AP BIOLOGY

Detailed explanation-1: -In gymnosperms, a leafy green sporophyte generates cones containing male and female gametophytes; female cones are bigger than male cones and are located higher up in the tree. A male cone contains microsporophylls where male gametophytes ( pollen ) are produced and are later carried by wind to female gametophytes.

Detailed explanation-2: -Gymnosperms produce both male and female cones, each making the gametes needed for fertilization; this makes them heterosporous. Megaspores made in cones develop into the female gametophytes inside the ovules of gymnosperms, while pollen grains develop from cones that produce microspores.

Detailed explanation-3: -Gymnosperms are mainly conifers, such as pine and fir trees. They produce both male and female cones.

Detailed explanation-4: -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-5: -In most gymnosperms the male pollen cones, called microstrobili, contain reduced leaves called microsporophylls. Microsporangia, or pollen sacs, are borne on the lower surfaces of the microsporophylls. The number of microsporangia may vary from two in many conifers to hundreds in some cycads.