Chapter 31 Why did the mushroom go to the party??? Because he’s a fun-gi!

Chapter 31Chapter 31

Why did the mushroom go to the Why did the mushroom go to the party??? Because he’s a fun-gi!party??? Because he’s a fun-gi!

Characteristics of FungiCharacteristics of Fungi

1.) All are eukaryotic heterotrophs.1.) All are eukaryotic heterotrophs.

2.) Feed by absorption.2.) Feed by absorption.

a.) Excrete exoenzymes into their environment a.) Excrete exoenzymes into their environment which break down organic matter into smaller which break down organic matter into smaller compounds.compounds.

b.) Fungi then absorb the smaller molecules.b.) Fungi then absorb the smaller molecules.

Characteristics of FungiCharacteristics of Fungi3.) Most are multicellular.3.) Most are multicellular.

a.) Exception: single-celled yeastsa.) Exception: single-celled yeasts

4.) Structure of multicellular fungi:4.) Structure of multicellular fungi:a.) Bodies form a network of tiny filaments called a.) Bodies form a network of tiny filaments called hyphae.hyphae.

b.) Hyphae: composed of tubular cell walls b.) Hyphae: composed of tubular cell walls surround the plasma membrane & cytoplasm of surround the plasma membrane & cytoplasm of the cells.the cells.

i.) Cell walls contain chitin (also found in i.) Cell walls contain chitin (also found in exoskeletons of insects).exoskeletons of insects).


c.) Hyphae form an interwoven mass c.) Hyphae form an interwoven mass called a mycelium which surrounds & called a mycelium which surrounds & infiltrates the organic matter on which the infiltrates the organic matter on which the fungus feeds. fungus feeds.

d.) Mycelia maximize the surface area of d.) Mycelia maximize the surface area of the fungus to make feeding more efficient the fungus to make feeding more efficient structure/function structure/function


e.) Hyphae are typically divided into e.) Hyphae are typically divided into individual cells by cross walls called septa.individual cells by cross walls called septa.

i.) Septa have pores to allow i.) Septa have pores to allow organelles to flow from cell to cell.organelles to flow from cell to cell.

ii.) Fungi without septa are called ii.) Fungi without septa are called coenocytic. Consist of cytoplasmic coenocytic. Consist of cytoplasmic mass mass with numerous nuclei.with numerous nuclei.

Characteristics of FungiCharacteristics of Fungi5.) Hyphae can be specialized for various 5.) Hyphae can be specialized for various

functions:functions:

a.) Some can penetrate & feed on living tissues a.) Some can penetrate & feed on living tissues – these hyphae are called haustoria.– these hyphae are called haustoria.

b.) Mycorrhizal fungi form mutualistic b.) Mycorrhizal fungi form mutualistic relationships with plants. They deliver ions that relationships with plants. They deliver ions that plants cannot take up & receive nutrients in plants cannot take up & receive nutrients in return. Most plants have these & do not grow return. Most plants have these & do not grow well without them!well without them!

Reproduction in FungiReproduction in Fungi1.) Most can reproduce either sexually or asexually by 1.) Most can reproduce either sexually or asexually by

producing (usually) A LOT of spores. producing (usually) A LOT of spores.

a.) Nuclei of hyphae & spores are typically haploid.a.) Nuclei of hyphae & spores are typically haploid.

2.) Sexual reproduction:2.) Sexual reproduction:

a.) Hyphae from different mycelia release pheromones & a.) Hyphae from different mycelia release pheromones & grow toward one another.grow toward one another.

b.) Hyphae then fuse together – called plasmogamy.b.) Hyphae then fuse together – called plasmogamy.

Reproduction in FungiReproduction in Fungic.) Haploid nuclei from each “parent” mycelium c.) Haploid nuclei from each “parent” mycelium do not fuse right away. These nuclei coexist & do not fuse right away. These nuclei coexist & we call the mycelium a heterokaryon (“different we call the mycelium a heterokaryon (“different nuclei”).nuclei”).

d.) Haploid nuclei finally fuse in a process called d.) Haploid nuclei finally fuse in a process called karyogamy.karyogamy.

e.) The “zygote” that is formed usually e.) The “zygote” that is formed usually undergoes meiosis & the mycelium then undergoes meiosis & the mycelium then produces structures that produce & disperse produces structures that produce & disperse spores (with new combination of genes).spores (with new combination of genes).

Reproduction in FungiReproduction in Fungi3.) Asexual reproduction:3.) Asexual reproduction:

a.) Most fungi can do this a.) Most fungi can do this as well as sexually as well as sexually reproduce.reproduce.

b.) Molds reproduce b.) Molds reproduce asexually much of the time.asexually much of the time.

c.) Yeast reproduce c.) Yeast reproduce asexually by simple cell asexually by simple cell division or “budding.”division or “budding.”

Fungal EvolutionFungal Evolution

1.) Fungal ancestor was most likely a 1.) Fungal ancestor was most likely a single-celled, flagellated protist.single-celled, flagellated protist.

2.) Fungi & animals are more closely 2.) Fungi & animals are more closely related to each other than to other related to each other than to other eukaryotes. Share a common ancestor & eukaryotes. Share a common ancestor & diverged about 1.5 bya.diverged about 1.5 bya.

Fungi PhylogenyFungi Phylogeny

Types of FungiTypes of Fungi

1.) Chytrids – mostly 1.) Chytrids – mostly aquatic. Can be aquatic. Can be saprobes or saprobes or parasites.parasites.

a.) Unique for a.) Unique for producing flagellated producing flagellated spores called spores called zoospores.zoospores.


2.) Zygomycetes – 2.) Zygomycetes – includes molds includes molds common on fruits or common on fruits or bread.bread.

a.) Produce spores a.) Produce spores called zygosporangia called zygosporangia – resistant to harsh – resistant to harsh environments.environments.


3.) Glomeromycetes: all form a type of 3.) Glomeromycetes: all form a type of mycorrhizae present in about 90% of mycorrhizae present in about 90% of plants.plants.

a.) Actually penetrate cell walls of plant a.) Actually penetrate cell walls of plant root cells.root cells.

Types of FungiTypes of Fungi4.) Ascomycetes: commonly 4.) Ascomycetes: commonly

called sac fungi. Morels, called sac fungi. Morels, yeasts, trufflesyeasts, truffles

a.) Produce spores in a.) Produce spores in “sacs” called asci.“sacs” called asci.

b.) Some are plant b.) Some are plant parasites, some important parasites, some important saprobes, many live saprobes, many live symbiotically in algae in symbiotically in algae in what is commonly called a what is commonly called a lichen.lichen.

Types of FungiTypes of Fungi5.) Basidiomycetes: 5.) Basidiomycetes:

mushrooms & shelf fungi, mushrooms & shelf fungi, molds, plant parasites molds, plant parasites called smuts.called smuts.

a.) Mushroom is actually a.) Mushroom is actually a reproductive body a reproductive body sprouted by mycelium. sprouted by mycelium. Can grow quickly – Can grow quickly – overnight. overnight.

Fungal Impacts on Fungal Impacts on Ecosystems & HumansEcosystems & Humans

1.) Decomposers1.) Decomposers

2.) Symbiotic Relationships2.) Symbiotic Relationships

a.) Mycorrhizae – almost all vascular plants have a.) Mycorrhizae – almost all vascular plants have them & depend on them to increase absorption of them & depend on them to increase absorption of water, minerals.water, minerals.

b.) With ants & termites: “farm” fungus by feeding it b.) With ants & termites: “farm” fungus by feeding it pieces of leaves. Fungi break down leaves into pieces of leaves. Fungi break down leaves into substance digested by insects. substance digested by insects.


c.) Lichens: algae (or cyanobacteria) & fungus c.) Lichens: algae (or cyanobacteria) & fungus found growing on rocks, logs, etc in close association found growing on rocks, logs, etc in close association with one another. Some of 1with one another. Some of 1stst organisms to colonize organisms to colonize new environments & form soil.new environments & form soil.

3.) Pathogens3.) Pathogens

a.) Most fungi pathogens are plant parasites.a.) Most fungi pathogens are plant parasites.

b.) 2 types of ascomycetes are responsible for killing b.) 2 types of ascomycetes are responsible for killing millions of elms and chestnuts.millions of elms and chestnuts.


c.) Many parasitize crops – some c.) Many parasitize crops – some producing chemicals that are toxic to producing chemicals that are toxic to humans.humans.

i.) Parasite of rye can cause i.) Parasite of rye can cause ergotism: ergotism: gangrene, spasms, burning gangrene, spasms, burning sensations, sensations, hallucinations & temporary hallucinations & temporary

insanity…one insanity…one compound from this compound from this fungus is a raw material fungus is a raw material used to used to

make make LSD.LSD.


d.) Few species parasitize humans -d.) Few species parasitize humans -called mycosis (fungal infection)…called mycosis (fungal infection)…

i.) Skin mycoses: Ringworm, i.) Skin mycoses: Ringworm, athlete’s athlete’s footfoot

ii.) Systemic mycoses: spread ii.) Systemic mycoses: spread through body causing serious illness. through body causing serious illness.


5.) Practical Uses of Fungi:5.) Practical Uses of Fungi:

a.) Food – mushrooms, used to ripen chesses, a.) Food – mushrooms, used to ripen chesses, used to produce citric acid for soda. Yeast is used to produce citric acid for soda. Yeast is used to produce alcohol & raise breadused to produce alcohol & raise bread

b.) Extracts are used as medicines (penicillin b.) Extracts are used as medicines (penicillin is from a mold)is from a mold)

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Chapter 31 Why did the mushroom go to the party??? Because he’s a fun-gi!