1. Kingdom Fungi The characteristics of fungi The evolution of the fungi
Fungal classification
Fungal life styles

2. Choanoflagellates
Red algae
Green algae
Land plants
Myxozoa
Fungi
Animals
Figure: 29.2
Caption:
This phylogeny shows the evolutionary relationships among the green plants, animals, fungi, and various groups of protists. Choanoflagellates are solitary or colonial protists found in fresh water and are introduced in Chapter 30.
The ancestor of fungi is thought to have been a protist similar to the ancestor of animals

3. The Characteristics of Fungi
Fungi are NOT plants
Hyphae = tubular units of construction
Mycelium = extensive, feeding web of hyphae
Heterotrophic by absorption
Reproduce by spores
Ecologically pivotal roles

4. Hyphae Tubular Hard wall of chitin
Crosswalls may form compartments (± cells)
More than one nucleus
Grow at tips
Chitin is the same material used by Arthropods (Insects, crabs, etc.) in their exoskeletonsa
Nuclei of fungi are hard to see without stains

5. Hyphae grow from their tips
Hyphal growth
Hyphae grow from their tips
This wall is rigid
Only the tip wall is plastic and stretches

6. Mycelium = extensive, feeding web of hyphae
Fungal mycelia can be huge, but they usually escape notice because they are subterranean.
One giant individual of Armillaria ostoyae in Oregon is 3.4 miles in diameter and covers 2,200 acres of forest,
It is at least 2,400 years old, and weighs hundreds of tons.
(Actually no one has seen one this of this extent – but cultures have been taken from soil over that area and all isolates have been found to be the same individual)
Ten cubic centimeters of rich organic soil may have fungal hyphae with a surface area of over 300 cm2
mycelium
Mycelia
have a huge surface area
are the ecologically active bodies of fungi

7. Heterotrophic by Absorption
Fungi get carbon from organic sources
Hyphal tips release enzymes
Enzymatic breakdown of substrate
Products diffuse back into hyphae
Enzymatic breakdown
Nucleus hangs back
and “directs”
Products
Enzymes
Product diffuses back
into hypha and is used

8. Reproduce by spores Spores are reproductive cells Formed: Sexual
Asexual
Formed:
Directly on hyphae
Inside sporangia
Fruiting bodies
Fungi reproduce by releasing spores that are produced either sexually or asexually.
The output of spores from one reproductive structure is enormous, with the number reaching into the trillions.
Dispersed widely by wind or water, spores germinate to produce mycelia if they land in a moist place where there is food.
Penicillium hyphae
Pilobolus sporangia
Amanita fruiting body

9. fruiting bodies
both consist
of hyphae
mycelium

10. Multicellular and Unicellular fungi
Figure 29.3
138 µm
3.73 µm

11. Simple Fungi Fig 31.5 Chytridium growing on spores
A mold is a rapidly growing, asexually reproducing fungus.
The mycelia of these fungi grow as saprobes or parasites on a variety of substrates.
Also used in foods (Blue cheese, Tempeh) and in industrial production of drugs
Early in life, a mold, a term that applies properly only to the asexual stage, produces asexual spores.
Later, the same fungus may reproduce sexually, producing zygosporangia, ascocarps, or basidiocarps
Some molds go through a “fake sex” process
Fig 31.5 Chytridium growing on spores

12. Molds Fig 31.6 Rhizopus on strawberries
Most of the 600 zygomycote, or zygote fungi, are terrestrial, living in soil or on decaying plant and animal material.
Asexual reproduction in sporangia
One zygomycote group form mycorrhizas, mutualistic associations with the roots of plants.
Fig 31.6 Rhizopus on strawberries

13. Molds Many human importances Food spoilage Food products
Antibiotics, etc.
A mold is a rapidly growing, asexually reproducing fungus.
The mycelia of these fungi grow as saprobes or parasites on a variety of substrates.
Also used in foods (Blue cheese, Tempeh) and in industrial production of drugs
Early in life, a mold, a term that applies properly only to the asexual stage, produces asexual spores.
Later, the same fungus may reproduce sexually, producing zygosporangia, ascocarps, or basidiocarps
Some molds go through a “fake sex” process
Noble Rot - Botrytis
Fig Antibiotic activity

14. Club Fungi A mold is a rapidly growing, asexually reproducing fungus.
The mycelia of these fungi grow as saprobes or parasites on a variety of substrates.
Also used in foods (Blue cheese, Tempeh) and in industrial production of drugs
Early in life, a mold, a term that applies properly only to the asexual stage, produces asexual spores.
Later, the same fungus may reproduce sexually, producing zygosporangia, ascocarps, or basidiocarps
Some molds go through a “fake sex” process

15. Yeasts Single celled fungi Adapted to liquids Plant saps Water films
Moist animal tissues
Bread and wine yeast, the budding yeast, Saccharomyces
Easily cultured. For a time, this was the most important organism for studying the molecular genetics of eukaryotes
Thus, Saccharomyces is arguably the most important organism known to humans
Candida causes diseases of humans, usually experiencing chemical imbalance or immune problems
Candida
Saccharomyces

16. Schizosaccharomyces octospora – fermenter of Palm Wine
This yeast is isolated from palm wine (fermented sap of the oil palm in West Africa)
Note that it is forming 8-spored asci (“octospora”) – an indication that it is an Ascomycote
10 μm

17. Fungal Ecology ECOLOGICAL ROLES: Saprobes Parasites Mutualists
Saprobic fungi absorb nutrients from nonliving organisms.
Parasitic fungi absorb nutrients from the cells of living hosts.
Some parasitic fungi, including some that infect humans and plants, are pathogenic.
Mutualistic fungi also absorb nutrients from a host organism, but they reciprocate with functions that benefit their partner in some way

18. Fungal Ecology Saprobes Decomposers Mostly of plants, some animals
Saprobic fungi absorb nutrients from nonliving organisms.
Parasitic fungi absorb nutrients from the cells of living hosts.
Some parasitic fungi, including some that infect humans and plants, are pathogenic.
Mutualistic fungi also absorb nutrients from a host organism, but they reciprocate with functions that benefit their partner in some way

19. Fig 31.6 Rhizopus on strawberries
Most of the 600 zygomycote, or zygote fungi, are terrestrial, living in soil or on decaying plant and animal material.
Asexual reproduction in sporangia
One zygomycote group form mycorrhizas, mutualistic associations with the roots of plants.
Fig 31.6 Rhizopus on strawberries

20. Fungi are absorptive heterotrophs that secrete digestive enzymes and are major decomposers of dead organic material.

21. Fungal Ecology Parasites Harm host Mostly on plants, some animals
Saprobic fungi absorb nutrients from nonliving organisms.
Parasitic fungi absorb nutrients from the cells of living hosts.
Some parasitic fungi, including some that infect humans and plants, are pathogenic.
Mutualistic fungi also absorb nutrients from a host organism, but they reciprocate with functions that benefit their partner in some way

22. Rusts & Smuts A rust growing on a currant leaf 0.5 cm
Rusts are Basidiomycote plant parasites with, often, very complex life cycles that alternate between two different plant hosts. They can produce up to 5 different types of spores and cause considerable damage, particularly to economically important plant hosts that are non-natives.

23. Parasitic fungi cause major damage to crops such as wheat, corn, and barley.
Many have evolved resistance to fungicides.

24. Fungal Ecology Mutualists Mycorrhizas Lichens Others
Saprobic fungi absorb nutrients from nonliving organisms.
Parasitic fungi absorb nutrients from the cells of living hosts.
Some parasitic fungi, including some that infect humans and plants, are pathogenic.
Mutualistic fungi also absorb nutrients from a host organism, but they reciprocate with functions that benefit their partner in some way

25. Mycorrhizas “Fungus roots” Mutualism between: Several kinds
Fungus (nutrient & water uptake for plant)
Plant (carbohydrate for fungus)
Several kinds
Extremely important ecological role of fungi!
Half of the mushroom-forming fungi (basidiomycota) form mycorrhizas with trees
Some people think that the spongy tissue in roots evolved as a place where fungi could invade to form early links with plants that helped them survive the harsh life on early earth

26. Figure 29.9a Ectomycorrhizal fungi (EMF) Root cells EMF Figure: 29.9a
Caption:
(a) Ectomycorrhizal fungi (EMF) form a dense network around the roots of plants. The combination of root and fungus is called a mycorrhiza. The drawing shows how the interaction works in EMF. Note that their hyphae penetrate the intercellular spaces of the root, but do not enter the cells themselves. 
EMF

27. Mutualism: Relationships between fungi and hosts that are mutually beneficial
Increasing the diversity of mycorrhizae in a given habitat increases plant species richness and productivity

28. Lichens “Mutualism” between Form a thallus
Fungus – protection against drying
Alga or cyanobacterium – provides food
Form a thallus
Foliose
Fruticose
Crustose
Thallus is a plant-like body that doesn’t have roots, stems or leaves
Thallus doesn’t look like either partner
Dual nature of thalli was not fully understood until early 1900’s
Fungus gives the name to the lichen (by agreement)
Fungus usually, but not always, an Ascomycote (in 8+ independent orders)
Algae green. If bluegreen bacteria present, lichens fix nitrogen (turn atmospheric nitrogen into amino acid nitrogen in proteins)
Fig 31.16

30. Lichen internal structure
Asci
produced by
fungus
Asexual reproduction
occurs when “mini-lichens”
are produced.
Fungal layer
Algal layer
Figure: 29.11a
Caption:
(a) In a lichen, green algae or cyanobacteria are enmeshed in a dense network of fungal hyphae. In this example, the fungal participant is an ascomycete.
Fungal layer
Substrate

31. Lichen internal structure
The nature of lichen symbiosis is may also be described as mutual exploitation instead of mutual benefit.
Lichens live in environments where neither fungi nor algae could live alone.
While the fungi do not not grow alone in the wild, some (but not all) lichen algae occur as free-living organisms.
If cultured separately, the fungi do not produce lichen compounds and the algae do not “leak” carbohydrate from their cells.
In some lichens, the fungus invades algal cells with haustoria and kills some of them, but not as fast as the algae replenish its numbers by reproduction.
Lobaria oregana prefers old-growth conifer canopies in forests with clean air.

32. Lichens as biomonitors
Some species more sensitive
Which species are present can indicate air quality
Analysis for sulfur and heavy metals in resistant species shows levels relative to levels in the environment