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Grade 11 University Biology – Unit 1 Diversity of Life
Fungus Kingdom
Section 3.3 (Pages 105-110)
Fungus (plural fungi) is a
stationary, heterotrophic
eukaryotic organism
whose cell walls contain
chitin.
Some, such as yeast, are
unicellular.
Most multicellular fungus
have the same basic
structure (see Figure
3.16 on Page 105 and
the illustration opposite)
 The main
structure is the
hyphae (singular
hypha). It
consists of
multicellular,
thread-like
filaments
 Mycelium (plural
mycelia) is a complex, net-like mass of branching hyphae. Mycelium is found in the soil and
other nutritious substances (e.g., dead wood)
 Fruiting body, occurring above ground, is the spore producing reproductive structure
DNA links fungus to animals
Fungus release enzymes that break down food external to their bodies. The nutrients are absorbed
through the fungus cell membranes.
Fungus can be classified by the four different ways they obtain nutrients (see Table 3.4 on Page 106).
 Parasitic – Absorb nutrients from living cells of a host organism. Commonly, the host eventually
dies and the fungal fruiting bodies emerge to produce new spores
 Predatory – Soil fungi whose mycelia trap prey
 Mutualistic – Form partnerships with other organisms, and both organisms benefit from the
relationship
 Saprobial – Feeds on a dead organism or organic wastes.
They are decomposers so they recycle nutrients in an
ecosystem
Fungal Reproduction
 Both sexual and asexual reproduction
 Asexual can be spore production, budding or fragmentation
 Produced by fruiting bodies, single-celled spore surrounded
by a protective cell wall are produced via sexual
reproduction. The spores are released to be spread by wind
or water. If the spore lands in a favourable habitat, it may
grow and mature.
Fungal Classification
Fungi are also classified into five groups based on reproduction and the structure of the fruiting body.
Fungi Imperfecti (Phylum Deuteromycots)
 Reproduce asexually
 Example is Penicillium
Chytrids (Phylum Chytridomycota)
 Unicellular
 Aquatic (marine or freshwater)
 Spores have flagella
 May be parasitic or saprobial
Zygospore Fungi (Phylum Zygomycota)
 Multicellular
 Terrestrial
 Example – common mould, Rhizopus (bread mould)
 Zygospore – Diploid structure that develops after two haploid hyphae of opposite types combine
and fuse their nuclei (…usually occurs during unfavourable life conditions). It remains dormant
until good growing conditions occur.
Sac Fungi (Phylum Ascomycota)
 Develop small finger-like sacs called asci (singular ascus) to make spores during sexual
reproduction
 Also single-celled yeasts that reproduce by budding
Club Fungi (Phylum
Basidiomycota)
 Examples are
mushrooms
and puffballs
 These
structures are
short-lived
fruiting bodies
that release
spores called
basidiospores
 Structures are
called basidia
(singular
basidium)
Lichen
 An organism that results from a mutualistic relationship between a fungus and a photosynthetic
plant or alga.
 Called a composite organism
 Able to survive in extreme conditions (e.g., extreme cold)
Kingdom Fungi – Key Information
 Due to morphological similarities, once considered part of the
Plant Kingdom
 Diverged into separate kingdom about 1 BYA
 Worldwide distribution / Live in a variety of environments
 Five different Groups
Key Characteristics
 Multi-cellular
 Eukaryote (e.g., membrane bound nucleus)
 Cell wall and other organelles (…however, NO chloroplasts)
 NO mechanism for locomotion – Thus, stationary
 Heterotrophic (i.e., cannot produce own energy)
 Lack efficient structures or methods to transport water and
minerals – Thus, size is limited
Unique Features
 Some species grow as single-celled yeasts that reproduce by
budding or binary fission
 Fungal cell wall is composed of glucans and chitlin
(…polysaccharide and derivative of glucose, respectfully, that
help form barrier between cell and environment)
 Evolved to use a wide range of organic substances for growth
including nitrate and ammonia
 Break down food external to their bodies
Reproduction
 Asexual (no diversity) or sexual (created diversity)
 Both methods use spores
 At different life stages, haploid (1/2 number of chromosomes)
and diploid (full number of chromosomes) are produced
 Specialized structures develop to support spore dispersal