This document provides information about fungi through text and images. It describes the main characteristics of fungi, including that they are eukaryotic and heterotrophic, absorbing nutrients from dead organisms. It details their structures, including being made of hyphae and having cell walls containing chitin. The document outlines the different phyla of fungi and their characteristics. It also discusses fungi's roles in ecosystems, such as recycling nutrients, being plant parasites, and forming symbiotic relationships in lichens and mycorrhizae.
3. CHARACTERISTICS OF
FUNGI
• eukaryotic
• heterotrophic – secrete enzymes into
food and absorb digested materials
through cell walls
– most are saprophytic – absorb organic
materials from dead organisms, “nature’s
recycler”
• many are microscopic
BACK TO FUNGI HALL
4. STRUCTURE OF FUNGI
• made up of hyphae (filaments),
collectively called mycelium
mycelium
• cell walls contain chitin (also found in
insect and crustacean exoskeletons)
– plant cell walls contain ???
– eubacteria cell walls contain ???
CONTINUED
7. STRUCTURE OF FUNGI
• cells can be coenocytic – have many nuclei or
have separated by septa – “walls”
• range in size from microscopic (yeast) to the
largest organism in the world (Armillaria – 3.1
mi2
)
• some are dimorphic – can change form
based on environmental conditions, can grow as
mycelium in soil or as unicellular organisms in
humans (Histoplasma)
BACK TO FUNGI HALL
8. REPRODUCTION IN
FUNGI
• reproduce both asexually (genetically
identical offspring) and sexually
• most fungi are haploid throughout their
life cycle
• sexual reproduction occurs when
hyphae of different mating types
(+ and -) meet and fuse together
BACK TO FUNGI HALL
17. Rhinocerebral Zygomycosis –
causes lesions of the palate,
face and brain
Conidiobolus coronatis -
causes polyps in the nose
or masses under the skin,
found in tropical areas
CONTINUED
18. •25,000 species
•form a basidiocarp, a reproductive
structure also known as a mushroom!
CONTINUED
19. DEADLY MUSHROOMS
Some Amanita species associated with oak trees
contain alpha-amanitin which works by slowly attacking
RNA polymerase, an enzyme in the liver. It ultimately
affects the central nervous system and kidneys. Death
often results if a liver transplant or other heroic
measures are not performed.
CONTINUED
26. •30,000 species
•believed to have evolved most
recently
•live in salt, freshwater and terrestrial
habitats
•phyla includes morels, powdery
mildews, yeasts and cup fungi
CONTINUED
28. Sexual Reproduction in
Ascomycota
•hyphae of 2 mating strains form gametangia
female - ascogonium male -
antheridium
•gametangia fuse and move into ascogonium, nuclei pair but
do not fuse
•cells divide mitotically, each heterokaryotic hyphae grows
and intertwines to form an ascocarp (reproductive body)
•asci form on the surface of the ascocarp, near the tips of
some hyphae
•each ascus has 2 nuclei that fuse
•each diploid nucleus undergoes meiosis to produce 4 haploid
nuclei
•haploid nuclei divide once by mitosis so that each ascus ends
up with 8 haploid ascospores
•ascus ruptures to release ascospores that germinate
CONTINUED – yes, there is a diagram!
40. •may have helped early plants obtain
nutrients through a symbiotic relationship
•played an important role in plant evolution
460 million years ago
•many fungi are plant parasites responsible
for 15-20% of crop loss yearly
CONTINUED
41. •play an essential role in maintaining
equilibrium in every ecosystem (even the
human body) by recycling nutrients,
breaking down wastes and keeping other
populations in check
•replace essential nutrients that
plants remove from the soil
BACK TO FUNGI HALL
42. wheat rust - produces spores
in barberry plants that then
migrate to wheat fields
CONTINUED
45. •what does each organism get from the relationship ?
•what is the ecological importance of these organisms ?
lichens
BACK TO ECOLOGY
46. fungi provide moist shelter for the algae,
while the algae provide a constant food
supply (through photosynthesis) to their
fungal host
CONTINUED
47. lichens are often the first organisms to
inhabit barren areas (succession),
creating soil by breaking down rock and
adding organic nutrients (from their decay)
lichen growing on
gneiss
CONTINUED
48. •mycorhizzae are symbiotic relationships
between the roots of most plants and
fungi
•the fungi fix nitrogen so that it can be
used by plants, while they use the plants
as a shelter and food source