BIS2C. Biodiversity and the Tree of Life. 2014. L13. Fungi
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Transcript of BIS2C. Biodiversity and the Tree of Life. 2014. L13. Fungi
Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014
Lecture 13
!
Lecture 13 !
Fungi !!
BIS 002C Biodiversity & the Tree of Life
Spring 2014 !
Prof. Jonathan Eisen
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Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014
Where we are going and where we have been
• Previous Lecture: !12: Symbioses and humans
• Current Lecture: !13: Fungi
• Next Lecture: !14: Fungi
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Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 3
BIS2C Midterm 1: A SectionsApril 21st 3:10pm – 4:00pm
Please arrive early bring the following to the exam:
1. A pen
2. A #2 pencil
3. Photo ID
Freeborn Hall
Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 4
Please arrive early bring the following to the exam:
1. A pen
2. A #2 pencil
3. Photo ID
BIS2C Midterm 1: B SectionsApril 21st 4:10pm – 5:00pm
Freeborn Hall Last Names: A - Sak
!Chemistry 179
Last Names: San - Z
1. Chlamydias a. are never pathogenic to humans. b. live only as parasites of other organisms c. are the sister group to Chlorophytes. d. are mostly chemoautotrophic. e. are the smallest known eukaryotes.
!6
1. Chlamydias a. are never pathogenic to humans. b. live only as parasites of other organisms c. are the sister group to Chlorophytes. d. are mostly chemoautotrophic. e. are the smallest known eukaryotes.
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2. Which of the following is not a major clade of eukaryotes a. Excavates b. Rhizaria c. Brown algae d. Blue-green algae e. Red algae
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2. Which of the following is not a major clade of eukaryotes a. Excavates b. Rhizaria c. Brown algae d. Blue-green algae e. Red algae
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3. Which of the following groups is not known to contain photoautotrophic taxa a. Cyanobacteria b. Diatoms c. Euglenids d. Chlaymdias e. Stramenopiles
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3. Which of the following groups is not known to contain photoautotrophic taxa a. Cyanobacteria b. Diatoms c. Euglenids d. Chlaymdias e. Stramenopiles
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4. Which of the following groups is NOT known to contain multicellular organisms a. Brown algae b. Apicomplexans c. Red algae e. Opisthokonts e. Cellular slime molds
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4. Which of the following groups is NOT known to contain multicellular organisms a. Brown algae b. Apicomplexans c. Red algae e. Opisthokonts e. Cellular slime molds
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Clicker
• Which of the following groups is least closely related to fungi?
!
• A: Animals
• B: Choanoflagellates
• C: Excavates
• D. Opisthokonts
!17
Clicker
• Which of the following groups is least closely related to fungi?
!
• A: Animals
• B: Choanoflagellates
• C: Excavates
• D. Opisthokonts
!18
Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014
Figure 30.1 Fungi in Evolutionary Context
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Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014
30.1 What Is a Fungus?
Fungi digest their food outside their bodies by secreting digestive enzymes to break down large food molecules, then they absorb the breakdown products (absorptive heterotrophy).
Many are saprobes (absorb nutrients from dead organic matter); still others are mutualists.
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Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014
Yeasts
Yeasts: unicellular, free-living fungi.
The term does not refer to a taxonomic group but rather to a lifestyle that has evolved multiple times.
Yeasts live in liquid or moist environments and absorb nutrients directly across cell surfaces (no hyphae).
Yeasts are easy to culture and grow rapidly, making them ideal model eukaryote organisms.
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Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014
Multicellular Fungi: Hyphae Used to Create Structures
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Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014
Multicellular Fungi: Mycelia Made Up of Hyphae
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Hyphae
• Hyphae cell walls have chitin. • Some hyphae have incomplete cross walls or septa, and
are called septate. Hyphae without septa are called coenocytic.
• Hyphae allow high surface area to volume ratio. Aids in absorption but susceptible to drying.
Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014
Multicellular Fungi: Hyphae
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Fruiting Body
Vegetative mycelia
Hyphae are used to create structures such as rhizoids (for anchoring) and fungal “bodies” (known as mycleia).
Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014
Phytophthora
Potato Late Blight
• Non-photosynthetic. • Are absorptive heterotrophs
32Sudden Oak Death
Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014
Stramenopiles: Oomcyetes
Phytophthora
Potato Late Blight
• Non-photosynthetic. • Are absorptive heterotrophs • Once were classed as fungi, but
are unrelated.
33Sudden Oak Death
Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014
• Form spores on stalks called fruiting bodies.
• Found in cool, moist habitats
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Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014
Amoebozoans: Plasmodial Slime Molds
• Individual motile cells can form single, multinucleate cell (plasmodium)
• Ingest food by endocytosis • Form spores on stalks called fruiting
bodies. • Found in cool, moist habitats
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Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014
• Elaborate branching
• Some reproduce by forming chains of spores at tips of filaments
• Most antibiotics are from this group
• Causative agents of many diseases
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Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014
High-GC Gram Positives (Actinobacteria)
• High G+C/A+T ratio in DNA
• Elaborate branching
• Some reproduce by forming chains of spores at tips of filaments
• Most antibiotics are from this group
• Causative agents of many diseases such as tuberculosis and leprosy
• Many originally misclassified as fungi
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Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014
Fungal reproduction
If food runs short, one strategy is to reproduce fast. Fungi produce huge quantities of spores, especially if nutrients are low. Spores remain dormant or disperse to new areas. Spores are tiny and easily blown by the wind. Wide dispersal ensures at least some will find favorable conditions.
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Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014
• Asexual reproduction in fungi: !Production of haploid spores in sporangia !Production of haploid spores (conidia) at hyphae tips !Cell division by unicellular fungi—fission or budding !Breakage of the mycelium
• Sexual reproduction !Rare or unknown in some groups, common in others. !Fungi have no male/female distinctions or structures. !Mating types are genetically different but not
physically different. !There may be two or more mating types. ! Individuals of the same type cannot mate, avoiding
self-fertilization.43
Fungal reproduction
Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014
Figure 11.15 Fertilization and Meiosis Alternate in Sexual Reproduction (Part 2)
FertilizationHAPLOID (n)
DIPLOID (2n)
Gametophyte (n)
Spores (n) Gametes Male (n) Female (n)
Zygote (2n)
Alteration of generations
Meiosis
Sporophyte (2n)
Fern (Humata tyermanii) (diploid sporophyte)
Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014
Figure 11.15 Fertilization and Meiosis Alternate in Sexual Reproduction (Part 3)
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Gametes Male (n) Female (n)
Meiosis Fertilization
HAPLOID (n)
DIPLOID (2n)
Zygote (2n)
Mature organism (2n)
Diplontic life cycle
Elephant (Loxodonta africana) (diploid organism)
Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014
Figure 11.15 Fertilization and Meiosis Alternate in Sexual Reproduction (Part 1)
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Fungus (Rhizopus oligosporus) (haploid organism)
Meiosis Fertilization
HAPLOID (n)
DIPLOID (2n)
Mature organism (n)
Spores (n) Gametes Male (n) Female (n)
Zygote (2n)
Haplontic life cycle
Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014
Figure 30.11 A Generalized Fungal Life Cycle
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Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014
Figure 30.2 Phylogeny of the Fungi
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Know what is in this tree