Fungi - University of Texas at Austinweb.biosci.utexas.edu/zhao/bio301L/PDF-Documents/Lecture5.pdfFungi The multicellular eukaryotic organisms that feed on dead or decaying organic

FungiFungi

The multicellular eukaryotic organisms that feed on dead or decaying organic material

Outline of TodayOutline of Today’’s lectures lecture

� I. Fungi• Key concepts• Representatives• Characteristics• Classification• Roles of fungi

� II. Mitosis & Meiosis

� III. Life cycle : 1. Animal 2. Human 3. Fungi

Key Concepts:Key Concepts:

� Fungi are heterotrophs

� Fungi secrete enzymes that digest food outside

their body, then fungal cells absorb breakdown

products (extra-cellular digestion)

� Fungi do not ingest food and Fungi cannot move

� Most fungi are multicelled

� A portion of the fungal hyphae becomes

modified and forms a reproductive structure

� Many fungi are symbiotic with other organisms

Fungal Species from Fungal Species from Southeastern VirginiaSoutheastern Virginia

Purple Coral

Fungus ClavariaRubber Cup

Fungus Sarcosoma

Fungal Species from Fungal Species from Southeastern VirginiaSoutheastern Virginia

Big Laughing

Mushroom Gymnophilus

Trumpet Chanterelle

Craterellus

Fungal Species from Fungal Species from Southeastern VirginiaSoutheastern Virginia

Scarlet Hood

Hygrophorus

Characteristics & ClassificationCharacteristics & Classification� Mode of Nutrition

� Heterotrophs

� Saprobes

� Parasites

� Major Groups (100,000

species)

Chytrids

Glomeromycetes

� Zygomycetes (Zygomycota)

� Sac fungi (Ascomycota)

� Club fungi (Basidiomycota)

� Life Cycles

� Spores

(reproductive

cells)

� Mycelium (mesh

of branched

filament)

� Hypha (filament)

hyphae (plural)

Chytrids (1,000 species)

25 μμμμm

25 μμμμm

Zygomycetes (1,000 species)

Glomeromycetes (160 species)

Ascomycetes (65,000 species)

Basidiomycetes (30,000 species)

Hyphae

Fungal

hypha

Asexual Reproduction inAsexual Reproduction inRhizopus stoloniferRhizopus stolonifer

Sexual Reproduction of Fungi Sexual Reproduction of Fungi

Club fungi

Sexual Reproduction of Fungi Sexual Reproduction of Fungi

Slide 4

Fig. 24.4, p. 395

nuclear fusion

After nuclear fusion, the club-

shaped structure (now 2n) will

produce and bear haploid spores

at the four tips of the cell.

meiosis

cytoplasmic

fusion

Diploid Stage

Haploid Stage

Club-shaped

structures

having two

nuclei (n + n)

form at the

margin of each

gill.gills

After cytoplasmic fusion, a

“dikaryotic” (n + n) mycelium

gives rise to spore-bearing

bodies (e.g., mushrooms).

cap

stalk

spore (n)

Spores are released.

Each germinating spore

gives rise to a hypha

that grows and becomes

a branching mycelium.

hypha

hypha in

mycelium

Roles of Fungi

�Decomposers &

recyclers of nutrients

�Food

�Medicine

The antibiotic

penicillin was

first isolated from

the fungus

Penicillium

�DiseasesCrops, fruits, food

Club FungiClub Fungi

Light-red

coral fungus

Ramaria

Shelf fungus

Polyporus

Club Fungi MushroomsClub Fungi Mushrooms

Amanita muscaria

- hallucinogenic

Amanita ocreata

- fatal

LichenLichen

� Symbiosis

�Lichen

Lobaria oregana

II.II. Mitosis & MeiosisMitosis & Meiosis�Mitosis – A type of eukaryotic cell division, which results two daughter cells that are genetically identical to the parental cell.

�Meiosis - A type of eukaryotic cell division,

which results four daughter cells that have

only a half number of the parental cell’s

chromosomes.

Mitosis

Meiosis

III.III. Life CycleLife Cycle

�Life cycle – the events in the life of an organism from one generation to the next.

�Life cycle: 1. Animal 2. Human 3. Fungi

Animal Life Cycle

Human Life Cycle

Fungus Life Cycle