BIS2C. Biodiversity and the Tree of Life. 2014. L13. Fungi

Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014

Lecture 13

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Lecture 13 !

Fungi !!

BIS 002C Biodiversity & the Tree of Life

Spring 2014 !

Prof. Jonathan Eisen

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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


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


Some practice questions

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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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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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Lecture 22 Outline

• What are Fungi?

• Diversity of form

• Phylogenetic diversity

• Symbioses

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Lecture 22 Outline

• What are Fungi?

• Diversity of form

• Phylogenetic diversity

• Symbioses

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Clicker

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Clicker

• Which of the following groups is least closely related to fungi?

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• A: Animals

• B: Choanoflagellates

• C: Excavates

• D. Opisthokonts

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Clicker

• Which of the following groups is least closely related to fungi?

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• A: Animals

• B: Choanoflagellates

• C: Excavates

• D. Opisthokonts

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Figure 30.1 Fungi in Evolutionary Context

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Predatory Fungi

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Predatory Fungi

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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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Fungal Decomposition

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Fungal Decomposition

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Diversity of Form

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Figure 30.2 Yeasts

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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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Multicellular Fungi: Hyphae Used to Create Structures

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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.


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).


Mushroom growth

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Mushroom growth

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Fungi or Not?

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Phytophthora

Potato Late Blight

• Non-photosynthetic. • Are absorptive heterotrophs

32Sudden Oak Death


Stramenopiles: Oomcyetes

Phytophthora

Potato Late Blight

• Non-photosynthetic. • Are absorptive heterotrophs • Once were classed as fungi, but

are unrelated.

33Sudden Oak Death


• Form spores on stalks called fruiting bodies.

• Found in cool, moist habitats

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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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• 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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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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Fungal reproduction

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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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Figure 30.4 Spores Galore

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Fungal Spores

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Fungal Spores

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Puffballs

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Puffballs

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• 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


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)



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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)



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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


Figure 30.11 A Generalized Fungal Life Cycle

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Phylogeny of Fungi

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Figure 30.2 Phylogeny of the Fungi

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Know what is in this tree


Table 30.1 Classification of fungi

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Table 30.1 Classification of fungi

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Know what is in this table

BIS2C. Biodiversity and the Tree of Life. 2014. L13. Fungi

Science