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Science Starter

Section 22-1. Go to Section:. Science Starter Life as we know it today could not exist without plants. Plants provide us with many essential items other than food. 1. With your partner, list five items you use daily that are byproducts of plants. Section Outline. Section 22-1.

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Science Starter

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  1. Section 22-1 Go to Section: • Science Starter • Life as we know it today could not exist without plants.Plants provide us with many essential items other than food. • 1. With your partner, list five items you use daily that are byproducts of plants.

  2. Section Outline Section 22-1 Go to Section: • 22–1 Introduction to Plants A. What Is a Plant? B. The Plant Life Cycle C. What Plants Need to Survive 1. Sunlight 2. Water and Minerals 3. Gas Exchange 4. Movement of Water and Nutrients D. Early Plants 1. Origins in the Water 2. The First Plants E. Overview of the Plant Kingdom

  3. What is a plant? • What do we already know about plants? • How many cells? • Eukaryote or prokaryote? • How do they get food? • Special structures in cells?

  4. What is a plant? Plants are multicellular eukaryotes that have cell walls, made of cellulose. They develop from multicellular embryos Carry out photosynthesis using green pigment called chlorophyll. They are autotrophs Examples:

  5. What is a plant? “Stationary animals that eat sunlight!” Differences between plants and animals:

  6. The Plant Life Cycle • Two generations: • The haploid (N) gametophyte, or gamete-producing plant • The diploid (2N) sporophyte, or spore-producing plant • Spores are reproductive cells that produce a new individual by mitosis. • This may differ dramatically from phylum to phylum!

  7. MEIOSIS Haploid Diploid FERTILIZATION Generalized Plant Life Cycle Section 22-1 Spores(N) Gametophyte Plant (N) Sporophyte Plant (2N) Sperm(N) Eggs(N) Go to Section:

  8. What Plants Need to Survive • Sunlight • To carry out photosynthesis • Typically photosynthetic organs such as leaves are broad and flat to maximize light absorption. • Water and Minerals • Water also needed for photosynthesis • Minerals can only be taken in through water • Adaptations to limit water loss

  9. What Plants Need to Survive • Gas Exchange • Oxygen needed to support respiration • Carbon dioxide needed for photosynthesis • The problem: Exchange these gasses without losing a lot of water • Movement of Water and Nutrients • Absorption happens at roots, but must move throughout entire plant • Specialized tissues • OR • Diffusion

  10. Early Plants • Read p. 553 first two paragraphs! • Origins in the Water: • The first plants evolved from an organism much like the multicellular green algae living today • The First Plants: • Read paragraph 2 on page 554

  11. Floweringplants Cone-bearingplants Ferns andtheir relatives Flowers; SeedsEnclosed in Fruit Mosses andtheir relatives Seeds Water-Conducting(Vascular) Tissue Green algaeancestor Timeline of Plant evolution Section 22-1 Go to Section:

  12. Overview of the Plant Kingdom • Divided into FOUR groups, based on three important features: fig. 22-7 • 1. water-conduction tissues • 2. seeds • 3. flowers

  13. Figure 22-7 The Diversity of Plants Section 22-1 Cone-bearing plants760 species Floweringplants235,000 species Ferns andtheir relatives11,000 species Mosses andtheir relatives15,600 species Go to Section:

  14. Section Outline Section 22-2 Go to Section: • 22–2 Bryophytes A. Groups of Bryophytes 1. Mosses 2. Liverworts 3. Hornworts B. Life Cycle of Bryophytes 1. Dependence on Water 2. Life Cycle of a Moss C. Human Use of Mosses

  15. Byrophytes • Byrophytes • AKA nonvascular plants • Do not have vascular tissues (tissue that are responsible for conducting water and nutrients) • Have a life cycle that depend on water for reproduction. • Draw up water by osmosis • Can only be a few centimeters off the ground • Example: Mosses

  16. Groups of Bryophytes • Characteristics: • Must be low growing • Usually found in shaded or moist areas • Include: • Mosses • Liverwarts • Hornwarts

  17. Mosses • Most common bryophyte • Belong to phylum Bryophyta • Grow near water • Do not have true roots, instead they have: • Rhizoids: long thin cells that anchor plant into the ground, helps to absorb water and minerals from surrounding soil

  18. Capsule Sporophyte Stalk Stemlikestructure Gametophyte Leaflikestructure The Structure of a Moss Section 22-2 Rhizoid Go to Section:

  19. Liverwarts • Looks like a flat leaf, attached to the ground (shaped like a liver) • Phylum: hepaticophyta • Reproduce asexually by gemmae • Small multicellular spheres that contain haploid cells. • These cells are washed off the parent plant, and they then begin a new plant

  20. Life Cycle of Bryophytes The gametophyte is the dominane, recognazible stage of the life cycle, and it’s the stage that carries out most of the plant’s photosynthesis For fertilization to occur, there must be WATER!

  21. Life Cycle of a Moss Read page #558 Protonema: after a BRYO reporduces, it germinates and begins a tangles mass of green filimants Antheridia: part of BRYO where sperm are produced Archegonia: part of BRYO where the egg is produced

  22. Protonema(young gametophyte)(N) Spores(N) Malegametophyte Femalegametophyte Maturesporophyte(2N) Capsule(sporangium) Antheridia Sperm(N) Archegonia Gametophyte(N) Youngsporophyte(2N) Zygote(2N) Sperm(N) Gametophyte(N) Egg(N) Life Cycle of a Moss Haploid (N) Diploid (2N) MEIOSIS FERTILIZATION Go to Section:

  23. Section Outline Section 22-3 Go to Section: • 22–3 Seedless Vascular Plants A. Evolution of Vascular Tissue B. Ferns and Their Relatives 1. Club Mosses 2. Horsetails 3. Ferns C. Life Cycle of Ferns

  24. Seedless Vascular Plants • Vascular tissues: specialized tissue used to conduct water and nutrients through the body of the plant. • These types of plants can grow taller • Were byrophytes vascular or nonvascular plants?

  25. Evolution of Vascular Tissue • Two types of Vascular Tissue: • Xylem: conducts water upwards from roots to every part of thee plant • Phloem: transports nutrient solutions • Both of these can work against the force of gravity. • Vascular plants produce lignin the substance that make cell wall rigid. • Lignin allows vascular plants to grow upright and reach great heights.

  26. Ferns & their Relatives • Seedless vascular plants include mosses, horsetails and ferns. • These all have true: • Roots: underground organs that absorb water and minerals. • Leaves: contain bundles of vascular tissues, photosynthesis is carried out here. • Veins: composed of xylem and phloem • Stems: supporting structures that connect roots and leaves. Carry water and nutrients between them.

  27. Ferns • More than 11,000 species of ferns • Evolved over 350 million years ago. • Page #562 diagram of a fern • The large leaves = Fronds • Rhizomes: creeping under ground stems

  28. Life Cycle of a Fern Ferns and other vascular plants have a life cycle in which the diploid sporophyte is the dominant life stage.

  29.   The Life Cycle of a Fern Section 22-3 MEIOSIS Sporangium(2N) Haploid gametophyte (N) Diploid sporophyte (2N) Frond Younggametophyte(N) Spores(N) Maturesporophyte(2N) Developingsporophyte(2N) Maturegametophyte(N) Antheridium Sperm Gametophyte(N) Egg Sporophyteembryo(2N) Archegonium FERTILIZATION Go to Section:

  30. Section Outline Section 22-4 Go to Section: • 22–4 Seed Plants A. Reproduction Free From Water 1. Cones and Flowers 2. Pollen 3. Seeds B. Evolution of Seed Plants C. Gymnosperms—Cone Bearers 1. Gnetophytes 2. Cycads 3. Ginkgoes 4. Conifers 5. Ecology of Conifers

  31. Seed Plants • Seed Plants are divided into two groups: • Gymnosperms: bear their seed directly on the surfaces of cones • Examples: Conifers (pine and spruce trees) • Angiosperms: (AKA flowering plants) bear their seeds within a layer of tissue that protects the seed. • Examples: grasses, flowering trees, shrubs, wildflower

  32. Reproduction Free From Water • Still have alternating life cycle b/t gamete and sporophyte stages. • Seed plants DON’T need water to reproduce! • This means seed plants can live about anywhere • 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.

  33. Reproduction free from Water • Seed plants do not require water for fertilization. • Adaptations that allow this include: • Flowers or cones • Transfer of sperm by pollination • Protection of embryos in seeds

  34. Cones and Flowers Cones: seed-bearing structures of gymnosperms Flowers: seed-bearing structure of angiosperms.

  35. Pollen • The entire male gametophyte is contained in a tiny structure called pollen grain. • This PG is carried to the female gametophyte by wind, insects, birds, etc. • This transfer of pollen from the male to the felmale gametophyte is pollination

  36. Seeds Seed: embryo of a plant, encased in a protective covering and surrounded by a food supply. After fertilization the zygote contained with in the seed grows into a tiny plante called the embryo.

  37. Seed coat Seed Embryo Wing Storedfood supply  The Structure of a Seed Section 22-4 • The embryo the early developmental stage of the sporophyte The seed coast surrounds and protects the embryo and keeps it from drying out! B A Go to Section:

  38. Gymnosperms • Read Evolution of Seed plants p. 566 • Gymnosperms • Reproduce with seeds that are exposed • Means “naked seed” • Conifers are most common in our area • Pine, spruce, cedars, redwoods, etc. • Ginkgoes – read p. 567

  39. Science Starter Section 22-4 Comparing Features of Seed Plants Feature Seeds Reproduction Examples Gymnosperms Angiosperms Go to Section:

  40. Science Starter Section 22-4 Comparing Features of Seed Plants Feature Seeds Reproduction Examples Gymnosperms Angiosperms Bear their seeds on cones Can reproduce without water; male gametophytes are contained in pollen grains; fertilization occurs by pollination Conifers, cycads, ginkgoes, gnetophytes Bear their seeds within flowers Can reproduce without water; male gametophytes are contained in pollen grains; fertilization occurs by pollination Grasses, flowering trees and shrubs, wildflowers, cultivated flowers Go to Section:

  41. Section Outline Section 22-5 Go to Section: • 22–5 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

  42. Angiosperms – Flowering Plants • Flowering plants originated on land and quickly came to dominate life • Angiosperms have reproductive organs known as flowers. • Evolutionary advantage – transport of pollen • More efficient than wind pollination of GSperm • Asperms contain ovaries, witch surronund and protect the seed • Asperm actually means “enclosed seed”

  43. Angiosperms – Flowering Plants • Figure 22-24 page 569 • Fruit: a thick wall of tissue surrounding the enclosed seed. • Animals spread the seed by eating fruit and “depositing” seed at another location • Another evolutionary advantage!

  44. Classification of Angiosperms • Classification by 3 groups • These groups can overlap • Monocots and dicots • Woody and herbaceous • Life cycle

  45. Monocots vs. Dicots Monocotyledonae Dicotyledonae Figure 22-25 page 570

  46. Single cotyledon Two cotyledons Parallel veins Branched veins Floral parts often in multiples of 3 Floral parts often in multiplesof 4 or 5 Vascularbundlesscattered throughout stem Vascularbundlesarranged ina ring Fibrous roots Taproot Dicot vs. Monocot Section 22-5 Monocots Dicots Seeds Leaves Flowers Stems Roots Go to Section:

  47. Woody and Herbaceous Plants • Based on stem characteristics • Woody plants: thick cell walls that support plant. • Trees & shrubs • Herbaceous plants: must be smooth and nonwoody. • Dandelions, petunias, sunflowers, geraniums

  48. Life Cycles • 3 groups based on length of time • Read page 572 • Annuals: plants that complete life cycle in one year • EX: marigolds, petunias, zinnias • Biennial: Year one grow and generate roots. Year two produce flowers and seeds, then die • Parsley, celery and foxglove • Perennial: Live for many years.

  49. Annuals Perennials 2 years Science Starter Section 22-5 Plants are categorized as that completetheir life cycle in that completetheir life cycle in that completetheir life cycle in Go to Section:

  50. Annuals Perennials Biennials 1 growingseason More than2 years 2 years Science Starter Section 22-5 Plants are categorized as that completetheir life cycle in that completetheir life cycle in that completetheir life cycle in Go to Section:

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