Fungi have cell walls made of chitin, reproduce both sexually and asexually, and obtain nutrients by absorption. They consist of thread-like hyphae that grow and branch to form a mycelium. Fungi play important ecological roles as decomposers, pathogens, and mutualists with other organisms like plants and algae. They are classified into phyla based on their structures and life cycles, and include yeasts, molds, mushrooms, and others. Fungi interact with humans in many ways as food, medicine, research tools, and sometimes as pathogens.

1. Fungal Biodiversity
Pl Path 501

2. • Biological diversity
simply means the
diversity, or variety, of
plants and animals and
other living things in a
particular area or region
• Also means the number,
or abundance of
different species living
within a particular
region

3. Fungi
• Mostly multicellular but some unicellular.
• Has a cell wall but does NOT make its own food.
• Heterotrophic
• Change dead organic matter into usable nutrients…
Decomposers
• Ex: Bread mold, mildew, yeast, and mushrooms.

4. • Distinguished from other
kingdoms by:
– Nutrition
– Structural
organisation
– Growth
– Reproduction

5. FUNGI
• COMMON FUNGI
EXAMPLES:
– Mushrooms, yeasts,
molds, morels, bracket
fungi, puff balls

6. • Fungi use extracellular digestion – when enzymes
are secreted outside of their body to digest food
• Most fungi are multicellular
• Fungal spores develop from hyphae
• Many fungi are symbionts with other organisms

7. Absorptive nutrition enables fungi to live as decomposers
and symbionts
• Fungi are heterotrophs that acquire nutrients by
absorption
• Secrete hydrolytic enzymes and acids to decompose
complex molecules into simpler ones that can be
absorbed
• Specialised into three main types:
– Saprobes - absorb nutrients from dead organic
material
– Parasitic fungi - absorb nutrients from cells of living
hosts; some are pathogenic
– Mutualistic fungi - absorb nutrients from a host, but
reciprocate to benefit the host

8. Extensive surface area and rapid growth adapt fungi
for absorptive nutrition
• Basic structural unit of
fungal vegetative body
(mycelium) is the hypha
– Composed of tubular
walls containing chitin
– Provide enormous
surface area: 10cm2
of soil may contain
1km of hyphae with
314cm2 surface area

9. Fungi are adapted to absorb their food from the
environment.
Plants Both Fungi
Autotrophic
(photosynthesize)
Eukaryotic Heterotrophic (absorb
and digest from the
surface they live on for
energy)
Roots Non-motile/ anchored in
soil or structure
Decomposers
1 nucleus per cell Organelles Can have 1+ nuclei per
cell
Cell wall made of
cellulose
Cell Wall Cell wall made of chitin
(carb)

11. 3 Major Features
1.Cell walls
– Made of Chitin
– The same stuff that makes insects’ exoskeleton.

12. 2. Hyphae
• Thin filaments making up the fungus.
• Long, thread-like chains of cells.
• Grow at the tips and branch…
• Mycelium – mass of hyphae

13. Fungal hyphae may be septate or aseptate
• Hyphae of septate
fungi are divided into
cells by crosswalls
called septa
• Hyphae of aseptate
fungi lack cross walls
(coenocytic)
• Parasitic fungi have
modified hyphae
called haustoria,
which penetrate the
host tissue but
remain outside cell
membrane

14. Anatomy of Fungi
– hyphae
– mycellium
– fruiting body
Visible

15. Fungi come in many shapes and sizes.
• Primitive fungi are aquatic and have flagellated spores.

16. Fungi reproduce by releasing spores that
are produced either sexually or asexually
• Usually unicellular, haploid and of various shapes and
sizes
• Produced either sexually (by meiosis) or asexually (by
mitosis)
– In favourable conditions, fungi generally clone
themselves by producing enormous numbers of spores
asexually
– For many fungi, sexual reproduction only occurs as a
contingency- results in greater genetic diversity
• Spores are the agent of dispersal responsible for
geographic distribution of fungi:
– Carried by wind or water
– Germinate in moist places with appropriate substrata

17. Generalised life cycle of fungi
Sexual
Asexual

18. 5 Phyla of Fungi
1. Chytridiomycota - Chytrids
2. Zygomycota – Common Molds
3. Ascomycota – Sac Fungi
4. Basidiomycota – Club Fungi
5. Deuteromycota – Imperfect Fungi

19. 1. Phylum Chytridiomycota
• Mostly marine
• Mostly saprophytes (lives on dead
or decaying organic matter)
• Have flagellated spores

20. 2. Phylum Zygomycota
• Mostly terrestrial.
• Two types of hyphae:
– Stolons – (horizontal) spread across the surface
– Rhizoids – (vertical) digs into the surface

21. 3. Phylum Ascomycota (Sac Fungi)
• Most are multicellular (except for
yeast)
• Most undergo asexual
reproduction
• Largest phylum of Fungi
ascoscarpMorels

22. • Club fungi have fruiting bodies which are club-shaped.
• Most are edible
• reproductive structures called basidia
• Include mushrooms, puffballs, and shelf fungi
4. Phylum Basidiomycota (Club Fungi)

23. 5. Phylum Deuteromycota
Ringworm
•Asexual Reproduction
•Imperfect Fungi
•Do not fit into the commonly established taxonomic classification
•No sexual structures
•Multicellular tissue is similar to the hyphae of sac fungi and club
fungi
•Erect hyphae with asexual spores similar to sac fungi and club
fungi

25. – life cycles may include either sexual or asexual
reproduction or both
• Multicellular fungi have complex reproductive cycles.

27. • All fungi form spores and zygotes.

28. Fungi may be decomposers, pathogens, or mutualists.
• Fungi and bacteria are the main decomposers in any
ecosystem.
– decompose dead leaves, twigs, logs, and animals
– return nutrients to the soil
– can damage fruit trees and wooden structures

29.  Fungi can act as pathogens.
• human diseases include ringworm and athlete’s foot
• plant diseases include Dutch elm disease
• Haustoria – hyphae that penetrate the host so that the
parasitic fungus can absorb nutrients

30. • Fungi can act as mutualists.
– lichens form between fungi and algae
– mycorrhizae form between fungi and plants

31. Lichens
Bioindicators – help show when environmental
conditions are unsuitable.
foliose
crustose

32. dispersal
fragment (cells of
mycobiont and of
photobiont)
cortex (outer
layer of
mycobiont)
photobionts
medulla (inner
layer of loosley
woven hyphae)
cortex
Crustose

33. Leaf-like - foliose
Old Man’s
Beard
Usnea –
fructicose
Erect branching
Lichen
Cladonia rangiferina
fructicose

34. Crustose
foliose
fructicose

35. – relationships form between fungi and some insects
• Fungi can act as mutualists.

36. Fungi are studied for many purposes.
• Fungi are useful in several ways.
– as food
– as antibiotics
– as model systems for molecular biology

37. Fungi and Humans
• Bioremediation – help clean the environment.

38. Fungi and Humans
• Molds
– Penicillium
- Penicillin
- Camembert and
Roquefort
cheeses
– Aspergillus
- Soy sauce
- Soft drinks - citric
acid
• Yeasts
– Saccharomyces
cerevisiae
- Bread, wine and
beer
– Candida albicans
- Infections

39. Some Pathogenic and Toxic Fungi
Zygomycetes
Rhizopus - Food spoilage
Ascomycetes
Aspergillus – sinus, ear,
lung infection
Verticillium sp Plant wilt
Monilinia fructicola-
Brown Rot of Peaches