This preview shows page 1. Sign up to view the full content.
Unformatted text preview: phyte. This limits the size
in plants if male and female plants are separate, and limits mixing of genes to close neighbors.
• In conifers and flowering plants, the male gametophhyte is inside the pollen grain, while the female
gametophyte is inside of the embryo sac which is located in the cone or flower. This allows the male gamete
to be carried long distances, allowing crossing of plants over wider areas.
• Flowering plants have evolved a wide range of flowers, some highly specialized, to assist reproduction.
Wind-pollinated flowers are simple, and produce abundant dry pollen. Flowers pollinated by animals
(insects, birds, others) have developed showy petals to attract pollinators, may offer rewards such as nectar,
and often have sticky pollen.
• Flowers consist of four sets of parts: sepals, petals, stamens, and carpels. Flowers that have all of these
parts are called complete. Those that do not have all four parts are incomplete. Flowers that have both male
and female parts are called perfect, while those that are only male or only female are imperfect (and
• When a pollen grain lands on the stigma of a female carpel, it grows a pollen tube. The sperm cells swum
down the pollen tube to fertilize the ovule inside of the ovary. Notes Biology 103
Dr. Karen Bledsoe
http://www.wou.edu/~bledsoek/ • Seeds develop from fertilized ovules. The ovary swells to become a fruit. True fruits are swollen ovary walls.
Some things we call “fruits” may derive from other parts of the flower. (For example, a strawberry is actually
an enlarged pedicel, the part that holds up the flower. The individual “seeds” on the strawberry are the
actual fruits.) A single fruit may have one seed (as in a peach) or mul...
View Full Document