[maratharibe (OP)]

I was taught that the blossoms attract bees and bees are an important part of the pollination process.  And pollination is a necessary step in producing seeds that produce the next generation of seedlings.  Unpollinated plants produce no seeds.  That's a formula for extinction.




mod edit - spam link removed

[CliffordK]

There are several different models of propagation.  The diploid genetic structures provide genetic stability which is important for higher organisms, although not vital for lower organisms such as bacteria, yeasts, and molds. 

Flowers, pollen, and various sugars promote insect based cross pollination.  However, many trees and other plants favor spores and airborne pollination (thus pollen counts and allergies).

Seeds can be distributed through ingestion & defecation such as is done with many fruits and berries.  Flight as done with dandelions and maple seeds.  Planting by squirrels as done with many nuts, or snagging onto the coats of passerbys such as is done with burrs, and many grasses.