18 Lecture Ppt


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Fungi and Plants

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18 Lecture Ppt

  1. 1. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chapter 18 Evolution of Plants and Fungi
  2. 2. The Evolution of Plants Spans 500 Million Years 18-
  3. 3. 18.1 Evidence suggests that plants evolved from green algae <ul><li>Plants - multicellular, photosynthetic eukaryotes that range in size from the duckweed to the giant coastal redwoods </li></ul><ul><ul><li>Important ecologically, industrially, and medically </li></ul></ul><ul><li>Believed to have evolved from freshwater green algae over 500 million years ago </li></ul><ul><ul><li>Evidence - Both green algae and plants </li></ul></ul><ul><ul><ul><li>Contain chlorophylls a and b and various accessory pigments </li></ul></ul></ul><ul><ul><ul><li>Store excess carbohydrates as starch </li></ul></ul></ul><ul><ul><ul><li>Have cellulose in their cell wall </li></ul></ul></ul>18-
  4. 4. Figure 18.1 Close algal relatives of plants 18-
  5. 5. 18.2 The evolution of plants is marked by four innovations <ul><li>Nourish and protect a multicellular embryo that completes the life cycle </li></ul><ul><li>Have vascular tissue transporting water and solute to cells when the plant body is surrounded by air </li></ul><ul><li>Produce seeds that contain an embryo and stored organic nutrients within a protective coat </li></ul><ul><li>Flowers that attract pollinators, such as insects, and give rise to fruits, food for animals to help disperse the seeds </li></ul>18-
  6. 6. Figure 18.2A Representatives of the four major groups of plants 18-
  7. 7. Figure 18.2B Evolutionary history of plants 18-
  8. 8. 18-
  9. 9. 18.3 Plants have an alternation of generations life cycle <ul><li>Alternation of Generations </li></ul><ul><li>A sporophyte represents the diploid generation and a gametophyte represents the haploid generation </li></ul><ul><ul><li>Sporophyte (2n) produces spores by meiosis </li></ul></ul><ul><ul><ul><li>A spore is a haploid reproductive cell that develops into a new organism without needing to fuse with another reproductive cell </li></ul></ul></ul><ul><ul><ul><li>A spore undergoes mitosis to become a gametophyte </li></ul></ul></ul><ul><ul><li>Gametophyte (n) produces gametes </li></ul></ul><ul><ul><ul><li>In plants, eggs and sperm are produced by mitosis </li></ul></ul></ul><ul><ul><ul><li>A sperm and egg fuse, forming a diploid zygote that undergoes mitosis and becomes the sporophyte </li></ul></ul></ul>18-
  10. 10. Figure 18.3 Alternation of generations 18-
  11. 11. 18.4 Sporophyte dominance was adaptive to a dry land environment <ul><li>Reproductive Adaptation to the Land Environment </li></ul><ul><li>Sporophyte dominance can be associated with an increasing adaptation for reproduction in a dry, terrestrial environment </li></ul><ul><li>Ferns are seedless vascular plants with a dominant sporophyte </li></ul><ul><ul><li>The sporophyte produces spores that disperse (scatter) separate gametophytes </li></ul></ul><ul><ul><li>The gametophyte is a small, heart-shaped structure that has no vascular tissue and can dry out if the environment is not moist </li></ul></ul><ul><ul><li>Each archegonium on the surface of a gametophyte produces an egg that is fertilized by a flagellated sperm , which must swim to the archegonium in a film of external water </li></ul></ul><ul><li>Other Adaptations to the Land Environment </li></ul><ul><ul><li>Cuticle - relatively impermeable layer and provides an effective barrier to water loss, but it also limits gas exchange </li></ul></ul><ul><ul><ul><li>Leaves have little openings called stomata (sing., stoma ) that let carbon dioxide enter while allowing oxygen and water to exit </li></ul></ul></ul>18-
  12. 12. Figure 18.4A Reduction in the size of the gametophyte as sporophyte becomes dominant 18-
  13. 13. Flowering plants are seed plants with a dominant sporophyte <ul><li>In flowering plants: </li></ul><ul><ul><li>Sporophyte produces seeds that disperse separate sporophytes protected by seed coats </li></ul></ul><ul><ul><li>Female gametophyte is microscopic and retained and protected within an ovule , a structure located within the tissue of a flower </li></ul></ul><ul><ul><li>The male gametophytes are pollen grains that are transported by wind, insects, or birds </li></ul></ul><ul><ul><ul><li>They do not need external water to reach the egg </li></ul></ul></ul>18-
  14. 14. Figure 18.4B Protection of eggs and embryos 18-
  15. 15. Figure 18.4C Features of the leaves of vascular plants 18-
  16. 16. Plants Are Adapted to the Land Environment 18-
  17. 17. 18.5 Bryophytes are nonvascular plants in which the gametophyte is dominant <ul><li>Nonvascular plants lack a specialized means of transporting water and organic nutrients </li></ul><ul><ul><li>They do not have true roots, stems, and leaves </li></ul></ul><ul><li>bryophyte (lowercase b ) - general term for nonvascular plants </li></ul><ul><li>The Generations of Bryophytes </li></ul><ul><ul><li>Gametophyte is the dominant generation </li></ul></ul><ul><ul><li>Female gametophyte produces eggs in archegonia, and the male gametophyte produces flagellated sperm in antheridia </li></ul></ul><ul><ul><li>Sperm swim to the vicinity of the egg in a continuous film of water </li></ul></ul><ul><ul><li>Zygote becomes a sporophyte embryo that is protected from drying out within the archegonium </li></ul></ul><ul><li>The lack of vascular tissue and the need for sperm to swim to archegonia in a film of water largely account for the limited their height </li></ul>18-
  18. 18. Figure 18.5A Representative bryophytes 18-
  19. 19. Figure 18.5B Moss life cycle, Polytrichum sp 18-
  20. 20. 18.6 Ferns and their allies have a dominant vascular sporophyte <ul><li>Today’s seedless vascular plants </li></ul><ul><ul><li>Club mosses, horsetails and ferns </li></ul></ul><ul><li>Ferns (phylum Pterophyta) include approximately 11,000 species </li></ul><ul><ul><li>Ferns are most abundant in warm, moist, tropical regions, but can also be found in temperate regions </li></ul></ul><ul><ul><li>Range in size from less than 1 cm to giant tropical tree ferns that exceed 20 m </li></ul></ul><ul><ul><li>Large leaves of ferns, called fronds, are commonly divided into leaflets </li></ul></ul><ul><li>Economic Value of Ferns </li></ul><ul><ul><li>Often used by florists in decorative bouquets and as ornamental plants in the home and garden </li></ul></ul>18-
  21. 21. Figure 18.6A Sporophyte of a club moss 18-
  22. 22. Figure 18.6B Diversity of fern fronds 18-
  23. 23. Figure 18.6C Fern life cycle 18-
  24. 24. 18.7 Most gymnosperms bear cones on which the seeds are “naked” <ul><li>Diversity of Gymnosperms </li></ul><ul><ul><li>Four groups of living gymnosperms: cycads, ginkgoes, gnetophytes , and conifers </li></ul></ul><ul><ul><li>All of these plants have ovules and subsequently develop seeds that are exposed on the surface of cone scales or analogous structures </li></ul></ul><ul><li>Conifers (phylum Coniferophyta) </li></ul><ul><ul><li>Consist of about 575 species of trees </li></ul></ul><ul><ul><ul><li>Many are evergreens such as pines, spruces, firs, cedars and hemlocks </li></ul></ul></ul><ul><ul><li>Economic Value of Conifers </li></ul></ul><ul><ul><ul><li>Wood of conifers is used extensively in construction </li></ul></ul></ul>18-
  25. 25. Figure 18.7A Gymnosperm diversity 18-
  26. 26. Figure 18.7B Pine life cycle 18-
  27. 27. APPLYING THE CONCEPTS—HOW BIOLOGY IMPACTS OUR LIVES 18.8 Carboniferous forests became the coal we use today <ul><li>Our industrial society runs on fossil fuels, such as coal </li></ul><ul><li>During Carboniferous period (>300 MYA) a great swamp forest encompassed much of Northern Hemisphere </li></ul><ul><ul><li>Enormous amount of biomass </li></ul></ul><ul><ul><li>Didn’t decay when trees fell in the water </li></ul></ul><ul><ul><li>Remains became covered by sediment that changed to sedimentary rock </li></ul></ul><ul><ul><li>With pressure, and the organic material became coal </li></ul></ul>18-
  28. 28. Figure 18.8 Swamp forest of the Carboniferous period 18-
  29. 29. 18.9 Angiosperms are the flowering plants <ul><li>Angiosperms (phylum Anthophyta) </li></ul><ul><ul><li>240,000 known species </li></ul></ul><ul><ul><li>Evolved at beginning of the Cenozoic era (65 MYA) when the first flying insects appeared </li></ul></ul><ul><ul><ul><li>Flower and their pollinators evolved together </li></ul></ul></ul><ul><ul><li>Flower involved in pollination </li></ul></ul><ul><ul><li>Fruit serves as a means of seed dispersal </li></ul></ul><ul><li>Angiosperm Diversity </li></ul><ul><ul><li>Monocotyledones (or monocots ) </li></ul></ul><ul><ul><ul><li>about 65,000 species </li></ul></ul></ul><ul><ul><li>Eudicotyledones (or eudicots ) </li></ul></ul><ul><ul><ul><li>about 175,000 species </li></ul></ul></ul><ul><li>Cotyledons - seed leaves with nutrients that nourish the embryo </li></ul>18-
  30. 30. Figure 18.9 Generalized flower 18-
  31. 31. 18.10 The flowers of angiosperms produce “covered” seeds <ul><li>Fruits </li></ul><ul><ul><li>Fruits of flowers protect and aid in seed dispersal </li></ul></ul><ul><ul><ul><li>Seeds are transported by wind, gravity, water, or animals to another location </li></ul></ul></ul><ul><ul><li>Fleshy fruits may be eaten by animals, which transport the seeds to a new location and then deposit them when they defecate </li></ul></ul><ul><li>Flowers and Diversification </li></ul><ul><ul><li>Today there are 240,000 species of flowering plants and 700,000 species of insects </li></ul></ul><ul><ul><li>Suggests that success of angiosperms has contributed to the success of insects, and vice versa </li></ul></ul>18-
  32. 32. Figure 18.10 Flowering plant life cycle 18-
  33. 33. Figure 18.10 Flowering plant life cycle (continued) 18-
  34. 34. APPLYING THE CONCEPTS—HOW BIOLOGY IMPACTS OUR LIVES 18.11 Flowering plants provide many services <ul><li>Humans derive most of their sustenance from three flowering plants </li></ul><ul><ul><li>Wheat </li></ul></ul><ul><ul><ul><li>First cultivated in the Middle East about 8000 B.C. thought to be one of the earliest cultivated plants </li></ul></ul></ul><ul><ul><li>Corn </li></ul></ul><ul><ul><ul><li>Properly called maize, first cultivated in Central America about 7,000 years ago </li></ul></ul></ul><ul><ul><li>Rice </li></ul></ul><ul><ul><ul><li>Originated several thousand years ago in southeastern Asia, where it grew in swamps </li></ul></ul></ul><ul><li>Used for centuries for many important items </li></ul><ul><ul><li>Lumber - major part of buildings (mainly comes from conifers) </li></ul></ul><ul><ul><li>Rubber - first made from the thick sap (latex) of the rubber tree </li></ul></ul><ul><ul><li>About 50% of all pharmaceuticals come from plants </li></ul></ul>18-
  35. 35. Figure 18.11A Some species of grain 18-
  36. 36. Figure 18.11B Uses of plants 18-
  37. 37. Fungi Have Their Own Evolutionary History 18-
  38. 38. 18.12 Fungi differ from plants and animals <ul><li>Fungi (domain Eukarya , kingdom Fungi ) </li></ul><ul><ul><li>Structurally diverse group of eukaryotes </li></ul></ul><ul><ul><ul><li>Strict heterotrophs that release digestive enzymes into the external environment and digest their food outside the body </li></ul></ul></ul><ul><ul><li>Mycelium - fungus body, a mass of filaments called hyphae </li></ul></ul><ul><li>Fungal cells are different from plant cells </li></ul><ul><ul><li>Lack chloroplasts and their cell wall contains chitin rather than cellulose </li></ul></ul><ul><li>Fungi are adapted to life on land by producing windblown spores during both asexual and sexual reproduction </li></ul>18-
  39. 39. Figure 18.12A Fungal mycelia and hyphae 18-
  40. 40. 18.13 Fungi have mutualistic relationships with algae and plants <ul><li>In a mutualistic relationship, two different species live together and help each other out </li></ul><ul><ul><li>Lichen - a mutualistic association between a particular fungus and a cyanobacteria or green algae </li></ul></ul><ul><ul><ul><li>Three varieties </li></ul></ul></ul><ul><ul><ul><ul><li>Compact crustose lichens seen on bare rock </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Shrublike fruticose lichens </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Leaflike foliose lichens </li></ul></ul></ul></ul><ul><ul><li>Mycorrhizal fungi form mutualistic relationships with the roots of most plants </li></ul></ul><ul><ul><ul><li>Helps plants grow more successfully in dry or poor soils particularly those deficient in inorganic nutrients </li></ul></ul></ul>18-
  41. 41. 18.14 Fungi occur in three main groups <ul><li>Zygospore Fungi (phylum Zygomycota) </li></ul><ul><ul><li>Mainly saprotrophs, but some parasitize small protists, worms, and even insects </li></ul></ul><ul><li>Sac Fungi (phylum Ascomycota) </li></ul><ul><ul><li>Nearly 75% of all described fungal species </li></ul></ul><ul><ul><li>Yeasts - unicellular forms mainly in Ascomycota </li></ul></ul><ul><li>Club Fungi (phylum Basidiomycota) </li></ul><ul><ul><li>Name comes from the reproductive structure, the basidium (pl., basidia) </li></ul></ul><ul><ul><li>The basidia are located within a basidiocarp </li></ul></ul><ul><ul><ul><li>When you eat a mushroom, you are eating a basidiocarp </li></ul></ul></ul>18-
  42. 42. Figure 18.14A Black bread mold, Rhizopus stolonifer 18-
  43. 43. Figure 18.14B Sexual reproduction in sac fungi 18-
  44. 44. Figure 18.14C Asexual reproductive structures in sac fungi 18-
  45. 45. Figure 18.14D Sexual reproduction in club fungi involves a basidiocarp of which three types are shown 18-
  46. 46. APPLYING THE CONCEPTS—HOW BIOLOGY IMPACTS OUR LIVES 18.15 Fungi have economic and medical importance <ul><li>Economic Importance </li></ul><ul><ul><li>Help produce medicines and many foods </li></ul></ul><ul><ul><ul><li>Mold Penicillium was original source of penicillin </li></ul></ul></ul><ul><ul><li>In U.S., 1.13 billion pounds of mushrooms consumed annually </li></ul></ul><ul><ul><li>Fungal pathogens are a major concern for farmers </li></ul></ul><ul><li>Medical Importance </li></ul><ul><ul><li>Mycoses are diseases caused by fungi </li></ul></ul><ul><ul><li>Tineas are infections of the skin caused by fungi </li></ul></ul><ul><ul><ul><li>Ringworm is a cutaneous infection contracted from soil </li></ul></ul></ul><ul><ul><ul><li>Athlete’s foot is a tinea that affects the skin between the toes </li></ul></ul></ul>18-
  47. 47. Connecting the Concepts: Chapter 18 <ul><li>Both plants and fungi are multicellular organisms adapted to living on land </li></ul><ul><ul><li>Four plant adaptations to a dry environment </li></ul></ul><ul><ul><ul><li>Protect the sporophyte embryo from drying out </li></ul></ul></ul><ul><ul><ul><li>Vascular tissue transports water and solutes </li></ul></ul></ul><ul><ul><ul><li>Seeds allow the sporophyte to be dispersed </li></ul></ul></ul><ul><ul><ul><li>Flowers get animals to pollinate and disperse seeds </li></ul></ul></ul><ul><ul><li>Fungi are adapted to the land environment </li></ul></ul><ul><ul><ul><li>Produce windblown spores for asexual and sexual life cycles </li></ul></ul></ul><ul><ul><ul><li>Saprotrophic and release enzymes into the environment to digest organic remains and absorb nutrients </li></ul></ul></ul><ul><li>Without photosynthesis from algae and plants and decomposition from bacteria and fungi, animals could not exist </li></ul><ul><ul><li>Animals are not essential to the biosphere, but plants and fungi are </li></ul></ul>18-