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,

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2 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

3 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

4 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

5 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

6 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

7 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

8 Plants What Is a Plant? The Diversity of Plants Plant Structure and Function Reproduction in Plants

9 Chapter 21 What 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 21 Summary Chapter 21 Assessment

10 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.

11 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.

12 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.

13 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.

14 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.

15 Origins of Plants The first evidence of plants in the fossil record began to appear over 440 million years ago.

16 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.

17 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.

18 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.

19 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.

20 Preventing water loss Most fruits, leaves, and stems are covered with a protective, waxy layer called the cuticle.

21 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.

22 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.

23 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.

24 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.

25 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.

26 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.

27 Transporting materials Phloem Xylem Xylem transports water and dissolved substances other than sugar throughout the plant. Cambium Phloem transports dissolved sugar throughout the plant. Cambium produces xylem and phloem as the plant grows.

28 Transporting materials Mosses and several other small, less familiar plants called hornwarts and liverworts are usually classified as nonvascular plants.

29 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.

30 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.

31 Reproductive strategies Embryo Seed Coat Food Supply Adaptations in some land plants include the evolution of seeds.

32 Reproductive strategies Embryo Seed Coat Food Supply A seed is a plant organ that contains an embryo, along with a food supply, and is covered by a protective coat.

33 Reproductive strategies Embryo Seed Coat Food Supply A seed protects the embryo from drying out and also can aid in its dispersal.

34 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.

35 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 nonseed plants require wetter habitats than most seed plants.

36 Alternation of generations The lives of all plants include two stages, or alternating generations. Spores (n) Meiosis Gametophyte (n) Sporophyte (2n) Male Female gamete (n) gamete (n) Fertilization Mitosis and cell division

37 Alternation of generations The gametophyte generation of a plant results in the development of gametes. All cells of the gametophyte, including the gametes, are haploid (n). Spores (n) Meiosis Gametophyte (n) Sporophyte (2n) Male Female gamete (n) gamete (n) Fertilization Mitosis and cell division

38 Alternation of generations The sporophyte generation begins with fertilization. All cells of the sporophyte are diploid (2n) and are produced by mitosis and cell division. Spores (n) Meiosis Gametophyte (n) Sporophyte (2n) Male Female gamete (n) gamete (n) Fertilization Mitosis and cell division

39 Alternation of generations The spores are produced in the sporophyte plant body by meiosis, and are therefore haploid (n). Spores (n) Meiosis Gametophyte (n) Sporophyte (2n) Male Female gamete (n) gamete (n) Fertilization Mitosis and cell division

40 Alternation of generations In non-seed vascular plants such as ferns, spores have hard outer coverings.

41 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.

42 Alternation of generations In seed plants, such as conifers and flowering plants, spores develop inside the sporophyte and become the gametophytes.

43 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.

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

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

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

47 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.

48 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.

49 Section Objectives: Describe the phylogenic relationships among divisions of plants. Identify the plant kingdom divisions.

50 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.

51 Phylogeny of Plants These processes of evolution and extinction continue to be affected by local and global changes. As plant species evolved in this changing landscape, they retained many of their old characteristics and also developed new ones. These processes of evolution and extinction continue today.

52 Phylogeny of Plants The highlights of plant evolution include origins of plants from green algae, the production of a waxy cuticle, the development of vascular tissue and roots, and the production of seeds. The production of seeds can be used as a basis to separate the divisions into two groups non-seed plants and seed plants.

53 Non-seed Plants Non-seed plants include vascular or nonvascular organisms.

54 Hepaticophyta Hepaticophytes (heh PAH tih koh fites) include small plants commonly called liverworts.

55 Hepaticophyta Liverworts are nonvascular plants that grow only in moist environments. Water and nutrients move throughout a liverwort by osmosis and diffusion. Studies comparing the biochemistry of different plant divisions suggest that liverworts may be the ancestors of all plants.

56 Hepaticophyta There are two kinds of liverworts: thallose liverworts and leafy liverworts. Thallose liverworts have a broad body that looks like a lobed leaf. Leafy liverworts are creeping plants with three rows of thin leaves attached to a stem.

57 Anthocerophyta Anthocerophytes (an THOH ser oh fites) are also small thallose plants. The sporophytes of these plants, which resemble the horns of an animal, give the plants their common name hornworts. These nonvascular plants grow in damp, shady habitats and rely on osmosis and diffusion to transport nutrients.

58 Bryophyta Bryophytes (BRI uh fites), the mosses, are nonvascular plants that rely on osmosis and diffusion to transport materials.

59 Bryophyta However, some mosses have elongated cells that conduct water and sugars. Moss plants are usually less than 5 cm tall and have leaflike structures that are usually only one to two cells thick. Their spores are formed in capsules.

60 Psilophyta Psilophytes, known as whisk ferns, consist of thin, green stems.

61 Psilophyta The psilophytes are unique vascular plants because they have neither roots nor leaves. Small scales that are flat, rigid, overlapping structures cover each stem. The two known genera of psilophytes are tropical or subtropical. Only one genus is found in the southern United States.

62 Lycophyta Lycophytes (LI koh fites), the club mosses, are vascular plants adapted primarily to moist environments.

63 Lycophyta Lycophytes have stems, roots, and leaves. Their leaves, although very small, contain vascular tissue. Ancestors grew as tall as 30 m and formed a large part of the vegetation of Paleozoic forests.

64 Lycophyta The plants of these ancient forests have become part of the coal that is now used by people for fuel.

65 Arthrophyta Arthrophytes (AR throh fites), the horsetails, are vascular plants.

66 Arthrophyta They have hollow, jointed stems surrounded by whorls of scalelike leaves. The cells covering the stems of some arthrophytes contain large deposits of silica. About 15 species of arthrophytes exist today.

67 Pterophyta Pterophytes (TER oh fites), ferns, are the most well-known and diverse group of non-seed vascular plants.

68 Pterophyta They have leaves called fronds that vary in length from 1 cm to 500 cm. The large size and complexity of fronds is one difference between pterophytes and other groups of seedless vascular plants. Although ferns are found nearly everywhere, most grow in the tropics.

69 Seed Plants Seed plants produce seeds, which in a dry environment are a more effective means of reproduction than spores.

70 Seed Plants Embryo Seed coat Food supply A seed consists of an embryonic plant and a food supply covered by a hard protective seed coat. All seed plants have vascular tissues.

71 Cycadophyta Cycads (SI kuds) were abundant during the Mesozoic Era. Today, there are about 100 species of cycads. They are palmlike trees with scaly trunks and can be short or more than 20 m in height. Cycads produce male and female cones on separate trees.

72 Cycadophyta Cones are scaly structures that support male or female reproductive structures. Seeds are produced in female cones. Male cones produce clouds of pollen.

73 Gnetophyta There are three genera of gnetophytes (NEE toh fites) and each has distinct characteristics. Gnetum (Nee tum) includes about 30 species of tropical trees and climbing vines. There are about 35 Ephedra (eh FEH dra) species that grow as shrubby plants in desert and arid regions.

74 Gnetophyta Welwitschia (wel WITCH ee uh) has only one species, which is found in the deserts of southwest Africa. Its leaves grow from the base of a short stem that resembles a large, shallow cap.

75 Ginkgophyta This division has only one living species, Ginkgo biloba, a distinctive tree with small, fan-shaped leaves.

76 Ginkgophyta Ginkgoes (GING kohs) have male and female reproductive structures on separate trees. The seeds produced on female trees have an unpleasant smell, so ginkgoes planted in city parks are usually male trees. Ginkgoes are hardy and resistant to insects and to air pollution.

77 Coniferophyta These are the conifers (KAH nuh furz), conebearing trees such as pine, fir, cypress, and redwood.

78 Coniferophyta Conifers are vascular seed plants that produce seeds in cones. Species of conifers can be identified by the characteristics of their cones or leaves that are needlelike or scaly.

79 Coniferophyta Bristlecone pines, the oldest known living trees in the world, are members of this plant division. Another type of conifer, the Pacific yew, is a source of cancer-fighting drugs.

80 Anthophyta Anthophytes (AN thoh fites), commonly called the flowering plants, are the largest, most diverse group of seed plants living on Earth.

81 Anthophyta There are approximately species of anthophytes. Unlike conifers, anthophytes produce flowers from which fruits develop.

82 Anthophyta A fruit usually contains one or more seeds. This division has two classes: the monocotyledons (mah nuh kah tul EE dunz) and dicotyledons (di kah tul EE dunz).

83 Question 1 Which of the following characteristics do plants NOT share with algae? A. bioluminescent B. multicellular C. autotrophic D. eukaryotic The answer is A.

84 Question 2 Which of the following plant products is made of vascular tissue? A. nuts B. seeds C. wood D. moss The answer is C.

85 Question 3 Plants share alternation of generations with which of the following? A. viruses B. fungi C. algae D. bacteria The answer is C.

86 Question 4 Which of the following are probably the ancestors of all plants? A. liverworts B. fungi C. slime molds D. downy mildews The answer is A.

87 Adapting to Life on Land Plants are multicellular eukaryotes with cells that have cell walls containing cellulose. A waterproof cuticle covers the outer surface of most plants. Most plants undergo photosynthesis, which produces glucose, a form of food.

88 Adapting to Life on Land All plants on Earth probably evolved from filamentous green algae that lived in ancient oceans. The first plants to eventually move from water to land probably were leafless forms. Adaptations for life on land include a cuticle; the development of leaves, roots, stems, and vascular tissues; alternation of generations; and the evolution of the seed.

89 Survey of the Plant Kingdom The plant kingdom is grouped into major categories called divisions. Nonvascular plants are in the divisions Anthocerophyta, Hepaticophyta, and Bryophyta. They reproduce mainly by using spores. Nonvascular plants do not produce seeds.

90 Survey of the Plant Kingdom Non-seed vascular plants are in the divisions Psilophyta, Lycophyta, Arthrophyta, and Pterophyta. These plants have tissues that conduct water and other materials and reproduce mainly by spores.

91 Survey of the Plant Kingdom Vascular seed plants in the divisions Cycadophyta, Gnetophyta, Ginkgophyta, and Coniferophyta produce seeds on cones. Male cones and female cones can be on separate plants or the same plant.

92 Survey of the Plant Kingdom The division Anthophyta includes vascular, seed-producing plants that flower. Fruits with seeds develop from flowers. Anthophytes are divided into two groups monocotyledons and dicotyledons.

93 Question 1 Which of the following divisions does not move water and nutrients by osmosis and diffusion? A. Hepaticophyta B. Anthocerophyta C. Bryophyta D. Psilophyta The answer is D.

94 Question 2 What difference between lycophytes and psilophytes allowed lycophyte ancestors to grow so tall? Answer Lycophytes possess roots that would have been able to anchor a tall plant in the ground. Psilophytes do not posses roots, and would not be able to stand very tall without falling over.

95 Question 3 Scaly structures that support male or female reproductive structures on conifers are called. A. spores B. fronds C. cones D. seeds The answer is C.

96 Question 4 Which of the following is the youngest plant division? A. Cycadophyta B. Lycophyta C. Coniferophyta D. Anthophyta The answer is D.

97 Question 5 Which of the following does not produce seeds on cones? A. Cycadophyta B. Gnetophyta C. Pterophyta D. Coniferophyta The answer is C.

98 Question 6 Drugs that fight have been derived from the Madagascar rosy periwinkle and the Pacific yew. A. sickle-cell disease B. Down syndrome C. AIDS D. cancer The answer is D.

99 Question 7 Identify the following structure and the parts of the structure, describing how the parts contribute to the structure s biological success.

100 The structure is a seed. Inside the seed is an embryo plant. The embryo is surrounded by a food supply that nourishes it until it can get food from its environment and also by a tough seed coat that protects the embryo from drying out. Embryo Seed coat Food supply

101 Question 8 The oldest living plants in the world are members of the division. A. Cycadophyta B. Coniferophyta C. Anthophyta D. Ginkgophyta The answer is B.

102 Question 9 Nearly of the world s population relies on medications derived from plants. A. 10% B. 50% C. 80% D. 20% The answer is C.

103 Question 10 Which of these divisions has only one living species? A. Gnetophyta B. Ginkgophyta C. Cycadophyta D. Hepaticophyta The answer is B.

104 Photo Credits PhotoDisc Mark Thayer Aaron Haupt Matt Meadows Digital Stock Doug Martin Geoff Butler Randy Witherspoon David M. Dennis Thomas Russell Chris Klaming Alton Biggs

105 To advance to the next item or next page click on any of the following keys: mouse, space bar, enter, down or forward arrow. Click on this icon to return to the table of contents Click on this icon to return to the previous slide Click on this icon to move to the next slide Click on this icon to open the resources file.

106 End of Chapter 21 Show