flowers are an important evolutionary advance made by flowering plants. some flowers are dependent upon the wind to move pollen between flowers of the same species. their pollen grains are light-weight. many others rely on insects or birds to move pollen. their pollen grains are heavier. the role of flowers is to produce seeds. these are inside what botanists call the fruit. fruits and seeds are a means of dispersal. plants do not move, but wind, animals and birds spread the plants across the landscape.