Gymnosperms and angiosperms, the scientific classifications given to seed-bearing plants that don't flower and flower respectively, are actually recent additions to the planet, having been around for a mere 360 million years or so, according to Dr. Paul Ciesielski with the University of Florida. It is believed that they hailed from seedless aquatic plants and evolved to spread over dry land. Today, thanks to their proliferation and diversity, they comprise the vast majority of plants. Their importance is multi-faceted and they remain essential to animals and humans.
Food for Animals
Cold winters illustrate how much wildlife depends upon seed-bearing plants for survival. Cardinals, sparrows and other birds in particular feast on berries from angiosperms and flock to feeders filled with seeds. Squirrels spend the summer and fall seasons storing walnuts to dig up and munch on in between sleeps on snowy days. Deer help themselves to fruit ripening in gardens, to the chagrin of growers.
Food for Humans
People, like animals, also rely on seed-bearing plants to thrive. Such plants provide necessary vitamins, nutrients and flavor to meals. Some plants, such as sunflowers, are grown specifically for their seeds. With others, such as pumpkins, seeds are also eaten along with the flavorful fruit pulp. Edibles, from riddichio to rice, come from seed bearers.
Seeds aren't the only parts of a plant that have value. Certain plants also provide necessary non-edible materials. Walnut and oak trees, for instance, are favored for their strong wood, which is fashioned into furniture. Wood that is less structurally sound, such as pine, is used to make fire. Marijuana plants, while most infamous for offering smokable vegetation that is illegal in the United States, is also known for its sturdy, woody branches that can be peeled and fashioned into hemp fiber.
Seeds themselves are survival adaptations. Gymnosperms, such as conifers, feature exposed seeds with a protective, strong outer coating. Not only are they able to withstand extreme weather conditions, but they reproduce without exposure to moisture. Angiosperms, such as tomatoes, with their seeds and pollen necessary for species perpetuation, have seed coverings that are soft and fleshy.
Dispersal also helps to ensure a plant's survival. By equipping itself with features that allow seeds to travel, these plants also make possible plant diversity, which is also necessary for animal and plant survival. Cotton willows, for instance, spread their seeds via the wind by growing lightweight fiber that carries seeds. Plants with fruit and nuts encapsulate seeds efficiently enough for animals and people to carry away, thus making it possible for Ohioans to receive Georgia peaches through the mail and British gardeners to plant heirloom tomato seeds from Thomas Jefferson's Monticello plantation in Virginia.
Aside from their practicalities, seed-bearing plants' appearances can't be discounted. Sunflowers, after all, are grown just as much for their seeds as for their large, showy blooms. Peonies are cultivated for their color and fragrance. Landscapes benefit from rose gardens and butterfly bushes, just as gardens do from purple hybrid string beans and bright yellow squash. The world would be a barren, colorless place without seed-bearing plants.