Download Chapter 31: Kingdom Fungi Campbell Text 7th Ed. Pgs: 608 – 623

I.
II.
Chapter 31: Kingdom Fungi
Campbell Text 7th Ed. Pgs: 608 – 623
About 500 MYA Fungi (Mycota) begin to colonize the land to break down the abundant dead plant material that exists.
A. This Kingdom is composed mainly of soil dwelling decomposers mostly.
B. The Kingdom evolved from unicellular flagellated protists.
1. The protists belong to the group of Opisthokonts – means ”Flagellated ones”.
C. Fungi only resemble plants; but are more closely related to animals.
1. DNA signature sequencing in the small sub-unit of a ribosome and genomics agrees.
a. Animals and Fungi would have separated 1.5 Billion Years ago.
2. Fungi are Heterotrophe by Absorption using exoenzymes. (Animals are heterotrophe by ingestion.)
3. Fungi cell walls composed of Chitin. (Same substance found in the exoskeleton of Arthropods.)
a. Remember, Plant cell walls are composed of Cellulose.
D. Most Fungi have symbiotic relationship with plants roots. (Referred to as mycorrhizae.)
1. The Fungi help to increase the surface area for water uptake by the roots. The plant provides sugars for food.
2. Endomycorrhiza (The fungus enters into the root cells of the plant.)
3. Ectomycorrhizae (The fungus covers over the surface of the root of the plant.)
Fungi Body Structure
A. Hyphae (These are tubular filaments.)
1. Hyphae are intertwined to form a Mycelium. (means “Fungus body”)
a. The mycelium extends above and below ground.(Fig:31.2)
2. Two types of hyphae exist:
a. Septated - These hyphae have cell septa. (“septa” means “partitions”.) (Fig: 31.3)
b. Coenocytic - These hyphae are without partitions. (They are multinucleated.)
3. Haustoria – These are hyphae that are for capturing prey by impaling them. (Fig: 31.4) (Think hostile
haustoria.)
4. Fungi can grow extremely fast. (This reduces competition.) (They just need moisture (rain) to grow.)
III. Fungal Life Cycles (Fig:31.5)
A. Majority of the life is spent as HAPLOID asexual organisms.
1. This allows the organism to reproduce much faster and colonize a dead organism for food and reduce
competition.
2. Fungi use the diploid state to create variation. (Remember, variation helps with survival in a changing
environment.
B. ALL sexual reproduction, for ALL types of fungus, involves three steps:
1. Plasmogamy (This is the fusion of cytoplasm.) (+=male; - =female)(The “female” is signaled by the release of
pheromones from the “male”.)
a. This fusion together of hyphae results in heterokaryon (Means “different nuclei”) or Dikaryotic (Means
“two nuclei”).
2. Karyogamy (Means the fusion of nuclei) This makes the hyphae now 2n (Diploid) in genetic content.
3. Meiosis of the diploid zygote to return to a haploid(n) state.
a. Variation has been created due to crossover in Prophase 1 and Segregation of Chromosomes in Anaphase.
IV. Classification of Fungi
A. Most fungus are classified according to the SEXUAL reproductive structure they produce.
B. Six Major Phylum exists
1. Chytridomycota (The sexual structure is the Chytrids.)(Fig;31.10)
a. Produce flagellated spores called zoospores.(Similar to sperm of the animal kingdom.)
2. Zygomycota (The sexual structure is the Zygosporangium.)(Fig:31.12)
a. Examples - Mycorrhizae, Rhizopus stolonifer (black bread mold), Penicillium (green bread mold)
3.
4.
5.
6.
Glomeromycetes
a. Most are endomycorrhizae called arbuscular. (A tree shaped connection with plant cells.)
Ascomycota (The sexual structure is the ascus - means “sac”.)(Figs: 31.16 and31.17)
a. Ascus are found on the large ascocarp mycelium.
b. Spores are small and dust like structures called Conidia.
c. Examples - Lichens, plant pathogens, mycorrhizae, yeast
Basidiomycota (The sexual structure is the Basidium - means “club”.) (Figs: 31.18,31.19, and 31.20)
a. Basidium found on the large Basidiocarp mycelium.
b. These fungi are important decomposers. (They can break down lignin of plant cell walls.)
c. Examples - Mycorrhizae, food mushrooms, Fairy Rings, Death Cap, Toad Stool, Puff balls
Deuteromycota (These are the Imperfect Fungi - No known means of sexual reproduction; thus imperfect.)
a. Humans use Yeast for bread and alcohol production.
b. Candidia albicans – this fungus causes a yeast infection of the vagina. (Mycosis – means “a fungal
infection”)(A Fungicide is prescribed for treatment.)
V. Ecological Impact of Fungus
A. They are important DECOMPOSERS. (A.K.A. Saprobes) (They recycle vital nutrients back to the environment.)
B. Some fungus are Plant pathogens – wheat rust, corn smut, Dutch Elm Disease, Chestnut Blight.
C. Some fungus are human pathogens – ring worm, athletes foot, jock itch, yeast infections, dandruff.
D. Some fungus are used as medicines and food.