Introduction to Kingdom Fungi

What is a fungus?

A eukaryotic, heterotrophic organism devoid of chlorophyll that obtains its nutrients by absorption, and reproduces by spores.

Can be multicellular or unicellular

Examples of Fungi

Mushrooms and toadstools

Moulds & mildews

Yeasts (unicellular)

Mode of nutrition

Fungi=absorptive heterotrophs release digestive enzymes into surroundings Absorb digested nutrients into cells.

Hyphae (singular, hypha)

Bodies made up of hyphae Tight mass difficult to see as separate

structures. (like the ‘mushroom’ part)

Cylindrical, branching filaments composed of a tubular cell wall filled with cytoplasm and organelles

Most fungal hyphae are 2-10 m diameter

Mycelium

Loose, branching network of hyphae under the ground.

http://www.uoguelph.ca/~gbarron/MISCELLANEOUS/hairpen.htm

How Fungi Feed

Most are saprophytes: break down dead matter Play a vital role in the recycling of nutrients.

As grown along dead matter (log), break substrate down into smaller molecules. (enzymes) Extracellular digestion.

The mycelium is the part of the fungus that is digesting material. Can be deep within a decomposing tree

branch.

Parasitic Fungi

Produce hyphae called haustoria. Can penetrate host cells without killing them. Athlete’s foot, ringworm, dandruff.

C. Myrmecophila parasitizes animals.When spore lands on ant, grows in ant’s body hyphae spread through ant’s body, digesting tissues (digesting) eventually forms the ‘sex organ’ of the fungus by growing out of ant’s body.

Symbiotic Fungi

Symbiotic fungi (mutual benefit) most trees have fungi living in close contact with roots (mycorrhiza) Fungi absorbs nutrients from soil and transfers to roots Fungi benefits by absorbing nutrients from plants

some live with algae/cyanobacteria(lichens –often seen on tree trunks)

Fungi provide algae/photosynthetic bacteria with H2O and CO2 Algae/cyanobacteriaprovides nutrients for fungi

Reproduction

Can reproduce asexually and sexually

Fragmentation

Asexual

pieces of hyphaebreak off and grow into new mycelia Spore Formation

Asexual

produced by mitosis OR

Sexual

produced by meiosis

Spores:windblown reproductive cells for dispersal to new locations produced in large numbers

Note: sexual reproduction used during unfavorable conditions

Classification

4 subgroupsZygosporefungi –eg. bread mouldsClubfungi –eg. puffballs, mushroomsImperfectfungi –eg. Penicillium, Blue cheese Sacfungi –eg. truffles, yeast

Independent Reading

Read the sections on zygospores, club fungi, sac fungi, and imperfect fungi.

Make brief notes on these groups, and in your notes make sure to: Give an example of this type of fungi BRIEFLY describe how they reproduce.

Seatwork/Homework

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