Biotic Dispersal methods
ZOOCHORY
Zoochory is the dispersal of seeds by animals. Seeds can be dispersed by animals in several ways. The two main categories of zoochory are epizoochory, where seeds are transported externally by the animal, and endozoochory, where seeds are transported internally by the animal.
Common methods of Zoochory: (A) Attachment (Epizoochory) - Seeds must have adaptations such as barbs, adhesive mucus, spines, or hooks to attach to the animals fur to be carried to a new area. (B) Burial (Epizoochory) - Some seeds will be buried by an animal with the intention to be eaten later. The animal may not always make it back to the buried seed, and it will grow into a new plant. (C) Defication (Endozoochory) - Seeds are surrounded by an edible, fleshy fruit that attracts animals to them. The fruits are taken up by the animal, and then passed and dropped in a new location. These seeds can now germinate in this new location. (D) Spitting (Synzoochory) - While chewing the fruit, some animals will spit the seeds out, dispersing them away from their original location. Other methods of Zoochory: 1. Chiropterochory - Dispersal by Bats 2. Malacochory - Dispersal by Molluscs 3. Ornithochory - Dispersal by Birds 4. Myrmecochory - Dispersal by Ants |
AUTOCHORY
Autochory is a form of self seed dispersal occurring mainly in fruits. Seeds forcibly disperse themselves by means of many different mechanisms. Some seeds need only an increase in temperature or moisture to trigger their dispersal. Ballistics is the main form of autochory, where seeds explode from the plant or seed capsules.
Common methods of Ballistics: (A) Heat - The heat of the sun causes the outer coverings of the plants to dry and crack. When the coverings crack, the seeds are forcibly shot out and dispersed. (B) Moisture (Creeping Diaspores) - When moistened, bristles of the plant bury themselves like a corkscrew. They unwind a barbed appendage into the soil that was previously coiled while dry. (C) Osmotic Pressure - A build up of osmotic pressure, from the passage of water across the cell membrane, causes the plant to burst, forcibly dispersing the seeds outwards. (D) Ballochory - Dehiscence is the splitting along a mature line of weakness in a plants structure. With ballochory, the seeds are forcibly squeezed out along this line of weakness, dispersing them outwards. |
ANTHROPOCHORY
Anthropochory is the dispersal of seeds by human. Humans can disperse seeds in various ways. Most methods of anthropochory are unintentional. However, there are some intentional methods of seed dispersal by humans.
Common methods of Anthropochory: (A) Clothes - Dispersal by clothes is the most common mode of dispersal by humans. Burrs commonly stick to pants, socks, and shirts when brushing past the plant carrying them. Just as they do with animal attachment, the seeds must have adaptations such as barbs, adhesive mucus, spines, or hooks to attach to the passing humans clothes. (B) Shoes - Seeds can be dispersed by shoes the same as clothes, by sticking to them when passing by. Another way of dispersal by shoes is through clumps of feces. Unknowingly stepping in clumps of feces spreads the contained seeds wherever you step. (C) Seed Bombing - Seed bombing is used to introduce vegetation to a new area. Seed bombs are clumps of soil, clay, or other biodegradable material with live vegetation or seeds contained inside. They are scattered in a new area to introduce vegetation not previously found there. |