Q.Both gymnosperms and angiosperms bear seeds, then why are they classified separately?

Gymnosperms and angiosperms both bear seeds but differ fundamentally in whether the seed is naked or enclosed in fruit, in their fertilization process, and in the presence of true flowers — differences significant enough to place them in separate groups.

Both gymnosperms and angiosperms are seed-bearing (spermatophyte) plants, but they differ from each other in several fundamental reproductive and structural features that justify their separate classification. First, and most definitionally, gymnosperm ovules (and the seeds they develop into) are 'naked' — they are borne exposed on the surface of sporophylls, usually arranged in cone-like structures, and are not enclosed within an ovary at the time of pollination (the very term 'gymnosperm' means 'naked seed'). In angiosperms, by contrast, the ovules are always enclosed within an ovary, which develops into a fruit after fertilization, so the seeds inside are always enclosed ('angiosperm' means 'covered seed'). Second, gymnosperms lack true flowers altogether, reproducing via cones (strobili), whereas angiosperms are defined by bearing true flowers as their reproductive structures. Third, the fertilization process itself differs: gymnosperms undergo only single fertilization (fusion of one male gamete with the egg cell to form the zygote), while angiosperms undergo double fertilization — one male gamete fuses with the egg to form the zygote, and a second male gamete fuses with the two polar nuclei to form the triploid primary endosperm nucleus, which develops into nutritive endosperm tissue unique to angiosperm seeds. Because of these deep differences in seed exposure, presenc …