Seed Plants. Seed plants are divided into two groups: 1. gymnosperms – which bear their seeds...

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.

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Phylum Gymnosperm

• Gymno = nakedsperma = 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) – which bear their seeds within a layer of tissue that protects the plant.

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Angiospermae

• Angio = covered seedsperma = seed Covered seed

• Produce flowers (which are unique reproductive systems)

• Soft stems (herbaceous)

• Broad leaves

• 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:

3. Self-polliation:occurs in some flowers

4. Cross-pollinators: 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. One way: Two classes with the angiosperm: 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, perennialsAnnuals: 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