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
1

Where we are going and where we have been
• Previous Lecture:
!12: Symbioses and humans
• Current Lecture:
!13: Fungi
• Next Lecture:
!14: Fungi
2

Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 3
BIS2C Midterm 1: A Sections 
April 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 Sections 
April 21st 4:10pm – 5:00pm 
Freeborn Hall
Last Names: A - Sak
!
Chemistry 179
Last Names: San - Z

Some practice questions
5

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.
!7

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
!8

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
!9

3. Which of the following groups is not
known to contain photoautotrophic
taxa
a. Cyanobacteria
b. Diatoms
c. Euglenids
d. Chlaymdias
e. Stramenopiles
!10

3. Which of the following groups is not
known to contain photoautotrophic
taxa
a. Cyanobacteria
b. Diatoms
c. Euglenids
d. Chlaymdias
e. Stramenopiles
!11

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
!12

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
!13

Lecture 22 Outline
• What are Fungi?
• Diversity of form
• Phylogenetic diversity
• Symbioses
!14

Lecture 22 Outline
• What are Fungi?
• Diversity of form
• Phylogenetic diversity
• Symbioses
!15

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

Figure 30.1 Fungi in Evolutionary Context
19

Predatory Fungi
21

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.
22

Fungal Decomposition

Diversity of Form
24

Figure 30.2 Yeasts
25

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.
26

Multicellular Fungi: Hyphae Used to Create Structures
27

Multicellular Fungi: Mycelia Made Up of Hyphae
28
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
29
Fruiting
Body
Vegetative
mycelia
Hyphae are used to create
structures such as rhizoids (for
anchoring) and fungal
“bodies” (known as mycleia).

Mushroom growth
30

Fungi or Not?
31

Phytophthora
Potato Late Blight
• Non-photosynthetic.
• Are absorptive heterotrophs
32
Sudden Oak Death

Stramenopiles: Oomcyetes
Phytophthora
Potato Late Blight
• Non-photosynthetic.
• Are absorptive heterotrophs
• Once were classed as fungi, but
are unrelated.
33
Sudden Oak Death

• Form spores on stalks called
fruiting bodies.
• Found in cool, moist habitats
34

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
35

• Elaborate branching
• Some reproduce by
forming chains of
spores at tips of
filaments
• Most antibiotics are
from this group
• Causative agents of
many diseases
36

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
37

Fungal reproduction
38

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.
39

Figure 30.4 Spores Galore
40

Fungal Spores
41

Puffballs
42

• 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)
Fertilization
HAPLOID (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)

Gametes
Male (n) Female (n)
Meiosis Fertilization
HAPLOID
(n)
DIPLOID (2n)
Zygote (2n)
Mature
organism (2n)
Diplontic life cycle
Elephant (Loxodonta africana)
(diploid organism)

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
47

Phylogeny of Fungi
48

Figure 30.2 Phylogeny of the Fungi
49

50

51
Know what is in
this tree

Table 30.1 Classification of fungi
52

Table 30.1 Classification of fungi
53
Know what is in
this table

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

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