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Tobin and Dusheck: Asking About Life, 3E__________ Chapter 22 Copyright 2005 Brooks/Cole Thomson Learning Chapter 22 How Did Plants Adapt to Dry Land?

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Presentation on theme: "Tobin and Dusheck: Asking About Life, 3E__________ Chapter 22 Copyright 2005 Brooks/Cole Thomson Learning Chapter 22 How Did Plants Adapt to Dry Land?"— Presentation transcript:

1 Tobin and Dusheck: Asking About Life, 3E__________ Chapter 22 Copyright 2005 Brooks/Cole Thomson Learning Chapter 22 How Did Plants Adapt to Dry Land?

2 Tobin and Dusheck: Asking About Life, 3E__________ Chapter 22 Copyright 2005 Brooks/Cole Thomson Learning Key Questions How did plants adapt to life on land? How do bryophytes survive on land without vascular tissues? What are the advantages of a vascular system? How are seeds an adaptation to a dry, terrestrial environment? What roles do flowers and fruits play in angiosperm reproduction?

3 Tobin and Dusheck: Asking About Life, 3E__________ Chapter 22 Copyright 2005 Brooks/Cole Thomson Learning What Is a Plant? Multicellular organism that performs photosynthesis and develops from an embryo Almost all live on land Descendants of protists Land invasion depended on evolution of different structures

4 Tobin and Dusheck: Asking About Life, 3E__________ Chapter 22 Copyright 2005 Brooks/Cole Thomson Learning Land Adaptations Waxy cuticle reduces water loss Ability to absorb water from a variety of sources Enclosed reproductive organs, called gametangia, in which gametes form Enclosed sporangia in which spores form

5 Tobin and Dusheck: Asking About Life, 3E__________ Chapter 22 Copyright 2005 Brooks/Cole Thomson Learning Identify Different Plant Types Identify as many different plants as you can. How are they different from one another?

6 Tobin and Dusheck: Asking About Life, 3E__________ Chapter 22 Copyright 2005 Brooks/Cole Thomson Learning Vascular vs. Nonvascular Vascular or tracheophytes Have pipelike tissues that conduct water Grow large Examples: fir trees, ferns Nonvascular or bryophytes Lack a vascular system Much smaller Less diverse

7 Tobin and Dusheck: Asking About Life, 3E__________ Chapter 22 Copyright 2005 Brooks/Cole Thomson Learning The Divisions of Plants

8 Tobin and Dusheck: Asking About Life, 3E__________ Chapter 22 Copyright 2005 Brooks/Cole Thomson Learning Evolution of Plants

9 Tobin and Dusheck: Asking About Life, 3E__________ Chapter 22 Copyright 2005 Brooks/Cole Thomson Learning Plant Evolution Evidence comes from fossils and comparisons with living species First plants evolved from a common ancestor that resembled a green alga Vascular plants predate nonvascular plants First seedless plants Carboniferous Period

10 Tobin and Dusheck: Asking About Life, 3E__________ Chapter 22 Copyright 2005 Brooks/Cole Thomson Learning Kingdom Plantae

11 Tobin and Dusheck: Asking About Life, 3E__________ Chapter 22 Copyright 2005 Brooks/Cole Thomson Learning Angiosperm Evolution Angiosperms flowering plants First fossils about 125 million years ago Evolved from gymnosperms plants that have no fruits or flowers Many adaptations

12 Tobin and Dusheck: Asking About Life, 3E__________ Chapter 22 Copyright 2005 Brooks/Cole Thomson Learning Mosses, Liverworts and Hornworts Nonvascular Plants or bryophytes Depend on free standing water for photosynthesis and fertilization

13 Tobin and Dusheck: Asking About Life, 3E__________ Chapter 22 Copyright 2005 Brooks/Cole Thomson Learning Bryophyte Characteristics All parts of their bodies are adapted to absorb water This gives them a spongy feel Exhibit alternation of generations a sexual life cycle in which haploid and diploid phases are both multicellular

14 Tobin and Dusheck: Asking About Life, 3E__________ Chapter 22 Copyright 2005 Brooks/Cole Thomson Learning Life Cycle of a Moss

15 Tobin and Dusheck: Asking About Life, 3E__________ Chapter 22 Copyright 2005 Brooks/Cole Thomson Learning Vascular Plants

16 Tobin and Dusheck: Asking About Life, 3E__________ Chapter 22 Copyright 2005 Brooks/Cole Thomson Learning Vascular Plants Called tracheophytes Have division of labor with separate transport systems for water (xylem) and sugars (phloem) Diploid Phase dominates the life of the plant Seeds are protected by coat, and food is stored inside for germination

17 Tobin and Dusheck: Asking About Life, 3E__________ Chapter 22 Copyright 2005 Brooks/Cole Thomson Learning Seed-Lacking Tracheophytes 4 divisions that lack seeds: –Pterophytes (ferns) –Psilotophytes –Lycophytes –Equisetophytes

18 Tobin and Dusheck: Asking About Life, 3E__________ Chapter 22 Copyright 2005 Brooks/Cole Thomson Learning Life Cycle of a Fern

19 Tobin and Dusheck: Asking About Life, 3E__________ Chapter 22 Copyright 2005 Brooks/Cole Thomson Learning Life Cycle of a Fern A fern releases haploid spores Spores mature into haploid gametophytes Gametophytes make sperm and egg Fusion of sperm and egg Zygotes grow right out of the gametophyte for a new fern

20 Tobin and Dusheck: Asking About Life, 3E__________ Chapter 22 Copyright 2005 Brooks/Cole Thomson Learning Lycophytes Have true roots, stems and simple leaves Also called lycopods Example: club mosses

21 Tobin and Dusheck: Asking About Life, 3E__________ Chapter 22 Copyright 2005 Brooks/Cole Thomson Learning Equisetophytes Referred to as horsetails Have true roots, stems and complex leaves Stems are jointed Outer cell walls are reinforced with silica

22 Tobin and Dusheck: Asking About Life, 3E__________ Chapter 22 Copyright 2005 Brooks/Cole Thomson Learning Reproduction in Seed Plants Manage fertilization without water Use a form of internal fertilization Sperm and ovum fused, and develop within the female gametophyte Seeds consist of a diploid zygote and a source of food encased in a seed coat

23 Tobin and Dusheck: Asking About Life, 3E__________ Chapter 22 Copyright 2005 Brooks/Cole Thomson Learning Gymnosperms Seed plants without flowers Evergreen Conifers produce male and female gametophytes in cone- shaped strobili (the cones) Male and female cones on same tree

24 Tobin and Dusheck: Asking About Life, 3E__________ Chapter 22 Copyright 2005 Brooks/Cole Thomson Learning Life Cycle of a Pine

25 Tobin and Dusheck: Asking About Life, 3E__________ Chapter 22 Copyright 2005 Brooks/Cole Thomson Learning Cycads Large-leafed plants that look like palms No flowers or fruits Bear naked seeds Produce male and female strobili

26 Tobin and Dusheck: Asking About Life, 3E__________ Chapter 22 Copyright 2005 Brooks/Cole Thomson Learning Ginkgos Either male or female Resemble cycads in their life cycle Resemble conifers in their growth patterns

27 Tobin and Dusheck: Asking About Life, 3E__________ Chapter 22 Copyright 2005 Brooks/Cole Thomson Learning Uses of Flowers and Fruits Flowers ensure distribution of pollen through a variety of methods Fruits are mature ovaries that enclose and protect seeds Fruits usually enhance dispersal of seeds

28 Tobin and Dusheck: Asking About Life, 3E__________ Chapter 22 Copyright 2005 Brooks/Cole Thomson Learning Life Cycle of a Flowering Plant

29 Tobin and Dusheck: Asking About Life, 3E__________ Chapter 22 Copyright 2005 Brooks/Cole Thomson Learning Angiosperm Reproduction Flowers reproduce by means of double fertilization 2 sperm nuclei from the pollen grain fertilize 2 ova from the ovary A diploid zygote is formed and a triploid cell forms the endosperm

30 Tobin and Dusheck: Asking About Life, 3E__________ Chapter 22 Copyright 2005 Brooks/Cole Thomson Learning Flower Parts Stamen anther and filament (male) Carpel style and ovary (female) A corolla or petals and a calyx of sepals surround stamens and carpels Not all flowers have all parts

31 Tobin and Dusheck: Asking About Life, 3E__________ Chapter 22 Copyright 2005 Brooks/Cole Thomson Learning Key Concepts A plant is a multicellular organism that photosynthesizes and develops an embryo Nonvascular plants lack vascular tissues The vascular system enables plants to transport water and nutrients, to grow large, and to diversify Seeds allow plant to withstand dry environments


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