How can a seed travel away from its parent?

A dispersal structure has meaning in combination with a transport process. A wing affects aerodynamic behaviour; a hook provides mechanical attachment; buoyancy can allow water transport. Some seeds have several possible vectors or rely on animals eating fruits. The model isolates selected mechanisms without suggesting that plants choose destinations or that dispersal guarantees a new adult plant. External attachment and internal carriage are different routes; intact swallowed seeds can be deposited in animal droppings.