19.5 Diversity of Fungi KEY CONCEPT Fungi are saprobes (decomposers)

19.5 Diversity of Fungi

KEY CONCEPT Fungi are saprobes (decomposers)


Plants and Fungi have similar and dissimilar traits

• Plants: photosynthesis; true roots, stems, and leaves; cell walls with cellulose

• Plants and Fungi: non-moving, produce spores• Fungi: absorb food with hyphae; cell walls with chitin


• Fungi are multicellular organisms, with the exception of yeasts.

– hyphae– mycellium– fruiting body


Septate and Coenocytic hyphae


Sac Fungi (Ascomycota)

• Examples– Yeasts are single-celled.– Morels and truffles are multicellular.

• Form a reproductive sac, called an ascus.


• Bread mold Zygomycota ("Conjugation Fungi")– Molds that are often found on spoiled food including:

bread, cheese and meat.– Mycorrhizae belong to this group– Form zygospores during reproduction


• Club fungi (Basidiomycota).

– include mushrooms, puffballs, and shelf fungi –reproductive structures called basidia


Imperfect Fungi (Deuteromycota)

• Group of fungi that produces asexually but sexual form is unknown

• Examples: leaf spot fungus, Penicillium, Aspergillus


Fungi reproduce sexually and asexually.

• Most fungi reproduce both sexually and asexually. – Yeasts reproduce asexually through budding.– Yeasts form asci during sexual reproduction.


• Multicellular fungi have complex reproductive cycles.

– distinctive reproductive structures

–Basidiomycota have basidia–Zygomycota have zygospores–Ascomycota have asci


• Alternation of Generations- part of reproductive cycle is asexual, part is sexual.


• All fungi form spores and zygotes.


• Fungi have + and – hyphae instead of male and female.


KEY CONCEPT Fungi recycle nutrients in the environment.


• Fungi and bacteria are the main decomposers in any ecosystem.– decompose dead leaves, twigs, logs, and animals– return nutrients (carbon, nitrogen and minerals) to the soil – absorb food quickly and recycle nutrients quickly


Fungi as pathogens

• A few fungi always cause disease• Some are normally harmless, but can grow out of control

under right conditions

Yeast can overgrowin presence of antibiotic


Human Diseases

• Yeast infections from antibiotic use• Ringworm• Athlete’s foot


• Plant Diseases –Dutch elm disease–Peach scab–Gray mold

Elm barkbeetleGray mold

Dutch elm disease


• Mutualistic Fungi – Symbiotic relationship with another organism– Both organisms benefit


Lichens

• Fungi and algae– Fungi protect the algae– Algae performs photosynthesis


Mycorrhizae– Fungi and plant roots

- Fungi absorb nutrients and water- Plant provides glucose from photosynthesis

CrossSectionof root

→


• Fungi and some insects form symbiotic relationships

Leaf cutter ants build piles of leaves and add fungus.

Fungus breaks down leaves and ants eat the mycelium!


Fungi are studied for many purposes.

• Fungi are useful in several ways.– as food – as antibiotics– as model systems for molecular biology (eukaryote cells)

Penicillum

19.5 Diversity of Fungi 19.5 Diversity of Fungi

Characteristics of Fungi Characteristics of Protists

EukaryoticMost multicellularReproduce by spores

More like zygotic L.C.Most nonmotile(nonmobile)

Except chytrids (flagellated)No Chlorophyll

not photosyntheticHeterotrophs

Absorptive filaments -- hyphae (pl)Stores glycogen

Similar to animalsCell wall chitin (polysacchride)

EukaryoticUnicellular, colonial , multicellular Reproduce by :(Gametic & alternation of generation) Some are Motile & some are NonmotileNo Chlorophyll

( Except in some greenalgae….use pigments)

Storage:Diatoms ---Store lipidsBrown Algae ---- StarchRed Algae---Storage is starch

Cell wall : Diatoms--- silicaBrown algae—alginRed algae-- Cellulose

Documents

19.5 Diversity of Fungi KEY CONCEPT Fungi are saprobes (decomposers)