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Chapter 16 Plants, Fungi, and the Move onto Land

0. Chapter 16 Plants, Fungi, and the Move onto Land. Biology and Society: Will the Blight End the Chestnut?. American chestnut trees Once dominated forests of the eastern United States Were prized for their Rapid growth Huge size Rot-resistant wood

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Chapter 16 Plants, Fungi, and the Move onto Land

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  1. 0 Chapter 16 Plants, Fungi, and the Move onto Land Laura Coronado Bio 10 Chapter 16

  2. Biology and Society: Will the Blight End the Chestnut? • American chestnut trees • Once dominated forests of the eastern United States • Were prized for their • Rapid growth • Huge size • Rot-resistant wood • Around 1900, an Asian fungus was accidentally introduced from China into North America, and in just 25 years, blight caused by the fungus killed virtually all adult American chestnut trees. • Fortunately, this type of harmful interaction between plant and fungus is unusual. • Many plants and fungi benefit from each other’s existence. Laura Coronado Bio 10 Chapter 16

  3. Bacteria Archaea Protists Eukarya Plants Fungi Animals Laura Coronado Bio 10 Chapter 16 Figure 16.UN01

  4. Terrestrial Adaptations of Plants Structural Adaptations • Plants are terrestrial organisms that include forms that have returned to water, such as water lilies. • A plant is • A multicellular eukaryote • A photoautotroph, making organic molecules by photosynthesis • In terrestrial habitats, the resources that a photosynthetic organism needs are found in two very different places: • Light and carbon dioxide are mainly available in the air • Water and mineral nutrients are found mainly in the soil Laura Coronado Bio 10 Chapter 16

  5. Terrestrial Adaptations of Plants Structural Adaptations • The complex bodies of plants are specialized to take advantage of these two environments by having • Aerial leaf-bearing organs called shoots • Subterranean organs called roots • Most plants have mycorrhizae, symbiotic fungi associated with their roots, in which the fungi • Absorb water and essential minerals from the soil • Provide these materials to the plant • Are nourished by sugars produced by the plant Laura Coronado Bio 10 Chapter 16

  6. Reproductive structures (such as those in flowers) contain spores and gametes Plant Leaf performs photosynthesis Cuticle reduces water loss; stomata regulate gas exchange Shoot supports plant (and may perform photosynthesis) Alga Whole alga performs photosynthesis; absorbs water, CO2, and minerals from the water Surrounding water supports the alga Roots anchor plant; absorb water and minerals from the soil (aided by fungi) Laura Coronado Bio 10 Chapter 16 Figure 16.1

  7. Roots Fungus Root surrounded by fungus Laura Coronado Bio 10 Chapter 16 Figure 16.2

  8. Plant Structures • Leaves are the main photosynthetic organs of most plants, with • Stomata for the exchange of carbon dioxide and oxygen with the atmosphere • Vascular tissue for transporting vital materials • A waxy cuticle surface that helps the plant retain water • Vascular tissue in plants is also found in the • Roots • Shoots • Two types of vascular tissue exist in plants: • Xylem transports water and minerals from roots to leaves • Phloem distributes sugars from leaves to the roots and other nonphotosynthetic parts of the plant Laura Coronado Bio 10 Chapter 16

  9. Leaves Gametangia Stomata Cuticle Lignin Shoot Vascular tissues Roots Laura Coronado Bio 10 Chapter 16 Figure 16.UN07

  10. Phloem Vascular tissue Xylem Oak leaf Laura Coronado Bio 10 Chapter 16 Figure 16.3

  11. Reproductive Adaptations • Plants produce their gametes in protective structures called gametangia, which have a jacket of protective cells surrounding a moist chamber where gametes can develop without dehydrating. • The zygote develops into an embryo while still contained within the female parent in plants but not in algae. Laura Coronado Bio 10 Chapter 16

  12. LM Embryo Maternal tissue Laura Coronado Bio 10 Chapter 16 Figure 16.4

  13. The Origin of Plants from Green Algae • The algal ancestors of plants • Carpeted moist fringes of lakes or coastal salt marshes • First evolved over 500 million years ago • Charophytes • Are amodern-day lineage of green algae • May resemble one of these early plant ancestors Laura Coronado Bio 10 Chapter 16

  14. LM LM Laura Coronado Bio 10 Chapter 16 Figure 16.5

  15. PLANT DIVERSITY & EVOLUTION • The history of the plant kingdom is a story of adaptation to diverse terrestrial habitats. • The fossil record chronicles four major periods of plant evolution. • (1) About 475 million years ago plants originated from an algal ancestor giving rise to bryophytes, nonvascular plants, including mosses, liverworts, and hornworts that are nonvascular plants without • Lignified walls • True roots • True leaves Laura Coronado Bio 10 Chapter 16

  16. Charophytes (a group of green algae) Origin of first terrestrial adaptations (about 475 mya) Ancestral green algae Nonvascular plants (bryophytes) Bryophytes Land plants Origin of vascular tissue (about 425 mya) Ferns and other seedless vascular plants Seedless vascular plants Origin of seeds (about 360 mya) Vascular plants Gymnosperms Origin of flowers (about 140 mya) Seed plants Angiosperms 600 500 400 300 200 100 0 Millions of years ago Laura Coronado Bio 10 Chapter 16 Figure 16.6

  17. Bryophytes Ferns Gymnosperms Angiosperms Laura Coronado Bio 10 Chapter 16 Figure 16.UN02

  18. PLANT EVOLUTION • (2) About 425 million years ago ferns evolved • With vascular tissue hardened with lignin • But without seeds • (3) About 360 million years ago gymnosperms evolved with seeds that consisted of an embryo packaged along with a store of food within a protective covering but not enclosed in any specialized chambers. • Today, conifers,consisting mainly of cone-bearing trees such as pines, are the most diverse and widespread gymnosperms. • (4) About 140 million years ago angiosperms evolved with complex reproductive structures called flowers that bear seeds within protective chambers called ovaries. Laura Coronado Bio 10 Chapter 16

  19. Plant Diversity • The great majority of living plants • Are angiosperms • Include fruit and vegetable crops, grains, grasses, and most trees • Are represented by more than 250,000 species Laura Coronado Bio 10 Chapter 16

  20. PLANT DIVERSITY Bryophytes (nonvascular plants) Ferns (seedless vascular plants) Gymnosperms (naked-seed plants) Angiosperms (flowering plants) Laura Coronado Bio 10 Chapter 16 Figure 16.7

  21. Bryophytes • Bryophytes, most commonly mosses • Sprawl as low mats over acres of land • Need water to reproduce because their sperm swim to reach eggs within the female gametangium • Have two key terrestrial adaptations: • A waxy cuticle that helps prevent dehydration • The retention of developing embryos within the mother plant’s gametangium Laura Coronado Bio 10 Chapter 16

  22. Laura Coronado Bio 10 Chapter 16 Figure 16.8

  23. Spores Spore capsule Sporophyte Gametophytes Laura Coronado Bio 10 Chapter 16 Figure 16.9

  24. Mosses • Mosses have two distinct forms: • The gametophyte, which produces gametes • The sporophyte, which produces spores • The life cycle of a moss exhibits an alternation of generations shifting between the gametophyte and sporophyte forms. • Mosses and other bryophytes are unique in having the gametophyte as the larger, more obvious plant. Laura Coronado Bio 10 Chapter 16

  25. Mit osis osis Mit sis o t Mi Gametes: sperm and eggs (n) Spores (n) Gametophyte (n) FERTILIZATION MEIOSIS Spore capsule Zygote (2n) Sporophyte (2n) Key Haploid (n) Diploid (2n) Laura Coronado Bio 10 Chapter 16 Figure 16.10-5

  26. Ferns • Ferns are • Seedless vascular plants • By far the most diverse with more than 12,000 known species • The sperm of ferns, like those of mosses • Have flagella • Must swim through a film of water to fertilize eggs Laura Coronado Bio 10 Chapter 16

  27. Spore capsule “Fiddlehead” (young leaves ready to unfurl) Laura Coronado Bio 10 Chapter 16 Figure 16.11

  28. Carboniferous Period • During the Carboniferous period, from about 360 to 300 million years ago, ferns • Were part of a great diversity of seedless plants • Formed swampy forests over much of what is now Eurasia and North America • As they died, these forests formed coal. • Fossil fuels • Include coal, oil, and natural gas • Formed from the remains of long-dead organisms Laura Coronado Bio 10 Chapter 16

  29. Laura Coronado Bio 10 Chapter 16 Figure 16.12

  30. Gymnosperms • At the end of the Carboniferous period, the climate turned drier and colder, favoring the evolution of gymnosperms, which can • Complete their life cycles on dry land • Withstand long, harsh winters • The descendants of early gymnosperms include the conifers, or cone-bearing plants. Laura Coronado Bio 10 Chapter 16

  31. Conifers • Cover much of northern Eurasia and North America • Are usually evergreens, which retain their leaves throughout the year • Include the tallest, largest, and oldest organisms on Earth Laura Coronado Bio 10 Chapter 16

  32. Terrestrial Adaptations of Seed Plants • Conifers and most other gymnosperms have three additional terrestrial adaptations: • Further reduction of the gametophyte • Pollen • Seeds • Seed plants have a greater development of the diploid sporophyte compared to the haploid gametophyte generation. • A pine tree or other conifer is actually a sporophyte with tiny gametophytes living in cones. Laura Coronado Bio 10 Chapter 16

  33. Gametophyte (n) Sporophyte (2n) Sporophyte (2n) Sporophyte (2n) Gametophyte (n) Gametophyte (n) (a) Sporophyte dependent on gametophyte (e.g., mosses) (b) Large sporophyte and small, Independent gametophyte (e.g., ferns) (c) Reduced gametophyte dependent on sporophyte (seed plants) Key Haploid (n) Diploid (2n) Laura Coronado Bio 10 Chapter 16 Figure 16.14

  34. Scale Ovule-producing cones; the scales contain female gametophytes Pollen-producing cones; they produce male gametophytes Ponderosa pine Laura Coronado Bio 10 Chapter 16 Figure 16.15

  35. Terrestrial Adaptations of Seed Plants • A second adaptation of seed plants to dry land was the evolution of pollen. • A pollen grain • Is actually the much-reduced male gametophyte • Houses cells that will develop into sperm • The third terrestrial adaptation was the development of the seed, consisting of • A plant embryo • A food supply packaged together within a protective coat Laura Coronado Bio 10 Chapter 16

  36. Seeds • Develop from structures called ovules, located on the scales of female cones in conifers • Can remain dormant for long periods before they germinate, as the embryo emerges through the seed coat as a seedling Laura Coronado Bio 10 Chapter 16

  37. Haploid (n) Diploid (2n) Female cone, cross section Cross section of scale Integument Spore case (a) Ovule Spore Egg nucleus Female gametophyte Spore case (b) Fertilized ovule Pollen tube Discharged sperm nucleus Pollen grain (male gametophyte) Seed coat (derived from integument) (c) Seed Food supply (derived from female gametophyte tissue) Embryo (new sporophyte) Laura Coronado Bio 10 Chapter 16 Figure 16.16-3

  38. Angiosperms • Angiosperms • Dominate the modern landscape • Are represented by about 250,000 species • Supply nearly all of our food and much of our fiber for textiles • Their success is largely due to • A more efficient water transport • The evolution of the flower Laura Coronado Bio 10 Chapter 16

  39. Flowers, Fruits, & the Angiosperm Life Cycle • Flowers help to attract pollinators who transfer pollen from the sperm-bearing organs of one flower to the egg-bearing organs of another. • A flower is actually a short stem with four whorls of modified leaves: • Sepals • Petals • Stamens • Carpels • Flowers are an essential element of the angiosperm life cycle & come in many forms Laura Coronado Bio 10 Chapter 16

  40. Petal Stigma Anther Carpel Stamen Style Filament Ovary Ovule Sepal Laura Coronado Bio 10 Chapter 16 Figure 16.17

  41. Pansy Bleeding heart California poppy Water lily Laura Coronado Bio 10 Chapter 16 Figure 16.18

  42. Germinated pollen grain (male gametophyte) on stigma of carpel Anther at tip of stamen Pollen tube growing down style of carpel Mature sporophyte plant with flowers Ovary (base of carpel) Ovule FERTILIZATION Endosperm Embryo sac (female gametophyte) Egg Zygote Two sperm nuclei Sporophyte seedling Embryo (sporophyte) Seed Germinating seed Key Haploid (n) Diploid (2n) Seed (develops from ovule) Fruit (develops from ovary) Laura Coronado Bio 10 Chapter 16 Figure 16.19-6

  43. Seed Types • Although both have seeds • Angiosperms enclose the seed within an ovary • Gymnosperms have naked seeds • Fruit • Is a ripened ovary • Helps protect the seed • Increases seed dispersal • Is a major food source for animals Laura Coronado Bio 10 Chapter 16

  44. Wind dispersal Animal transportation Animal ingestion Laura Coronado Bio 10 Chapter 16 Figure 16.20

  45. Angiosperms and Agriculture • Gymnosperms supply most of our lumber and paper. • Angiosperms • Provide nearly all our food • Supply fiber, medications, perfumes, and decoration • Agriculture is a unique kind of evolutionary relationship between plants and animals. Laura Coronado Bio 10 Chapter 16

  46. Plant Diversity as a Nonrenewable Resource • The exploding human population is • Extinguishing plant species at an unprecedented rate • Destroying fifty million acres, an area the size of the state of Washington, every year! • Humans depend on plants for thousands of products including • Food • Building materials • Medicines Laura Coronado Bio 10 Chapter 16

  47. Laura Coronado Bio 10 Chapter 16 Figure 16.21

  48. Laura Coronado Bio 10 Chapter 16 Table 16.1

  49. Plant Preservation • Preserving plant diversity is important to many ecosystems and humans. • Scientists are now rallying to • Slow the loss of plant diversity • Encourage management practices that use forests as resources without damaging them Laura Coronado Bio 10 Chapter 16

  50. FUNGI • Fungi • Recycle vital chemical elements back to the environment in forms other organisms can assimilate • Form mycorrhizae, fungus-root associations that help plants absorb from the soil • Minerals • Water • Eukaryotes • Typically multicellular • More closely related to animals than plants, arising from a common ancestor about 1.5 billion years ago • Come in many shapes and sizes • Represent more than 100,000 species Laura Coronado Bio 10 Chapter 16

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