fling seeds away from the plant at great speeds.

Why Is Seed Dispersal Important To Plants?

After plants have already fertilized and grown seeds, dispersal is the last important step before the new offspring finally establish independence on their own. There are a number of reasons why seed dispersal is integral to the survival of a plant species, but the methods of dispersal are varied.

Before they can grow into new plants, seeds need to leave the seed pod. If all the seeds a plant produced landed just underneath the parent plant, they would be too crowded, and the established large plant might not leave them enough light or water for them all to develop properly. When you plant seeds too thickly in a pot, you can see that they grow tall and leggy, and each plant is weak and spindly. The various methods of seed dispersal are designed to ensure that as many seeds as possible have a good chance of growing up to produce seeds of their own.

On some plants native to Australia and South Africa, the seedpods may need the heat of the natural bush fires occurring in these areas to open and release their seeds, which are then dispersed by other means.

                         

Sometimes, the pod or fruit containing the seeds is carried away from the parent plant; sometimes, individual seeds are spread to a new location. The size and shape of the seedpod or the seeds influences how they are dispersed. The main methods plants use to disperse their seeds to places with better growing conditions than directly under the parent plant include gravity, animals, force, wind and water. Often, a plant will spread its seeds by a combination of these methods. For instance, a fruit falling to the ground by gravity might then be carried away by animals, or a seed blown by the wind might land in water and be transported somewhere else before germinating.

Quiz time!!!!!

Q1:Name 1 type of dispersal of seeds.

Ans :Water/ Force/ Wind/ Animal/ Splitting/ Gravity

Q2: What does the seed need to leave first before it can grow into a new plant?

Ans:The seed pod

Quiz time!!!!!Q3:Are individual seeds spread to a new location?

Ans :Yes

Q4:what will happen when the seed is fertilised and grown seeds?

Ans:dispersal

By Khee Ing , Azmina ,Ryan ,Justin.

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