kingdom fungi chapter 22
DESCRIPTION
Characteristics of Fungi All fungi share 3 characteristics: Fungi have threadlike bodies Fungal cell walls contain chitin CHITIN – a tough carbohydrate that is found in the hard outer covering of insects and other organisms Fungi are heterotrophicTRANSCRIPT
Kingdom Fungi
Chapter 22
Characteristics of Fungi
All fungi share 3 characteristics: Fungi have threadlike bodies Fungal cell walls contain chitin
CHITIN – a tough carbohydrate that is found in the hard outer covering of insects and other organisms
Fungi are heterotrophic
Body Structure Fungi have bodies made of threadlike
strands called HYPHAE. Hyphae form a tangled mass often
many meters long called a MYCELIUM.
In some fungi, hyphae also form root-like structures called RHIZOIDS
Obtaining Nutrients Fungi release enzymes that break down
organic and inorganic matter into nutrients. Fungi absorb the nutrients across their
cell walls. SAPROBES – fungi that absorb nutrients
from dead organisms PARASITES – fungi that absorb nutrients
from living hosts
Reproduction Most fungi reproduce sexually and asexually
In SEXUAL reproduction, spores are produced by meiosis Allows for genetic diversity Specialized structures (like mushrooms) for
sexual reproduction In ASEXUAL reproduction, spores are produced by
mitosis Allows for rapid reproduction
Fungi that do not have an observed sexual stage are grouped together and called IMPERFECT FUNGI
Reproduction
Yeast and Mold The words “yeast” and “mold”
refer to SPECIFIC STAGES of the life cycle that are shared by several types of fungi
YEAST Common name for fungi that
exist in a unicellular stage Reproduce asexually by budding
MOLD The rapidly growing, asexually
reproducing stage of some types of fungi
Groups of Fungi Chytrids (Family CHTRIDIOMYCOTA)
A group of aquatic fungi that provide clues about the evolution of fungi
Mostly unicellular saprobes that feed on protists, plants, animals, and other fungi
Common parasites of aquarium fish
Believed to have been the cause of the decline in amphibians in the wild
Groups of Fungi (cont.) Zygote Fungi (Family ZYGOMYCOTA)
Named for sexual reproductive structures that produce zygotes inside a tough capsule (called a ZYGOSPORANGIUM)
Asexual reproduction by spores is most common in zygote fungi
Example: RHIZOPUS – bread mold; can also live in soil
Groups of Fungi (cont.) Sac Fungi (Family ASCOMYCOTA)
ASCUS – a sac-like reproductive structure that produces spores
Usually reproduce asexually Asexual spores called
CONIDIA form by mitosis on specialized hyphae called CONIDOPHORES
Groups of Fungi (cont.) Club Fungi (Family BASIDIOMYCOTA)
Include mushrooms, toadstools, puffballs, jelly fungi, shelf fungi, rusts, and smuts
BASIDIUM – a club-like sexual reproductive structure that produces spores
Sexual reproduction is most common – usually form rings Basidiocarp – reproductive
structure (the “actual” mushroom)
Fungal Partnerships Fungi form mutualistic symbiotic
associations to form lichens and mycorrhizae
LICHEN An association between
fungus and a photosynthetic partner such as cyanobacteria or algae
MYCORRHIZA An association between
fungi and the roots of nearly all plants
Fungi and Industry, Ecosystem, and Disease
(cont.) Fungi are used for food, medicines,
research, alternative fuels, and pest control. FOOD: mushrooms; blue cheese; yeast in
baking, brewing, and winemaking; produce citric acid found in soft drinks and candy
MEDICINES: produce antibiotics like penicillin; bread mold makes cortisone (used to treat skin irritations); yeast has been used to make vaccines for Hepatitis B
ALTERNATIVE FUELS: yeast produce gasohol (gasoline alternative)
FUNGAL INSECT PESTICIDES: reduces the need for harmful/toxic pesticides on crops
Fungi and Industry, Ecosystem, and Disease
Fungi play important ecological roles by decomposing organic matter and by breaking down and absorbing minerals from rocks and soil.
Fungi cause disease by absorbing nutrients from host tissues and by producing toxins. Fungi can grow on and inside tissues of the body
and therefore can be difficult to cure DERMATOPHYTES – fungi that infect the skin and
nails(ex: Athlete’s Foot, Toenail Fungus, and Ringworm) Yeast Infections – occur on reproductive organs and
mouth Toxins produced by fungi can cause vomiting,
diarrhea, liver damage, cancer, and even death