Seed dispersal is the transport or movement of seeds away from the parent plant in order to help prevent the overcrowding (if this happens plants would not have enough food and light to survive in the area) and help to create new colonies. Thus giving the seed the best chance to germinate in a new location away from the parent plant and hopefully start new colonies. Due to the fact plants have limited mobility they rely on a variety of dispersal vectors to transport their seeds via abiotic (non-living) and biotic (living) vectors. There are five main methods of seed dispersal, animals, gravity, wind, ballistic and water (1). Fire is also another way for seeds to be dispersed but is not as common as the other methods.
Biotic ways would be animals or Homo sapiens (humans). Animals disperse seeds (zoochory) in many ways because of this plants take advantage of animals and their ability to move, to help them disperse their seeds away from the parent plant. One way for the dispersal to happen if the animal were to ingest the seed, then the seed would be passed in their faeces (endozoochory) (2) such as strawberries, raspberries and nuts. Another would be for the seeds to get tangled in the animal’s fur or feathers and hitch a ride to another location, where it will eventually fall or be rubbed off by the animal, such as goose grass or sticky weed (3). Some animals would also bury seeds with the intention to return later to retrieve them. Such as a squirrel with acorns but it may not always be the case that they return (4). Humans would help with seed dispersal by the planting of the seeds or seeds becoming attached to clothes and shoes. Humans used to be classed as animals in seed dispersal however they can now sometimes be seen as an invasive species (one that does not belong). So for the dispersal of seeds via biotic vectors, animals play a very important part in the dispersal of these seeds. So if animals were never to come into contact with the plant these seeds would never be able to be dispersed (5).
Wind (anemochory) is an abiotic way to help with seed dispersal. For wind to work with dispersing of seeds, the seeds must be small and light in order for the wind to carry them. Making it possible for the wind to carry them over a great distance such as sycamore has stiff wings covering the seed so it spins in the wind to help it travel. Dandelion which is almost weightless but has a feathery pappus attached to the seed to increase the volume of the seed meaning it will only needs a light breeze for it to be carried away from the parent plant. Poppies need the wind to bend its stalk enough so as to allow its seeds to fall out of its seed pod (6). Because these seeds are smaller and lighter they have a smaller endosperm, meaning they have less nutrients to live on so many will never become established (5).
Water (hydrochory) is also an abiotic vector and helps many aquatic plants and some terrestrial plants to disperse their...