Describe how fruits and seeds are suited to their modes of dispersal.
Answer Text: Animal dispersal- Fleshy fruits are eaten by animals.- Animals are attracted to the fruits by the bright colour, scent or the fact that it is edible.- The seeds pass through the digestive tract undamaged and are passed out with faeces. E.g. tomatoes and guavas.- Such seeds have hard, resistant seed coats.- Others have fruits with hooks or spines that stick on animal fur or on clothes.- Later the seeds are brushed of or fall off on their own e.g. Bidens pilosa (Black jack). Wind dispersal- Fruits and seeds are small and light in order to be carried by air currents.- A fruit that is a capsule e.g. tobacco split or has pores at the top e.g. Mexican poppy.- The capsule is attached to along stalk when swayed by wind the seeds are released and scattered.- Some seeds have hairy or feather-like structures which increase their surface area so that they can be blown off by the wind e.g. Sonchus.- Others have wing-like structures e.g. Jacaranda and Nandi Flame.- These extensions increase the surface area of fruits and seeds such that they are carried by the wind. Water dispersal- Fruits like coconut have fibrous mesocarp which is spongy to trap air, the trapped air make the fruit light and buoyant to float on water.- Plants like water lily produce seeds whose seed coats trap air bubbles.- The air bubbles make the seeds float on water and are carried away.- The pericarp and seed coat are waterproof. Self dispersal (explosive) Mechanism- This is seen in pods like bean and pea.- Pressure inside the pod forces it to open along lines of weakness throwing seeds away from parent plant.
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