campbell's chapter 30 plants

Evolution of Seed Plants Overview: Seeds changed the course of plant evolution, enabling their bearers to become the dominant producers in most terrestrial ecosystems A seed consists of an embryo and nutrients surrounded by a protective coat Seeds and pollen grains are key adaptations for life on land In addition to seeds, the following are common to all seed plants Reduced gametophytes. The evolutionary trend from nonvascular plants to seedless vascular plants to seed plants has been a reduction in the size of the gametophyte. In seed plants, the gametophyte is usually microscopic and is retained within the tissues of the sporophyte. Heterospory (production of 2 different kinds of spores) Advantages of reduced gametophytes