Why are some seeds edible?

Answer 1

Because they are not poisonous and taste nice. They are great roughage.

Answer 2

Seed producing plants have to have some way to disperse the seeds. The wider the area of dispersal, the greater the chance some of the seeds will be sucessful in growing. Some plants depend on the air to do this- like dandelions and the like. But most plants have become dependant on an animal to do the spreading around. Since the plant can't exactly ask a passing animal to do this favor, plants have adapted ways to entice animals, birds, or insects to do it. Primarily, this is done by encouraging the animals to eat the fruit of the plant. Not fruit like the food group, but the biology term for the seed containing portion of the plant. Some seeds are in a tasty container- like an apple. We don't tend to eat the seeds, but they are edible. Some seeds are resistant to our digestive tracts, like tomato seeds, and some just are designed to pass through the system faster- like corn. The main idea behind it all is to simply spread the seeds over as wide an area as possible, away from the parent plant, and hopefully in conditions favorable to growing.