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What is the biggest organism in this Oregonian forest?

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Presentation on theme: "What is the biggest organism in this Oregonian forest?"— Presentation transcript:

1 What is the biggest organism in this Oregonian forest?

2 Hint, it is pictured

3 The honey mushroom fungus

4 Fun-gi vids pig decomposition time-lapse fungus time-lapse growing mold time-lapse parasitic fungi time-lapse

5 LECTURE PRESENTATIONS For CAMPBELL BIOLOGY, NINTH EDITION Jane B. Reece, Lisa A. Urry, Michael L. Cain, Steven A. Wasserman, Peter V. Minorsky, Robert B. Jackson © 2011 Pearson Education, Inc. Lectures by Erin Barley Kathleen Fitzpatrick Fungi Chapter 31

6 Concept 31.1: Fungi are heterotrophs that feed by absorption Fungi are heterotrophs and absorb nutrients from outside of their body Fungi use enzymes to break down a large variety of complex molecules into smaller organic compounds Fungi exhibit diverse lifestyles –Decomposers –rabbit decomposingrabbit decomposing –Parasites –previously shown, with new bonus mushroom and slime mold time-lapsepreviously shown, with new bonus mushroom and slime mold time-lapse –Mutualists © 2011 Pearson Education, Inc.

7 Animation: Fungal Reproduction and Nutrition Right-click slide / select “Play”

8 Anatomy basics Fungi consist of mycelia, networks of branched hyphae adapted for absorption A mycelium’s structure maximizes its surface area-to-volume ratio Fungal cell walls contain chitin © 2011 Pearson Education, Inc.

9 Reproductive structure Hyphae Spore-producing structures Mycelium 60  m Figure 31.2

10 TWO FORMS OF HYPHAE (a) Septate hypha (b) Coenocytic hypha Nuclei Cell wall Pore Septum Nuclei Cell wall

11 1 pinch of soil can contain 1 km of hyphae

12 How much hyphae did she eat?

13 Some unique fungi have specialized hyphae called haustoria that allow them to penetrate the tissues of their host (a) Hyphae adapted for trapping and killing prey (b) Haustoria Fungal hypha Plant cell wall Plant cell Plant cell plasma membrane Haustorium Nematode Hyphae 25  m

14 Mycorrhizae are mutually beneficial relationships between fungi and plant roots, which most vascular plants have –Ectomycorrhizal fungi form sheaths of hyphae over a root and also grow into the extracellular spaces of the root cortex –Arbuscular mycorrhizal fungi extend hyphae through the cell walls of root cells and into tubes formed by invagination of the root cell membrane Which is pictured  ? Which is pictured on the previous slide? © 2011 Pearson Education, Inc.

15 Concept 31.2: Fungi produce spores through sexual or asexual life cycles Fungi propagate themselves by producing vast numbers of spores, either sexually or asexually, or both © 2011 Pearson Education, Inc.

16 Fungi life cycle paths can be funky Key Haploid (n) Heterokaryotic Diploid (2n) Spores Spore-producing structures ASEXUAL REPRODUCTION GERMINATION Mycelium

17 PLASMOGAMY Key Haploid (n) Heterokaryotic Diploid (2n) Spores Spore-producing structures ASEXUAL REPRODUCTION SEXUAL REPRODUCTION GERMINATION Zygote Heterokaryotic stage KARYOGAMY Mycelium Fungi life cycle paths can be funky

18 PLASMOGAMY, based on pheromone compatibility Key Haploid (n) Heterokaryotic Diploid (2n) Spores Spore-producing structures ASEXUAL REPRODUCTION SEXUAL REPRODUCTION GERMINATION MEIOSIS Spores Zygote Heterokaryotic stage KARYOGAMY Mycelium Fungi life cycle paths can be funky

19 © 2011 Pearson Education, Inc.

20 Asexual Reproduction In addition to sexual reproduction, many fungi can reproduce asexually Molds produce haploid spores by mitosis and form visible mycelia © 2011 Pearson Education, Inc.

21 Figure  m Parent cell Bud CHECK-IN Q Yeast are unicellular and reproduce by budding. Then what makes them fungi?

22 DNA evidence suggests that –Fungi are most closely related to unicellular nucleariids –Animals are most closely related to unicellular choanoflagellates Based on this, did fungi and animals split before or after the emergence of multicellularity? © 2011 Pearson Education, Inc. Concept 31.3: The ancestor of fungi was an aquatic, single-celled, flagellated protist

23 The Move to Land If fungi are heterotrophic, how does it make sense that they were among the first land colonizers? © 2011 Pearson Education, Inc.

24 The Move to Land If fungi are eukaryotic, how does it make sense that they were among the first land colonizers? © 2011 Pearson Education, Inc.

25 Concept 31.4: Fungi have radiated into a diverse set of lineages Molecular analyses have helped clarify evolutionary relationships among fungal groups, although areas of uncertainty remain © 2011 Pearson Education, Inc.

26 Figure Chytrids (1,000 species) Zygomycetes (1,000 species) Glomeromycetes (160 species) Ascomycetes (65,000 species) Basidiomycetes (30,000 species) Hyphae 25  m Fungal hypha

27 Chytrids Chytrids (phylum Chytridiomycota) are found in freshwater and terrestrial habitats They can be decomposers, parasites, or mutualists Molecular evidence supports the hypothesis that chytrids diverged early in fungal evolution Chytrids are unique among fungi in having flagellated spores, called zoospores © 2011 Pearson Education, Inc.

28 Video: Allomyces Zoospore Release

29 © 2011 Pearson Education, Inc. Video: Phlyctochytrium Zoospore Release

30 Zygomycetes The zygomycetes (phylum Zygomycota) exhibit great diversity of life histories They include fast-growing molds, parasites, and commensal symbionts The life cycle of black bread mold (Rhizopus stolonifer) is fairly typical of the phylum Its hyphae are coenocytic Asexual sporangia produce haploid spores © 2011 Pearson Education, Inc.

31 Figure 31.UN02 Chytrids Zygomycetes Glomeromycetes Ascomycetes Basidiomycetes

32 Figure Rhizopus growing on bread Flagellum Mating type (  ) Mating type (  ) Gametangia with haploid nuclei Young zygosporangium (heterokaryotic) PLASMOGAMY 100  m 50  m Zygosporangium KARYOGAMY SEXUAL REPRODUCTION Diploid nuclei Key Haploid (n) Diploid (2n) Heterokaryotic (n  n) Sporangium MEIOSIS Dispersal and germination ASEXUAL REPRODUCTION Mycelium Sporangia

33 The zygomycetes are named for their sexually produced zygosporangia Zygosporangia are the site of karyogamy and then meiosis Zygosporangia, which are resistant to freezing and drying, can survive unfavorable conditions Some zygomycetes, such as Pilobolus, can actually “aim” their sporangia toward conditions associated with good food sources © 2011 Pearson Education, Inc.

34 Figure mm Pilobolus aiming its sporangia toward light as that is where edible vegitation would be growing (grass). Grass is eaten, spores spread in feces.

35 Glomeromycetes The glomeromycetes (phylum Glomeromycota) were once considered zygomycetes They are now classified in a separate clade Glomeromycetes form arbuscular mycorrhizae © 2011 Pearson Education, Inc.

36 Figure 31.UN03 Chytrids Zygomycetes Glomeromycetes Ascomycetes Basidiomycetes

37 Figure  m

38 Ascomycetes Ascomycetes (phylum Ascomycota) live in marine, freshwater, and terrestrial habitats Ascomycetes produce sexual spores in saclike asci contained in fruiting bodies called ascocarps Ascomycetes are commonly called sac fungi Ascomycetes vary in size and complexity from unicellular yeasts to elaborate cup fungi and morels © 2011 Pearson Education, Inc.

39 Figure 31.UN04 Chytrids Zygomycetes Glomeromycetes Ascomycetes Basidiomycetes

40 Figure Morchella esculenta, the tasty morel Tuber melanosporum, a truffle

41 Ascomycetes include plant pathogens, decomposers, and symbionts Ascomycetes reproduce asexually by enormous numbers of asexual spores called conidia Conidia are not formed inside sporangia; they are produced asexually at the tips of specialized hyphae called conidiophores Neurospora crassa, a bread mold, is a model organism with a well-studied genome © 2011 Pearson Education, Inc.

42 Conidia; mating type (  ) Mating type (  ) Dispersal Germination ASEXUAL REPRODUCTION Hypha Conidiophore Mycelium Germination Ascocarp Dispersal Asci Mycelia Eight ascospores SEXUAL REPRODUCTION Four haploid nuclei MEIOSIS Diploid nucleus (zygote) KARYOGAMY Dikaryotic hyphae Ascus (dikaryotic) PLASMOGAMY Key Haploid (n) Diploid (2n) Dikaryotic (n  n) Figure 31.17

43 Basidiomycetes Basidomycetes (phylum Basidiomycota) include mushrooms, puffballs, and shelf fungi, mycorrhizae, and plant parasites The phylum is defined by a clublike structure called a basidium, a transient diploid stage in the life cycle The basidiomycetes are also called club fungi Many basidiomycetes are decomposers of wood © 2011 Pearson Education, Inc.

44 Figure 31.UN05 Chytrids Zygomycetes Glomeromycetes Ascomycetes Basidiomycetes

45 Figure Shelf fungi Puffballs emitting spores Maiden veil fungus (Dictyphora)

46 The life cycle of a basidiomycete usually includes a long-lived dikaryotic mycelium In response to environmental stimuli, the mycelium reproduces sexually by producing elaborate fruiting bodies called basidiocarps Mushrooms are examples of basidiocarps The numerous basidia in a basidiocarp are sources of sexual spores called basidiospores © 2011 Pearson Education, Inc.

47 Key Haploid (n) Diploid (2n) Dikaryotic (n  n) Mating type (  ) Mating type (  ) Haploid mycelia SEXUAL REPRODUCTION Dispersal and germination Basidiospores (n) Basidium with four basidiospores Basidium containing four haploid nuclei Basidium Basidiospore 1  m MEIOSIS Diploid nuclei KARYOGAMY Basidia (n  n) Basidiocarp (n  n) Gills lined with basidia Dikaryotic mycelium PLASMOGAMY Figure 31.19

48 Figure Basidiomycetes can produce mushrooms quickly Some species may produce “fairy rings”

49 Imagine a fungi-free world…

50 Concept 31.5: Fungi play key roles in nutrient cycling, ecological interactions, and human welfare Fungi interact with other organisms as decomposers, mutualists, and pathogens © 2011 Pearson Education, Inc.

51 Fungi as Decomposers/Nutrient recylers Fungi are efficient decomposers of organic material including cellulose and lignin Fungi are also used in bioremediation projects © 2011 Pearson Education, Inc.

52 Fungi as Mutualists © 2011 Pearson Education, Inc.

53 Fungus-Plant Mutualisms Mycorrhizae are enormously important in natural ecosystems and agriculture –Plants harbor harmless symbiotic endophytes, fungi that live inside leaves or other plant parts –Endophytes make toxins that deter herbivores and defend against pathogens –Most endophytes are ascomycetes © 2011 Pearson Education, Inc.

54 Figure Endophyte not present; pathogen present (E  P  ) Both endophyte and pathogen present (E  P  ) EPEP EPEP EPEP EPEP Leaf mortality (%) Leaf area damaged (%) RESULTS

55 Fungi- animal symbiosis

56

57 Lichens A lichen is a symbiotic association between a photosynthetic microorganism and a fungus –The photosynthetic component is green algae or cyanobacteria –The fungal component is most often an ascomycete The symbioses are so complete that lichens are given scientific names © 2011 Pearson Education, Inc.

58 Figure A fruticose (shrublike) lichen A foliose (leaflike) lichen Crustose (encrusting) lichens

59 Lichen anatomy Ascocarp of fungus 50  m Fungal hyphae Algal layer Soredia Fungal hyphae Algal cell

60 Lichens are important pioneers on new rock and soil surfaces Lichens may have helped the colonization of land by plants 550–600 million years ago © 2011 Pearson Education, Inc.

61 Fungi as Pathogens About 30% of known fungal species are parasites or pathogens, mostly on or in plants Each year, 10% to 50% of the world’s fruit harvest is lost due to fungi Some fungi that attack food crops are toxic to humans © 2011 Pearson Education, Inc.

62 Figure (a) Corn smut on corn (c) Ergots on rye (b) Tar spot fungus on maple leaves

63 Fungi caused Salem Witch Trials? Ergotism is characterized by gangrene, nervous spasms, burning sensations, hallucinations, and temporary insanity –Ergots contain lysergic acid, the raw material for LSD © 2011 Pearson Education, Inc.

64 Global amphibian populations are down due to fungal infection (mycosis) California Sixty Lake Basin Yellow-legged frogs killed by B. dendrobatidis infection Key Boundary of chytrid spread Lake status in 2009: Frog population extinct Treatment lake: frogs treated with fungicides and released N

65 Practical Uses of Fungi Humans eat many fungi and use others to make cheeses, alcoholic beverages, and bread Some fungi are used to produce antibiotics for the treatment of bacterial infections –For example, the ascomycete Penicillium © 2011 Pearson Education, Inc.

66 Fungal production of antibiotic Zone of inhibited growth Staphylococcus Penicillium

67 Figure 31.UN06 Fungal Phylum Distinguishing Features of Morphology and Life Cycles Chytridiomycota (chytrids) Flagellated spores Zygomycota (zygote fungi) Resistant zygosporangium as sexual stage Glomeromycota (arbuscular mycorrhizal fungi) Arbuscular mycorrhizae formed with plants Ascomycota (ascomycetes, or sac fungi) Sexual spores (ascospores) borne internally in sacs called asci; vast numbers of asexual spores (conidia) produced Basidiomycota (basidiomycetes, or club fungi) Elaborate fruiting body (basidiocarp) containing many basidia that produce sexual spores (basidiospores)

68 Figure 31.UN08

69 Figure 31.UN09

70 Figure 31.UN10


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