Transcript Seed Plants
Seed Plants Seed plants are divided into two groups: • 1. gymnosperms – which bear their seeds directly on the surface of cones. • Gymnosperms include conifers such as pine and spruce, palmlike plants called cycads, ginkgoes, and the very weird gnetophytes. • http://videos.howstuffworks.com/d iscovery/30697-assignmentdiscovery-gymnosperms-video.htm Phylum Gymnosperm • Gymno = naked sperma = seed “naked seed” no covering around seed • Do not flower • Produce cones (acorns, pine) • Shallow roots and woody stems • Leaves are needle-like and are replaced every 2 – 4 years. Gymnosperm continued • Needles retain moisture even during cold seasons. • Grow all year • Can grow in harsh environments (cold, poor soil) • Used for lumber, making paper, wood chips Pollen cone Seed Cone • The pollen falls down into the seed cone and fertilization results in a zygote which grows into an embryo inside a seed. • As the seed ripens, the cone opens and releases the seeds. If the ground is favourable, it will grow. • The pollen cone releases million of pollen into the air which is why allergies can be triggered in the spring. Life cycle of a gymnosperm • Cones are either male or female: - female cone is the seed cone and found at the bottom of the tree - male cone is the pollen cone and found in the upper tree Angiospermae • 2. Angiosperms (also called flowering plants) bear their seeds within a layer of tissue that protects the plant. • http://videos.howstuffworks.com /discovery/27703-assignmentdiscovery-angiosperms-video.htm Angiospermae • Angio = covered seed sperma = seed Covered seed • Produce flowers (which are unique reproductive systems) • Soft stems (herbaceous) • Broad leaves (not needles) • Deep roots • Grow in summer only (deciduous) Pollination • Pollination is the pollen moving from the male part of the plant to the female part of the plant. Pollination can take place in 2 ways: 1. Self-pollination: occurs in some flowers. Pollen from the anther fertilizes the ovule (egg) of the same plant. 2. Cross-pollination: a. birds, insects feed on the nectar. – attracted to flower colour, scent, shape therefore they go to the same type of flower – carry pollen from plant to plant while feeding b. wind - blows pollen around Success of angiosperm is due to: • Flowers – Do not have to depend on wind or water to fertilize/reproduce • Fruit – The wall of tissue that surrounds the seed protects it and is usually delicious. As a result, they are often eaten. By the time the seeds have cleared the animal’s digestive system and are ready to sprout, they may have travelled many kilometers. Angiosperm are categorized in 3 ways: 1. Monocots (Monocotyledon)and Dicots (Dicotyledon) Monocots and dicots are named for the number of seed leaves or cotyledons in the plant embryo. Seeds of the dicot (left) and monocot (right) • Add to chart the chart above (see page 570 in your text: Monocots Dicots Fibrous root Taproot Another way to group angiosperms 2. By their stems: Woody or herbaceous Woody: trees, grapes, some ivy, blueberries, roses Herbaceous: dandelions, petunias, sunflowers Herbaceous and Woody Another way: 3. Annuals, biennials, perennials Annuals: Complete their life cycle in one year (grow, flower, produce seeds and die in one year Biennials: complete their life cycle in two years Perennials: live for more than 2 years