diversity of flowering plants it’s a plant’s life not all plants have the same life span. for...

Diversity of Flowering Plants

•It’s a Plant’s Life

•Not all plants have the same life span. For this reason, scientists divide plants into different categories. Two such categories are annuals and biennials.

Section 22-5Interest Grabber

1. Memorial Day, President’s Day, and Independence Day are allexamples of annual holidays. Using this information, how often does an annual event occur?

2. Bimonthly magazines are published every two months. Biweekly newspapers are published every two weeks. Using this information,how often does a biennial event occur?

3. Distinguish between the life spans of annual plants and biennial plants.

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Angiosperms—Flowering PlantsA. Flowers and Fruits

B. Diversity of Angiosperms

1. Monocots and Dicots

2. Woody and Herbaceous Plants

3. Annuals, Biennials, and Perennials

Section 22-5

Section Outline

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KEY CONCEPT The largest phylum in the plant kingdom is the flowering plants.


Stamen

Anther

Filament

Petal

Receptacle

Ovule

Sepal

Stigma

Style

Ovary

Carpel

Draw Diagram


The angiosperm plant is a sporophyte with gametophytes in its flowers

Copyright © 2009 Pearson Education, Inc.

• The angiosperm life cycle

1. Meiosis in the anthers produces haploid spores that form the male gametophyte (pollen grains)

2. Meiosis in the ovule produces a haploid spore that forms a tiny female gametophyte, including the egg

3. A pollen tube from the pollen grain to the ovule carries a sperm that fertilizes the egg to form a zygote

4. Each ovule develops into a seed, consisting of an embryo (a new sporophyte) with a food supply and a seed coat

5. The ovary wall forms a fruit


Meiosis

1

Haploid (n)

Diploid (2n)

Key

Egg (n)

Fertilization

Sperm

Seed coat

Zygote(2n)

Food supply

Embryo (2n)

Seeds

Haploid spores in anthers develop intopollen grains: male gametophytes.

2

Meiosis

Pollen grains (n)

Ovule

Haploid spore in each ovuledevelops into female gameto-phyte, which produces an egg.

3 Pollination andgrowth of pollen tube

Stigma

Pollen grain

Pollen tube

4

Fruit(matureovary)

6

Seed5

OvaryOvule

Stigma

Anther

Sporophyte (2n)

Seed germinates,and embryogrows intoplant.

7


Flowering plants have unique adaptations that allow them to dominate in today’s world. • Flowers allow for efficient pollination.

– animals feed on pollen or nectar – pollen is spread from plant to plant in process


• Fruit allows for efficient seed dispersal. – Fruit is flower’s ripened ovary– Surrounds and protects seed(s) – Many forms, each function in seed dispersal


The structure of a fruit reflects its function in seed dispersal


– Some rely on wind for seed dispersal– Some hitch a ride on animals– Fleshy, edible fruits attract animals


Botanists classify flowering plants into two groups based on seed type. • A cotyledon is an embryonic “seed leaf.” • Monocots have a single seed leaf.

– leaf veins usually parallel– flower parts usually in multiples of 3 – bundles of vascular tissue scattered in stem


• Dicots have two seed leaves.

– leaf veins usually netlike – flower parts usually in multiples of 4 or 5 – bundles of vascular tissue in rings in stem


Monocots Dicots

Seeds

Leaves

Flowers

Stems

Roots

Single cotyledon

Parallel veins

Floral parts often in multiples of 3

Vascularbundlesscattered throughout stem

Fibrous roots

Two cotyledons

Branched veins

Floral parts often in multiplesof 4 or 5

Vascularbundlesarranged ina ring

Taproot

Section 22-5Figure 22–25 Comparison ofMonocots and Dicots

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Flowering plants are also categorized by stem type and lifespan.

• Stem type can be woody or herbaceous. – Wood is a fibrous

material made up ofdead cells.

– Wood has highconcentrations oflignin and cellulose.

– Woody stemsare stiff.

Oak


Flowering plants are also categorized by stem type and lifespan.

• Stem type can be woody or herbaceous. – Wood is a fibrous

material made up ofdead cells.

– Wood has highconcentrations oflignin and cellulose.

– Woody stemsare stiff.

– Herbaceous plants do not produce wood.

Iris


• There are three types of plant life spans. – Annuals mature from seed,

flower, and die in one year.

Wheat


– Biennials take two years to compete life cycle.

• There are three types of plant life spans. – Annuals mature from seed,

flower, and die in one year.

Foxglove


– Annuals mature from seed, flower, and die in one year.• There are three types of plant life spans.

– Perennials live more than two years.

Big bluestem

– Biennials take two years to compete life cycle.


are categorized as

that completetheir life cycle in



Section 22-5

Concept Map

Plants

Annuals Biennials Perennials

1 growingseason 2 years

More than2 years

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CONNECTION: Angiosperms sustain us—and add spice to our diets


• Most human food is provided by the fruits and seeds of angiosperms

– Corn, rice, wheat, and other grains are dry fruits– Apples, cherries, tomatoes, and squash are fleshy

fruits– Spices such as nutmeg, cinnamon, cumin, cloves,

ginger, and licorice are also angiosperm fruits


EVOLUTION CONNECTION: Pollination by animals has influenced angiosperm evolution


• 90% of angiosperms use animals to transfer pollen– Birds are attracted by colorful flowers, but not scent– Beetles are attracted by fruity odors, but not color– Bats are attracted by large, highly scented flowers– Wind-pollinated flowers produce large amounts of

pollen


CONNECTION: Plant diversity is an irreplaceable resource


• More than 50,000 square miles of forest are cleared every year

– Replanted areas have greatly reduced biological diversity

• Loss of forests has greatly reduced diversity of life on Earth– The loss of plant diversity removes potentially

beneficial medicines– More than 25% of prescription drugs are extracted

from plants

diversity of flowering plants it’s a plant’s life not all plants have the same life span. for...

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