Presentation is loading. Please wait.

Presentation is loading. Please wait.

Chapter 22 Plant Diversity.

Similar presentations

Presentation on theme: "Chapter 22 Plant Diversity."— Presentation transcript:

1 Chapter 22 Plant Diversity

2 22–1 Introduction to Plants

3 Objectives Explain what a plant is
Describe what plants need to survive Describe how plants first evolved

4 What Is a Plant? Plants are members of the kingdom Plantae
Plants are multicellular eukaryotes that have cell walls made of cellulose. They develop from multicellular embryos and carry out photosynthesis using the green pigments chlorophyll a and b

5 The Plant Life Cycle Plants have life cycles that are characterized by alternation of generations the two generations are the haploid (N) gametophyte, or gamete-producing plant, and the diploid (2N) sporophyte, or spore-producing plant.




9 What Plants Need to Survive
Sunlight Water and Minerals Gas Exchange Movement of water and nutrients

10 Early Plants The first plants evolved from an organism much like the multicellular green algae living today.

11 The First Plants  The first true plants were still dependent on water to complete their life cycles, similar to today’s mosses in that they were simple in structure and grew close to the ground.

12 From these plant pioneers, several major groups of plants evolved.

13 Mosses

14 Ferns

15 Cone Bearing Plant

16 Flowering plant

17 Overview of the Plant Kingdom
Botanists divide the plant kingdom into four groups based on three important features: Water conducting tissues Seeds Flowers



20 22 – 2 Bryophytes a.k.a (Non-vascular plants)

21 Objectives Describe the adaptations of Bryophytes

22 bryophytes Type of early plant with no vascular tissue that draw water in their cells by osmosis.

23 Moss

24 Liverwort

25 Hornwort

26 During at least one stage of their life cycle, bryophytes produce sperm that must swim through water to reach eggs of other individuals. Therefore, they must live in places where there is rainfall or dew for at least part of the year

27 Asexual Reproductive Part
Sexual Reproductive/ Photosynthetic Part

28 22–3 Seedless Vascular Plants

29 Objectives Explain how vascular tissue is important to ferns and their relatives Describe the three phyla of spore-bearing plants Identify the stages in the cycle of ferns

30 In just a few million years, plants grew to a whole new scale on the landscape.
Q: What caused this increase in size? A: Vascular Tissue

31 Vascular tissue A type of tissue that is specialized to conduct water and nutrients through the body of the plant

32 Evolution of Vascular Tissue
Both forms of vascular tissue—xylem and phloem—can move fluids throughout the plant body, even against the force of gravity.

33 Xylem Carry water upwards from the roots to every part of the plant

34 Phloem Transports nutrients and carbohydrates produced by photosynthesis from the leaves down to the roots


36 Vascular plants also evolved the ability to produce lignin, a substance that makes cell walls rigid.
The presence of lignin allows vascular plants to grow upright and tall

37 Ferns and Their Relatives
Seedless vascular plants include club mosses, horsetails, and ferns. Like other vascular plants, ferns and their relatives have true roots, leaves, and stems.

38 Roots Absorb water and minerals

39 Leaves Collect light for photosynthesis

40 Veins Made of xylem and phloem

41 Stems Used for support, connect roots and leaves, carry water between them

42 Club Mosses 

43 Horsetails

44 Ferns Underground Stem


46 22 – 4 Seed Plants

47 Objectives Describe the reproductive adaptations of seed plants
Describe the evolution of seed plants Identify the four groups of gymnosperms

48 Over millions of years, plants with a single trait—the ability to form seeds—became the most dominant group of photosynthetic organisms on land. Seed plants are divided into two groups:

49 Gymnosperms Cone plants
Bear their seeds directly on the surfaces of cones Ex.) conifers, pines, spruces, cycads, ancient ginkgoes and gnetophytes

50 Angiosperms Flowering plants
Bear their seeds within a layer of tissue that protects the seed Ex.) grasses, flowering trees shrubs, wild flowers

51 Reproduction Free From Water
Unlike mosses and ferns, however, seed plants do not require water for fertilization of gametes. Q: Why was this an advantage? A: They could live further away from water Adaptations that allow seed plants to reproduce without water include flowers or cones, the transfer of sperm by pollination, and the protection of embryos in seeds.

52 Cones and Flowers

53 Cones Seed bearing structures of gymnosperms

54 Flowers Seed bearing structures of angiosperms

55 Pollen

56 Pollen grain Contains the male gamete


58 Pollination The transfer of pollen from the male gametophyte to the female gametophyte


60 Seeds

61 seed An embryo of a plant that is encased in a protective covering and surrounded by a food supply

62 embryo Early development stage of a sporophyte plant
The seed’s food supply provides nutrients to the embryo as it grows

63 Seed Coat Surrounds and protects the embryo and keeps the contents of the seed from drying out Can be specialized for dispersal



66 Evolution of Seed Plants
Over a period of millions of years, continents became much drier, making it harder for seedless plants to survive and reproduce. For that reason, many moss and fern species became extinct. They were replaced by seed plants with adaptations that equipped them to deal with drier conditions.

67 Gymnosperms—Cone Bearers
The most ancient surviving seed plants are the gymnosperms.   Gymnosperms include:

68 Gnetophytes

69 Cycads

70 Ginkgos


72 Conifers

73 22–5 Angiosperms - Flowering Plants

74 Objectives Identify the characteristics of angiosperms
Explain what monocots and dicots are Describe the three different life spans of angiosperms

75 Flowering plants originated on land and quickly came to dominate Earth’s plant life.
The vast majority of living plant species reproduce with flowers.


77 Flowers and Fruits Angiosperms have unique reproductive organs known as flowers. Q: Why are flowers evolutionary adaptations? A: they attract animals that pollinate them


79 Flowers contain ovaries, which surround and protect the seeds
After pollination, the ovary develops into a fruit, which protects the seed and aids in its dispersal.

80 Fruit Ripened ovary, thick wall of tissue that surrounds the seed

81 Diversity of Angiosperms
The angiosperms are an incredibly diverse group. Not surprisingly, there are many different ways of categorizing these plants.

82 Monocots and Dicots Monocots and dicots are named for the number of seed leaves, or cotyledons, in the plant embryo. Monocots have one seed leaf, and dicots have two seed leafs


84 Woody and Herbaceous Plants
Woody plants – Have woody stems Ex.) trees, shrubs, vines

85 Herbaceous Plants Plant stems that are smooth and nonwoody
Ex.) dandelions, petunias, and sunflowers

86 Annuals, Biennials, and Perennials

87 Annuals Angiosperms that complete a life cycle within one growing season

88 Biennials Angiosperms that complete their life cycle in two years
In the first year, biennials germinate and grow roots, stems, leaves During their second year, biennials grow new stems and leaves and then produce flowers and seeds

89 Perennials Flowering plants that live for more than two years

Download ppt "Chapter 22 Plant Diversity."

Similar presentations

Ads by Google