AP BIOLOGY

Detailed explanation-1: -Storage tissue to sustain growth and a protective coat give seeds their superior evolutionary advantage. Several layers of hardened tissue prevent desiccation, freeing reproduction from the need for a constant supply of water.

Detailed explanation-2: -Four major adaptations are found in all terrestrial plants: the alternation of generations, a sporangium in which the spores are formed, a gametangium that produces haploid cells, and apical meristem tissue in roots and shoots.

Detailed explanation-3: -We’ll revisit this point later on in this course, so for now, just know that pollen protects sperm from desiccation and provides a means for sperm to reach the egg in the absence of water. Seeded nonflowering plants rely on wind to transport pollen (and therefore sperm) to eggs.

Detailed explanation-4: -Over millions of years, flowers have developed scents, colors, markings and shapes to attract certain pollinators, and certain pollinators have developed characteristics such as long tongues or beaks that enable them to reach the nectar in differently shaped flowers.

Detailed explanation-5: -The Sporoderm structure, its chemical constituents and the diverse aperture types of pollen grains, has possibly developed as a need to adaptation in response to their respective habitats and mode of pollination.