Fungi

A spore stalk from a fungus that killed a carpenter ant

grew upward from the ant’s head.

All Fungi are….

• eukaryotic heterotrophs

• What does eukaryotic mean?

• What is a heterotroph?

Categories of Fungi

1. Multicellular– Most fungi– Do not contain chloroplasts– Honey mushroom

2. Unicellular– Yeasts

Cell Walls

• Plants - made of cellulose

• Fungi - made of chitin

–Chitin is strong and flexible

Fungi Parts

Fungi Parts - Hyphae

• Threadlike filaments that make up the basic structure of the fungi’s body (all parts)

• Provide support• Provide a large surface area for

nutrient absorption

Fungi Parts - Mycelium

• A netlike mass made up many hyphae

• Formed below ground

• Absorb nutrients

Fungi Parts - Fruiting Body

• Reproductive structure

• Above ground portion

Obtaining Nutrients & Energy

1. Through Decomposition• Saprophytic fungi - feeds

on dead organisms or organic wastes

• Recycle nutrients

Obtaining Nutrients & Energy

2. Through Parasitism

–Absorb nutrients from living cells of another organisms (a host)

These parasitic fungi grow thread-like mycelium throughout the tree on which they grow. The mycelium steal nutrients from the tree, and cause damage to the

structure of the tree.

Obtaining Nutrients & Energy

3. Through Mutualism–With another organism, such as a

plant or alga– Ex: mycelia on a root of a soybean plant

• Fungus receives sugar from the host plant

• Mycelia increase water uptake and mineral absorption for the host plant

Asexual Reproduction

• Budding

–New cell develops while attached to parent cell

Asexual Reproduction

• Fragmentation

–The mycelium of a fungus is broken off or “fragmented”

–Can grow into new mycelia

Reproduction

• Spore - a reproductive cell, haploid, has a hard outer coat, will develop into a new organism, produce new hyphae

–Asexual reproduction

• Sexual reproduction

–Produce spores though meiosis

Branches of Fungi

1. Chytrids• yeast

2. Common Molds• bread mold

3. Sac Fungi• morels & truffles, yeast

4. Club Fungi• Mushrooms

5. Imperfect Fungi• Penicillium

Great Barred Frog infected with the chytrid fungus

Truffle (fungus)

Bread Mold

Mushrooms

Chytrids

• DNA and protein sequences more similar to fungi than protists

• Chitin-containing cell walls

Common Molds• Stolons:

–Hyphae that spread across the surface of food

• Rhizoids: –Penetrates the food and absorbs nutrients

Sac Fungi• Conidiophores

–Spores form at the tips, so they are easily dispersed by wind, water and animals(Most spores form inside the sporangia, not at the tip)

Club Fungi

• Dikaryotic mycelia

–Each cell has two nuclei

Club Fungi• Reproduce sexually:

1. Form a basidiocarp (fruiting body)2. Hyphae (basidia) produce spores3. Two nuclei fuse to form a dipoid

nucleus4. Divides by meiosis into 4 haploid

spores5. Dispersed by wind, water, animals

Imperfect Fungi

• Very diverse group

• Lack a sexual stage of reproduction

–Called “Imperfect Fungi”–Most fungi reproduce both asexually

and sexually

Lichens

• Symbiotic relationship between a fungus and a alga–Fungus provides protection–The alga provides food (photosynthesis)

Lichens are Bioindicators

• Very sensitive to changes in environmental conditions

• By observing lichen populations and their health, we can monitor the effects of pollution in an area– More pollution Fewer lichens– Less pollution More lichens

Benefits of Fungi• Decomposers - recycle nutrients• Medical uses - penicillin (antibiotic),

reduce high blood pressure, control excessive bleeding, treat migtaine headaches, promote contractions during childbirth, prevent organ rejection in organ transplant patients

• Food - mushrooms, yeast, truffles• Bioremediation - cleaning the

environment of pollutants

Harmful Fungi• American elm trees & American chestnut

trees killed by certain fungi• Agricultural crops damaged• Can act as parasites in humans & other

organisms–Athlete’s foot, ringworm, yeast

infections

Moldy Bread

• Why should you throw away the whole loaf of bread, even if the mold only appeared on one piece?