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 22-5 Interest Grabber 1. Memorial Day, President’s Day, and Independence Day are all examples 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. Go to Section:

Diversity of Flowering Plants Angiosperms—Flowering Plants A.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 Go to Section:

Diversity of Flowering Plants KEY CONCEPT The largest phylum in the plant kingdom is the flowering plants.

Diversity of Flowering Plants Stamen Anther Filament Petal Receptacle Ovule Sepal Stigma Style Ovary Carpel Draw Diagram

Diversity of Flowering Plants 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

Diversity of Flowering Plants 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 into pollen grains: male gametophytes. 2 Meiosis Pollen grains (n) Ovule Haploid spore in each ovule develops into female gameto- phyte, which produces an egg. 3 Pollination and growth of pollen tube Stigma Pollen grain Pollen tube 4 Fruit (mature ovary) 6 Seed 5 Ovary Ovule Stigma Anther Sporophyte (2n) Seed germinates, and embryo grows into plant. 7

Diversity of Flowering Plants 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

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

Diversity of Flowering Plants The structure of a fruit reflects its function in seed dispersal Copyright © 2009 Pearson Education, Inc. –Some rely on wind for seed dispersal –Some hitch a ride on animals –Fleshy, edible fruits attract animals

Diversity of Flowering Plants

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

Diversity of Flowering Plants 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

Diversity of Flowering Plants MonocotsDicots Seeds Leaves Flowers Stems Roots Single cotyledon Parallel veins Floral parts often in multiples of 3 Vascular bundles scattered throughout stem Fibrous roots Two cotyledons Branched veins Floral parts often in multiples of 4 or 5 Vascular bundles arranged in a ring Taproot Section 22-5 Figure 22–25Comparison of Monocots and Dicots Go to Section:

Diversity of Flowering Plants Flowering plants are also categorized by stem type and lifespan. Stem type can be woody or herbaceous. –Wood is a fibrous material made up of dead cells. –Wood has high concentrations of lignin and cellulose. –Woody stems are stiff. Oak

Diversity of Flowering Plants Flowering plants are also categorized by stem type and lifespan. Stem type can be woody or herbaceous. –Wood is a fibrous material made up of dead cells. –Wood has high concentrations of lignin and cellulose. –Woody stems are stiff. –Herbaceous plants do not produce wood. Iris

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

Diversity of Flowering Plants –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

Diversity of Flowering Plants –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.

Diversity of Flowering Plants are categorized as that complete their life cycle in Section 22-5 Concept Map Plants Annuals Biennials Perennials 1 growing season 2 years More than 2 years Go to Section:

Diversity of Flowering Plants CONNECTION: Angiosperms sustain us—and add spice to our diets Copyright © 2009 Pearson Education, Inc. 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

Diversity of Flowering Plants

EVOLUTION CONNECTION: Pollination by animals has influenced angiosperm evolution Copyright © 2009 Pearson Education, Inc. 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

Diversity of Flowering Plants

CONNECTION: Plant diversity is an irreplaceable resource Copyright © 2009 Pearson Education, Inc. 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