AP BIOLOGY

Detailed explanation-1: -Gymnosperms. The term gymnosperm (“naked seeds”) represents four extant divisions of vascular plants whose ovules (seeds) are exposed on the surface of cone scales. The cone-bearing gymnosperms are among the largest and oldest living organisms in the world. They dominated the landscape about 200 million years ago.

Detailed explanation-2: -gymnosperm, any vascular plant that reproduces by means of an exposed seed, or ovule-unlike angiosperms, or flowering plants, whose seeds are enclosed by mature ovaries, or fruits. The seeds of many gymnosperms (literally, “naked seeds”) are borne in cones and are not visible until maturity.

Detailed explanation-3: -Female Cones – the megasporophylls form a cluster and are called as the female strobili or cones. They bear the ovules having the megasporangium. Thus produces the haploid megaspores and a megaspore mother cell. The megaspore mother cell undergoes meiotic division produces four megaspores.

Detailed explanation-4: -The Gymnosperms (Conifers, cycads and allies) Gymnosperms are seed-bearing vascular plants, such as cycads, ginkgo, yews and conifers, in which the ovules or seeds are not enclosed in an ovary. The word “gymnosperm” comes from the Greek word gymnospermos, meaning “naked seeds".

Detailed explanation-5: -Angiosperms and gymnosperms are the two major groups of vascular seed plants. Angiosperms, which are flowering plants, are the largest and most diverse group within the kingdom Plantae.