+ SEED DISPERSAL Why is it important? Are there disadvantages?

+ BENEFITS TO SEED DISPERSAL Survival of seeds Seed dispersal

+ TYPES OF DISPERSAL There are basically five main types of seed dispersal Wind Water Gravity Ballistic or Ejecting of Seeds Animals.

+ GRAVITY Plants with fruits that are heavy disperse their seeds by the fruit falling to the ground and rolling some distance away from the tree.

+ GRAVITY The fruit may germinate there by the parent plant or it may be carried away or eaten by an animal. It may also fall into the water and float away to another area.

+ WIND This type of dispersal is a rather primitive means of dispersal. Seeds from plants may either float in the wind or they can just flutter to the ground. Because the seeds are being dispersed by the wind the plant must produce an abundance of seeds to ensure that at least some of them reach a suitable place to germinate and grow to maturity.

+ WIND Many of these seeds are comprised of various types of fluff that can be carried by the slightest breeze for long distances giving the seed a chance to germinate. Some plants need the wind to shake them to release their seeds. The seed pod may face up or down and need the wind to bend and shake their stems hard enough to cause the seeds to be released.

+ WIND Can you think of some seeds that you have seen floating down from trees or just floating on the wind toward a new place to grow?

+ WATER Dispersal of seeds in water provides a means for seeds to travel a long distance. Some examples of water dispersal are: Water Lily Mangrove Tree.

+ WATER Water lily fruits float for a time in the water and then they sink to the bottom of the water body and take root. The Mangrove tree seeds begin to germinate while it is still on the tree but the roots do not grow until the seed falls into the water when it is about a foot long. As soon as the seed touches the bottom it begins to root

+ ANIMAL There are a number of ways that animals disperse seeds of plants. The seeds have various ways to attaching themselves to animals. These include: small hooks or burs stiff hairs mucus The seeds can then attach themselves to animals. Sometimes these types of seeds are referred to as “hitch-hikers”. If you take a walk through a weeded area you will often find these on your socks or legs of your pants. They attach themselves to animal fur also

+ ANIMALS Animals also ingest (eat) fruits and seeds and then pass them through their system to germinate in other places. We may overlook some species as agents of dispersal such as Chimpanzees, which gather things like figs. They eat some, carry some to other places, and even drop some of the fruit.

+ ANIMALS Ants are another important animal in dispersal of seeds. They gather plants that are rich in lipids that attract the ants. The ants feed their off spring in their nests and the seeds therefore are protected underground where they will later germinate.

+ ANIMALS Other animals gather seeds to save for later such as squirrels and some birds. They store their seeds in a place away from the parent plant. Those that are not eaten are left to germinate in areas away from where they fell.

+ ANIMALS Dispersal by humans can lead to problems with invasive species being introduced into areas where they may cause problems in the environment where they are introduced.

+ BALLISTIC OR EJECTION Many plants eject or fling their seeds out of the seedpods. The basic way that this occurs is that the seedpod dries up due to evaporation of water in the seedpod.

+ BALLISTIC OR EJECTION The seedpods have varying ways of causing the seed to disperse. Some of them dry up faster on the side facing the sun, which causes the seedpod to pop open. Others have very specific mechanisms.

+ BALLISTIC OR EJECTION A very elastic coating covers the Oxalis seed. When it dries it splits very suddenly, catapulting individual seeds in many directions out of the pod.

+ ENVIRONMENTAL ISSUES Our impact on the environment may cause the extinction of a plant due to our habits, which may somehow limit the dispersal of the seeds Can you think of some ways that we might cause a problem with seed dispersal and possibly harm the environment? Can you come up with a solution?