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Fungi
By: Sami and Sandie
What are Fungi?
 Fungi are heterotrophs
 They cannot make their own food
 They do not ingest their food, rather, they absorb nutrients
from the environment outside of its body
What do Fungi look like?
 The most common body structures are multicellular
filaments and single cells (such as yeast).
 Multicellular:
 Constructed out of tiny filaments called hyphae
 Cells that are long and thread-like and are connected end to end.
 Hyphae produce sporocarp which creates the mushroom structure
 Woven mat called a mycelium located at their base
 Feeding network of a fungus
 Hypha are divided by the septa
 Cell walls built out of chitlin
•
Carbohydrate
What are the functions of the
Fungi’s structure?
 The wide structure of the
mycelium allows for a lot of
absorption and for quick growth
 The septa usually have pores
large enough to allow for
ribosomes, mitochondria, and
nuclei to flow from cell to cell
 In parasitic fungi, hyphae are
mortified as haustria
 Adapted for preying on animals.
How do Fungi reproduce?
 Have two choices: asexual or sexual reproduction
 Asexual:
 Zoospores and autospoors located in the sporangia swim
away and latch onto new areas to form new chytrids
 Sporangia: main cell body
 Chytrid: type of fungi. The oldest.
 Sexual:
 The sporangia produces structures similar to asexual
zoospores that fuse with zoospores from other sporangia to
form a diploid zygote.
 Must come into direct physical contact to have any effect
What are the steps of the sexual
reproduction of fungi?
 Begins when hyphae from two mycelia release sexual
signaling molecules called pheromones.

When the hyphae meet, they fuse together.
 The union of the cytoplasm of the two mycelia is regarded
as plasmogamy.

At this point the mycelium are considered to be heterokaryons
(fused mycelium are still genetically different)
 The next stage is called karyogamy and in this stage, the
haploid nuclei contributed by the two parents fuse together.

At this point the fungi is considered a zygote.

This is the only diploid stage.
 After karyogamy, the cell continues onto meiosis and
germination.
What is the basic life cycle of a
fungus?
What is the origin of fungi?
 There is much evidence that fungi evolved from a
flagellated ancestor
 Due to similarities in genetic sequences, fungi are said
to be related to protists, suggesting that the earliest
ancestor was unicellular.
What type of fungi is the oldest
in regards to modern fungi?
 The oldest ‘modern’ fungi
found are those of chytridlike forms from Russia
 They are considered to be the
sister group to fungi alive
today
 They’re aquatic and not
terrestrial which means fungi
probably got started in water.
 They have flagellated gametes
(tails) and no other fungi have
this

Trait would have been lost
 Cell walls are made up of
both chitin and cellulose
 They have flagellated spores
called zoospores
In theory, what type of species of
fungi came next?
 The Zygomycota are the second oldest classification of fungi.
 They were thought to be very closely related to the aquatic
chrytids but a vast difference in traits contradicted this

Zygotocota fungi lack flagellated gametes and spores and have a
different composition of cell walls
 An example of a common zymycota is bread mold
What followed Zygomycota?
 Glomeromycota follow Zygomycota in time on the
cladogram.
 Very closely related to zygomycota except for the fact that
they have hyphae that push into plant roots and share
mutualistic partnerships with plants
What followed Glomeromycota?
 Ascomycota followed Glomeromycota in regards to time
on the cladogram.
 Their primary difference is that of the production of spores
in saclike asci (which is why their nickname is sac fungi)
 They are usually found to be decomposers but some are
parasitic.
What followed Ascomycota?
 Basidiomycota followed ascomycota in regards to time
on the cladogram
 This is what typically comes to min with the mention of
fungi (mushrooms!!!)
 The club-like shape of the mushroom comes from the
basidium to which is where the sexual reproduction stage of
karygamy occurs.
 They are known to be important decomposers of wood and
other plant material
Fungi as Decomposers?
Fungi as Mutualists?
Fungi as a Parasite?
 https://www.youtube.com/watch?v=XuKjBIBBAL8
What’s the ecological
significance?
 Ecosystem depends on decomposers and symbiontes
 Dead material is recycled and returned to the soil
 Without fungi, the world would be covered in alyer of dead
plants and animals
 Some fungi are parasitic
 Help to maintain population by devouring upon particular
types of plants and animals
 Often used in place of chemical pesticides to protect crops
 Encourages the growth of plants (specifically crops)
 Humans consume several types of fungi as a food source
What’s the economical
significance?
 Commercial importance in food and drugs
 Medicine:
 Penicillin (the first antibiotic) is derived from a common fungus
called Penicillium.
 Some fungi that parasitize caterpillars has chemical compounds
that have be isolated and used in treatment for cancers.
 Food:
 Fungi is used to aid in the growth of crops
 Natural protection of crops from pests
 Direct consumption by humans (ex: Portobello Mushrooms)