AP BIOLOGY

Detailed explanation-1: -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-2: -Most gymnosperms produce seeds in structures called cones or strobili (singular strobilus; Figure 8.1. 2). Cones evolved from modified leaves, and they can either be male cones that produce pollen, or female cones that produce ovules.

Detailed explanation-3: -They are typically slow to reproduce; up to a year may pass between pollination and fertilization, and seed maturation may require 3 years. All gymnosperms are heterosporous and have two types of cones: male, which are smaller and female, which tend to be larger.

Detailed explanation-4: -Gymnosperm seeds are usually formed in unisexual cones, known as strobili, and the plants lack fruits and flowers. Both groups use pollen to facilitate fertilization, though angiosperms have an incredible diversity of pollination strategies that are not found among the gymnosperms.

Detailed explanation-5: -Next time you pick up a pine cone, look for loose seeds inside. Male cones make pollen, which is carried to female cones by the wind. After the female gametes are fertilised by male gametes from the pollen, the female cones produce seeds.