Ch. 21 Fungi

What did Mr. Fungus say to Ms. Algae, when he proposed?

I lichen you!

Ch. 21 Outline

• 21-1: The Kingdom Fungi– What are Fungi?– Structure and Function of Fungi– Reproduction in Fungi– How Fungi Spread

• 21-2: Classification of Fungi– The Common Mold– The Sac fungi– The Club Fungi– The Imperfect Fungi

Ch. 21 Outline

• 21-3: Ecology of Fungi– All Fungi are Heterotrophs– Fungi as Decomposers– Fungi as Parasites– Symbiotic Relationships

What are Fungi

• Fungi used to be classified with plants, but they are actually very different than plants

• Fungi are eukaryotic heterotrophs that have cell walls– Cell walls made up of chitin (Complex carbohydrate

found in the exoskeleton of insects)

• Fungi do not ingest their food, they break it down outside their bodies by secreting enzymes. Then, they absorb it.

Structure and Function of Fungi

• All fungi are multicellular except for yeasts

• Hyphae: thin filaments that make up fungi.– Some hyphae have cross walls in them (cell

walls with openings in them)– Hyphae have many nuclei in them

Hyphae

Hyphae Without Cross Walls

Nuclei

Cell wall

Nuclei

Cytoplasm

Cross wall

Cell wall

Cytoplasm

Hyphae With Cross Walls

Structure and Function of Fungi

• The bodies of multicellular fungi are composed of many hyphae tangles together into a thick mass called a mycelium.– This gives fungi a very large surface area to absorb

nutrients.

• Fruiting body: reproductive structure growing from the mycelium– Ex. The Part of the mushroom you see!

Fruiting Body and Mycelium

Mycelium

Fruiting body

Hyphae

Reproduction in Fungi

• Most fungi reproduce both asexually and sexually

• Asexual happens when a hypha breaks off and grows on its own or by the production of spores– Spores: reproductive cell that is capable of growing

into new organisms by mitosis alone

– Sprorangia: the structure that produce spores

• Sexual two different fungi mate

How Fungi Spread

• Fungal spores are found in almost every environment.– Ex. Mold grows everywhere it seems!

• Many spores are light and dry easily scattered by wind.

• Others are dispersed by animals.

Classification of Fungi

• There are over 100,000 species of fungi. They are classified based on their structure and method of reproduction.

• Four main groups:– Zygomycota (common molds)– Ascomycota (sac fungi)– Basidiomycota (club fungi)– Deuteromycota (Imperfect fungi)

Concept Map

are divided into the phyla

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Section 21-2

Fungi

Common molds

Imperfect fungi

Sac fungiClub fungi

AscomycotaZygomycota Basidiomycota Deuteromycota

The Common Molds

• Zygomycetes are the molds you see on cheese, breads, and meat. They are characterized by the zygospore in their life cycle.

• Zygospore: resting spore that contains zygotes formed during the sexual phase of the life cycle.

• Rhizoid: root-like structure that anchors the fungi

Black Bread Mold

FERTILIZATION

Diploid

Haploid

MEIOSIS

Sexual ReproductionAsexual

Reproduction

Zygospore (2N)

Spores (N)

Sporangium

Zygospore (2N)

+ Mating type (N)Stolons

Rhizoids

- Mating type (N)Spores (N)

Sporangiophore

Sporangium

Gametangia

The Sac Fungi

• The phylum Ascomycota is named for the ascus, a reproductive structure that contains spores.

• Ascospores: the spores produced in an ascus.

• Yeasts are an example of Sac Fungi.– Uses of yeast: baking breads and brewing

alcohol

Ascomycota

FERTILIZATION

MEIOSIS

HYPHAE FUSE

Diploid

Haploid

Sexual Reproduction

Asexual Reproduction

Hypha (N)

Hypha (N)

Conidiophore

Conidia (N)

+ Mating type (N)

- Mating type (N)

8 Ascospores (N)

Ascus

Zygote (2N)

Ascus (N + N)

Fruiting body (N + N)Hyphae (N + N)

GametangiaAsci

Hyphae (N)

Ascomycota

The Club Fungi

• The Phylum Basidiomycota gets its name from a specialized reproductive structure that resembles a club.– Basidium: the spore-bearing structure in

Basidiomycota

• Example of club fungi: Mushrooms

Basidiomycota

FERTILIZATION

MEIOSIS

HYPHAE FUSE

Fruiting body (N + N)

Button

Secondary mycelium (N + N)

Primary mycelium (N)

+ Mating type (N)

- Mating type (N)

Basidiospores (N)

Zygote (2N)

Basidia (N + N)

Gills lined with basidia

Gills

Stalk

Base

Cap

Haploid

Diploid

The Imperfect Fungi

• Deuteromycota is an extremely varied phylum. It is composed of those fungi that are not placed in the other phyla because researches have never been able to observe a sexual phase in their life cycle.

• Example: Penicillin notatum– (The Source of Penicillin)

All Fungi are Heterotrophs

• Many Fungi are saprobes: obtain their food from decaying organic matter.

• Others are parasites or symbiotes (live in beneficial relationships with another organism).

Fungi as Decomposer

• Fungi play an important role in ecosystems because they break down and recycle nutrients.

• They secrete enzymes outside of their hyphae and then absorb nutrients.

Fungi as parasites

• Parasitic fungi cause serious plant and animal diseases

• Ex. Athlete’s Foot

Symbiotic Relationships

• Some fungi form symbiotic relationships in which both partners benefit. These are often essential to the ecosystem.

• Lichens: association between a fungi and green algae or cyanobacteria.– The algae/cyanobacteria provide the fungus with food (since

they are photosynthetic)– The fungus provides a large surface area to collect water and

minerals– Lichens can exist in extreme environments (drought, cold) and

are many times the first to inhabit in an area.

Lichens

Symbiotic Relationships

• Mycorrhizae: The association of plant roots and fungi– Plants provide the food (photosynthesis)– Fungi increases the surface area for

absorption– About 80% of plants are in this type of

relationship– This association is essential for many plants

to survive and reproduce

Mycorrhizae