contractile vacuole action

• Contractile vacuole action

• Amoeboid movement

• See it!

• Chapter 31 ~ Fungi

It is as large as 1,665 football fields combined. It is 3.4 square miles in size and covers 2,200 acres of land in the Blue Mountains of eastern Oregon.

Humongous Fungus Honey Mushroom Blankets Forest, Kills Trees

FungiFungi

• Heterotrophic by absorption (exoenzymes)

• Decomposers (saprobes), parasites, mutualistic symbionts (lichens)

• Hyphae: body filaments •septate (cross walls) •coenocytic (no cross walls)

• Mycelium: network of hyphae• Chitin cell walls (polysaccharide)

Nuclei

Septate hypha

Septum

Pore

Cell wallCell wall

Nuclei

Coenocytic hypha

LE 31-2LE 31-2

Reproductive structure

Hyphae

Spore-producingstructures

Mycelium

20 µm

Fungus Life CycleFungus Life Cycle

Bread Mold Life cycle

Most have 3 distinct phases:

1. Haploid (n)

2. Heterokaryotic (n + n) (think of Sordaria)

3. Diploid (2n)

Asexual phases: (n spores, n clones)

Sexual Phases: (n spores, w/ genetic variety)

Plasmogamy (cytoplamic fusion)Dikaryotic (n + n)Karyogamy (nuclei fusion)Diploid (2n)Meiosis (spores n)

Haploid (n)

Key

Heterokaryotic(n + n))

Diploid (2n)

PLASMOGAMY(fusion of cytoplasm)

Heterokaryoticstage

KARYOGAMY(fusion of nuclei)

Mycelium

SEXUALREPRODUCTION

Zygote

Spores

GERMINATIONMEIOSIS

Spore-producingstructures

ASEXUALREPRODUCTION

Spores

GERMINATION

Spore-producingstructures

Fungi Diversity, IFungi Diversity, I

• Phy: Chytridiomycota •aquatic fungi; chytrids •lineage closest to protists (flagella)

• Phy: Zygomycota •Rhizopus (food mold) •mycorrhizae: mutualistic with plant roots •zygosporangia: resistant structure (freezing and drying)

Fungi Diversity, IIFungi Diversity, II

• Phy.: Ascomycota •sac fungi • yeasts, truffles, morels,

Sordaria •asci: sexual spores •conidia: asexual spores

• Phy.: Basidiomycota • club fungus •mushrooms, puffballs, shelf fungus, rusts •basidiocarps: produce sexual spores

Specialized Lifestyles, ISpecialized Lifestyles, I

• Molds •only the asexual stage

(asexual spores) •Penicillium (antibiotic,

cheese)

• Yeasts •unicellular, asexual budding •Saccharomyces (bread,

alcohol)

Specialized Lifestyles, IISpecialized Lifestyles, II

• Lichens • symbiotic association held in a hyphae mesh •alga provides food, fungus provides physical environment •pioneer organisms •air pollution detection

• Mycorrhizae •root and fungi mutualism •found in 95% of vascular plants •exchange of organic minerals •increases absorptive surface of roots