Table of Contents – pages iv-v

Table of Contents – pages iv-v Unit 1:What is Biology? Unit 2:Ecology Unit 3:The Life of a Cell Unit 4:Genetics Unit 5:Change Through Time Unit 6:Viruses, Bacteria, Protists, and Fungi Unit 7:Plants Unit 8:Invertebrates Unit 9:Vertebrates Unit 10:The Human Body

Table of Contents – pages iv-v Unit 1: What is Biology? Chapter 1:Biology: The Study of Life Unit 2: Ecology Chapter 2:Principles of Ecology Chapter 3:Communities and Biomes Chapter 4:Population Biology Chapter 5:Biological Diversity and Conservation Unit 3:The Life of a Cell Chapter 6:The Chemistry of Life Chapter 7:A View of the Cell Chapter 8:Cellular Transport and the Cell Cycle Chapter 9:Energy in a Cell

Unit 4: Genetics Chapter 10:Mendel and Meiosis Chapter 11:DNA and Genes Chapter 12:Patterns of Heredity and Human Genetics Chapter 13:Genetic Technology Unit 5: Change Through Time Chapter 14:The History of Life Chapter 15:The Theory of Evolution Chapter 16:Primate Evolution Chapter 17:Organizing Life’s Diversity Table of Contents – pages iv-v

Unit 6: Viruses, Bacteria, Protists, and Fungi Chapter 18:Viruses and Bacteria Chapter 19:Protists Chapter 20:Fungi Unit 7: Plants Chapter 21:What Is a Plant? Chapter 22:The Diversity of Plants Chapter 23:Plant Structure and Function Chapter 24:Reproduction in Plants Table of Contents – pages iv-v

Table of Contents – pages iv-v Unit 8: Invertebrates Chapter 25:What Is an Animal? Chapter 26:Sponges, Cnidarians, Flatworms, and Roundworms Chapter 27:Mollusks and Segmented Worms Chapter 28:Arthropods Chapter 29:Echinoderms and Invertebrate Chordates

Table of Contents – pages iv-v Unit 9: Vertebrates Chapter 30:Fishes and Amphibians Chapter 31:Reptiles and Birds Chapter 32:Mammals Chapter 33:Animal Behavior Unit 10: The Human Body Chapter 34:Protection, Support, and Locomotion Chapter 35:The Digestive and Endocrine Systems Chapter 36:The Nervous System Chapter 37:Respiration, Circulation, and Excretion Chapter 38:Reproduction and Development Chapter 39:Immunity from Disease

Unit Overview – pages 556 - 557 Plants What Is a Plant? The Diversity of Plants Plant Structure and Function Reproduction in Plants

Chapter Contents – page x Chapter 21What Is a Plant? 21.1:Adapting to Life on Land 21.1:Section Check 21.2:Survey of the Plant Kingdom 21.2:Section Check Chapter 21Summary Chapter 21Assessment

Chapter Intro – pages 558 What You’ll Learn You will identify and evaluate the structural adaptations of plants to their land environments. You will survey and identify the major divisions of plants.

21.1 Section Objectives – page 559 Section Objectives: • Compare and contrast characteristics of algae and plants. • Identify and evaluate structural adaptations of plants to their land environments. • Describe the alternation of generations in land plants.

Section 21.1 Summary – pages 559 - 563 Origins of Plants • A plant is a multicellular eukaryote. • Most plants can produce their own food in the form of glucose through the process of photosynthesis. • Plant cells have thick cell walls made of cellulose. • The stems and leaves of plants have a waxy waterproof coating called a cuticle.

Section 21.1 Summary – pages 559 - 563 Origins of Plants • Scientists hypothesize that all plants probably evolved from filamentous green algae that lived in the ancient oceans. • Some of the evidence for their relationship can be found in modern members of both groups.

Section 21.1 Summary – pages 559 - 563 Origins of Plants • Green algae and plants have cell walls that contain cellulose. • Both groups have the same types of chlorophyll used in photosynthesis and store food in the form of starch.

Section 21.1 Summary – pages 559 - 563 Origins of Plants • The first evidence of plants in the fossil record began to appear over 440 million years ago.

Section 21.1 Summary – pages 559 - 563 Origins of Plants • These early plants were simple in structure and did not have leaves. • They were probably instrumental in turning bare rock into rich soil.

Section 21.1 Summary – pages 559 - 563 Adaptations in Plants • All organisms need water to survive. • For most land plants, the only available supply of water and minerals is in the soil, and only the portion of the plant that penetrates the soil can absorb these nutrients.

Section 21.1 Summary – pages 559 - 563 Adaptations in Plants • Land plants evolved structural and physiological adaptations that help protect the gametes from drying out. • In some plants, the sperm are released near the egg so they only have to travel a short distance.

Section 21.1 Summary – pages 559 - 563 Adaptations in Plants • Other plants have protective structures to ensure the survival of the gametes. • Land plants must also withstand the forces of wind and weather and be able to grow against the force of gravity.

Section 21.1 Summary – pages 559 - 563 Preventing water loss • Most fruits, leaves, and stems are covered with a protective, waxy layer called the cuticle.

Section 21.1 Summary – pages 559 - 563 Preventing water loss • Waxes and oils are lipids, which are biomolecules that do not dissolve in water. • The waxy cuticle creates a barrier that helps prevent the water in the plant’s tissues from evaporating into the atmosphere.

Section 21.1 Summary – pages 559 - 563 Carrying out photosynthesis • The leaf, is a plant organ that grows from a stem and usually is where photosynthesis occurs. • Each plant species has unique leaves or leaflike structures.

Section 21.1 Summary – pages 559 - 563 Putting down roots • Plants can take in water and nutrients from the soil with their roots. • In most plants, a root is a plant organ that absorbs water and minerals usually from the soil.

Section 21.1 Summary – pages 559 - 563 Putting down roots • Roots anchor a plant usually in the ground. • Some roots, such as those of radishes or sweet potatoes, accumulate starch and function as organs of storage.

Section 21.1 Summary – pages 559 - 563 Transporting materials • Water moves from the roots of a tree to its leaves, and the sugars produced in the leaves move to the roots through the stem. • A stem is a plant organ that provides support for growth.

Section 21.1 Summary – pages 559 - 563 Transporting materials • It contains tissues for transporting food, water, and other materials from one part of the plant to another. • Stems also can serve as organs for food storage. • In green stems, some cells contain chlorophyll and can carry out photosynthesis.

Section 21.1 Summary – pages 559 - 563 Transporting materials Xylem transports water and dissolved substances other than sugar throughout the plant. Phloem Xylem Phloem transports dissolved sugar throughout the plant. Cambium Cambium produces xylem and phloem as the plant grows.

Section 21.1 Summary – pages 559 - 563 Transporting materials • Mosses and several other small, less familiar plants called hornwarts and liverworts are usually classified as nonvascular plants.

Section 21.1 Summary – pages 559 - 563 Transporting materials • Nonvascular plants do not have vascular tissues. • The bodies of nonvascular plants are usually no more than a few cells thick, and water and nutrients travel from one cell to another by the process of osmosis and diffusion.

Section 21.1 Summary – pages 559 - 563 Transporting materials • Vascular plants can live farther away from water than nonvascular plants. • Also, because vascular tissues include thickened cells called fibers that help support growth, vascular plants can grow much larger than nonvascular plants.

Section 21.1 Summary – pages 559 - 563 Reproductive strategies Embryo • Adaptations in some land plants include the evolution of seeds. Seed Coat Food Supply

Section 21.1 Summary – pages 559 - 563 Reproductive strategies • A seed is a plant organ that contains an embryo, along with a food supply, and is covered by a protective coat. Embryo Seed Coat Food Supply

Section 21.1 Summary – pages 559 - 563 Reproductive strategies Embryo • A seed protects the embryo from drying out and also can aid in its dispersal. Seed Coat Food Supply

Section 21.1 Summary – pages 559 - 563 Reproductive strategies • Land plants reproduce by either spores or seeds. • In non-seed plants, which include mosses and ferns, the sperm require a film of water on the gametophyte plant to reach the egg.

Section 21.1 Summary – pages 559 - 563 Reproductive strategies • In seed plants, which include all conifers and flowering plants, sperm reach the egg without using a film of water. • This difference is one reason why non-seed plants require wetter habitats than most seed plants.

Section 21.1 Summary – pages 559 - 563 Alternation of generations Male gamete (n) Female gamete (n) Spores (n) • The lives of all plants include two stages, or alternating generations. Gametophyte (n) Meiosis Fertilization Sporophyte (2n) Mitosis and cell division

Section 21.1 Summary – pages 559 - 563 Alternation of generations Male gamete (n) • The gametophyte generation of a plant results in the development of gametes. Female gamete (n) Spores (n) Gametophyte (n) Meiosis Fertilization Sporophyte (2n) Mitosis and cell division • All cells of the gametophyte, including the gametes, are haploid (n).

Section 21.1 Summary – pages 559 - 563 Alternation of generations Male gamete (n) Female gamete (n) • The sporophyte generation begins with fertilization. All cells of the sporophyte are diploid (2n) and are produced by mitosis and cell division. Spores (n) Gametophyte (n) Meiosis Fertilization Sporophyte (2n) Mitosis and cell division

Section 21.1 Summary – pages 559 - 563 Alternation of generations Male gamete (n) Female gamete (n) • The spores are produced in the sporophyte plant body by meiosis, and are therefore haploid (n). Spores (n) Gametophyte (n) Meiosis Fertilization Sporophyte (2n) Mitosis and cell division

Section 21.1 Summary – pages 559 - 563 Alternation of generations • In non-seed vascular plants such as ferns, spores have hard outer coverings.

Section 21.1 Summary – pages 559 - 563 Alternation of generations • Spores are released directly into the environment where they can grow into haploid gametophyte plants. • These plants produce male and female gametes. • Following fertilization, the sporophyte plant develops and grows on the gametophyte plant.

Section 21.1 Summary – pages 559 - 563 Alternation of generations • In seed plants, such as conifers and flowering plants, spores develop inside the sporophyte and become the gametophytes.

Section 21.1 Summary – pages 559 - 563 Alternation of generations • The gameotophytes consist of only a few cells. • Male and female gametes are produced by these gametophytes. • After fertilization, a new sporophyte develops within a seed. The seed eventually is released and the new sporophyte plant grows.

Section 1 Check Question 1 Most plants produce their own food in the form of _______. A. cellulose B. proteins C. glucose D. chlorophyll The answer is C.

Section 1 Check Question 2 Which of the following did NOT precede land plants? A. corals B. sponges C. amphibians D. jellyfish The answer is C.

Section 1 Check Question 3 Which of the following did early plants NOT possess? A. stems B. chlorophyll C. vascular systems D. leaves The answer is D.

Section 1 Check Question 4 Why are most plant roots not covered in a cuticle? Answer The waxy cuticle would prevent the plant’s roots from absorbing water and nutrients.

Section 1 Check Question 5 Which of the following is NOT a function of most plant roots? A. absorbing water and nutrients B. conducting photosynthesis C. store starch D. anchoring the plant The answer is B.

21.2 Section Objectives – page 564 Section Objectives: • Describe the phylogenic relationships among divisions of plants. • Identify the plant kingdom divisions.

Section 21.2 Summary – pages 564 - 569 Phylogeny of Plants • Many geological and climate changes have taken place since the first plants became adapted to life on land. • Hundreds of thousands of plant species evolved, and countless numbers of these became extinct as conditions continually changed.

Table of Contents – pages iv-v