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Fungi are multicellular eukaryotic
heterotrophs that do not ingest their food but
rather absorb it through their cell walls and
cell membranes after breaking it down with
powerful digestive enzymes.
Fungi may live as saprophytes (obtain
nutrients from dead organisms), symbionts
(work with a mutually reciprocal relationship
with a host), or parasites and, together with
bacteria, are the major decomposers in the
environment.
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Have cell walls made of chitin (same material is
found in the skeletons of arthropods)
Are made up of many tiny filaments called
hyphae tangled together into a thick net-like
mass called a mycelium (is the vegetative part of
a fungus consisting of a mass of branching
threadlike hyphae that exists below the ground
or within another substrate.). This structure is
well suited to absorbing food as it has a very
large surface area (10 cubic centimeters of soil
may contain upwards of 1 kilometer of hyphae).
The hyphae may be divided by cross walls or they
may be coenocytic (lack cell walls)
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Most fungi are able to reproduce both sexually
and asexually
Sexual Reproduction: two hyphae of different
mating types each form a gametangium (organ in
which gametes are produced). The two
gamatangia fuse and genetic material is
exchanged.
Asexual Reproduction: Production of spores or
fragmentation of hyphae (budding and cell
division in yeast.
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Fungi are classed according to their methods
of reproduction and their basic structure
which, due to recent molecular studies,
places them closer to animals than plants.
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Very closely related to the plant like protists
Form a white fuzz on aquarium fish or on
organic matter sitting in water
Only phylum with flagellated spores during
sexual reproduction.
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Terrestrial fungi can grow on meat, cheese,
and bread and also contain those fungi that
can form mycorrhizae (A fungus that grows in
association with the roots of a plant in a
symbiotic or mildly pathogenic relationship)
Spores produced in sporangia (an enclosure
in which spores are formed) during asexual
reproduction.
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Sexual reproduction occurs when two hypha
from different mating types fuse together.
Gametes are formed in gametangia and then
fuse to form a thick walled, very resistant
zygospore (a thick walled resting cell) which
can be displaced by the wind and remain
dormant until conditions become favorable.
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Sexual reproduction involves the formation of
a tiny sac called an ascus that produces
ascospores.
Yeasts reproduce asexually by cell division
and budding. Also sexually with the
formation of ascospores (which is found in
the form of dry powder in bakers yeast to
make bread)
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Contains over 30, 000 members including
yeast, truffles, powdery mildews, and the
fungi that form symbiotic associations with
cyanobacteria or green algae to create lichen.
Asexual spores called conidia are produced at
the tips of specialized hyphae called
conidiophores (non motile spores)
Penicillium mold
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Includes mushrooms and shelf fungi (which are
the visible fruiting bodies of the fungi), puffballs,
and the plant parasites called rusts and smuts.
Mushrooms are a mass of tightly packed hyphae
with a cap that contains spore producing
structures called basidia which line the gills of
the cap. A single mushroom can produce a
billion basidospores.
Mushrooms can form overnight when the
cytoplasm of thousands of hyphae in the soil
stream into the mushroom.
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“Fairy Rings” form as the mycelia from the fungi
spread out from a central location. As the younger
hyphae on the outside extend out, the older parts
die as nutrients are exhausted from the soil which
forms the ring pattern. The mushrooms form on
the outside of the mycelia forming the ring pattern
Unfortunately there is no rule to follow to tell the
difference between a poisonous mushroom and a
non-poisonous mushroom.
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Imperfect is a botanical term referring to a
lack of sexual reproduction.
Includes Fungi that cannot be placed into any
other phyla. The fungi responsible for
athlete’s foot, ringworm and other skin
conditions fit into this phyla. These fungi are
also responsible for several plant diseases.
Recall - Phylum Chrysophyta: Golden Protists
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Two algae in this phylum – yellow-green algae
and golden-brown algae.
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Contain one or two gold-green chloroplasts
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Some have flagella
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Reproduce both sexually and asexually and
although usually solitary, they can live in
threadlike colonies
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Very thin leaf like structures to allow for
exchange of nutrients and gasses with
environment – not concerned about drying
out.
No specialized tissues for transport –
diffusion all over body of plant
No need for stem like supporting structures –
supported by the buoyancy of water
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Because water absorbs much of the energy
from the sunlight, algae have evolved
different forms of chlorophylls a, b, c, and d –
which absorb different parts of the light
spectrum.
Algae also have evolved accessory pigments
which absorb different wavelengths of light
than chlorophyll absorbs.
Habitat
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Aquatic or semi-aquatic
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Found in fresh water (ponds, lakes streams etc)
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Found in marine areas (floating, submerged,
intertidal)
Terrestrial forms grow on many moist surfaces
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Many unicellular types and some Multi
cellular types
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Filaments
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Large “leafy” types
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Thin – most cells are in contact (or close to)
the environment
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Multicellular – organisms with different kinds of
cells each performing specific functions
(vegetative cells, holdfast, sporangium,
gametangium antheridium/oogonium (produce
sperm/egg for algae) etc…) – division of labour
Alteration of generations – sporophyte and
gametophyte plants – switching back and forth
between the production of diploid and haploid
cells.
Gametes fuse to form spores (sporophyte) which
are dispersed to undergo meiosis to form new
gametophytes.
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Diffusion of raw materials into the cells
Some intracellular conduction (eg. Fucus) –
movement of material between cells.
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Flagella
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Holdfast
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Air bladder – brown algae
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Asexual – binary fission, zoospores,
fragmentation
Sexual
Isogamy – gametes are identical
to each other and swim to each
other
Oogamy – definite egg and
sperm – sperm motile – egg not
◦ Spirogyra – movement of gamete through tube
◦ Any cell can form gametes  specialized cells
which form gametes
◦ Alteration of generations – more than one free
living stage of the organism
(saporophyte/gametophyte)
• Single celled green algae in
ponds, ditches and wet soil –
have an eye spot to detect light.
Chlamydomonas
• Large cup shaped chloroplast
with a pyrenoid (organelle) to
synthesize and store starch.
• No large vacuoles that are found
in land plants but rather
contractile vacuoles that are
found in the protists
• Cell wall that does not contain
cellulose.
Colonial Green Algae.
Gonium - colonial algae composed of 4 32 cells. While they are living together each
cell functions independently.
Volvox – colonial algae from between 500
to 50000 cells connected by strands of
cytoplasm allowing them to communicate
(ie push/pull when they swim). Almost all
cells are identical except for a few that are
specialize for reproduction and produce
gametes.
Spirogyra and Oedogonium – threadlike green
algae.
• Form long threadlike colonies called
filaments that have cells stacked on each
other.
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Fresh water algae that can reproduce
asexually through fragmentation.
Oedogonium can reproduce sexually by
producing two specialized reproductive
cells. This species utilizes holdfast cells to
anchor to the bottom of a lake.
Ulva – multicellular green algae that also
utilize holdfast cells to anchor to the rocks on
the coastline of marine environments.
Fucus (see tank), Giant Kelp
Utilizes alterations of generations and
heterogamy
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Spends most of its life in the haploid stage and
reproduces asexually by mitosis in favorable
conditions.
Can reproduce sexually in unfavorable condtions
◦ Haploid cells continue to undergo mitosis but produce
gametes instead of zoospores.
◦ Produce gametes that appear identical (isogamy). The
gametes gather in large groups, pair, join flagella and
spin in the water shedding their cell walls to fuse and
form a diploid zygote (fusing of gametes = syngamy)
◦ When conditions are favorable again the zygote divides
by meiosis and the flagellated haploid cells swim mature
and reproduce asexually.
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Utilizes alteration of generations in which the
haploid and diploid stages are multicellular
plants.
◦ Diploid plant – sporophyte (spore producer)
◦ Haploid plant – gametophyte (gamete producer)
 Has two different types of gametophytes that produce
different gametes (heterogamy)
 When the two gametes fuse it doesn’t rest but rather forms
a diploid multicellular sporophyte.
 Specialized cells reproduce asexually by meiosis and release
haploid zoospores.
 Zoospores divide by mitosis to form two different types of
gametophyes.
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Utilizes both alteration of generation and
heterogamy.
The egg is large and cannot swim whereas
the sperm is flagellated and swims
Resembles land plants in that it is missing the
multicelluar haploid gametophyte. The
diploid sporophyte plant is the only
multicellular part of the life cycle.