Plants, Fungi, and the Colonization of Land: Fungi

1. Absorptive heterotrophic eukaryotes--digest their food externally and absorb the nutrients
2. Most consist of a mass of thread-like hyphae making up a mycelium
3. Hyphae have a huge surface area to secrete digestive enzymes and absorb food

1. Separated by cross-walls with pores large enough for ribosomes, mitochondria and nuclei to cross
2. Some are multinucleate without cross-walls
3. Surrounded by cell wall with chitin

1. Most can reproduce sexually and asexually
2. Both types involve the production of spores in a fruiting bodythat projects above the mycelium

1. Produce huge numbers of asexual spores
2. Each spores can germinate to form a new fungus

1. Sexual fusion of haploid hyphae leads to a heterokaryotic stage where cells contain two genetically distinct haploid nuclei
2. Hours or centuries may pass before parental nuclei fuse to form a short-lived diploid phase
3. Zygotes undergo meiosis inside specialized reproductive structures and disperse haploid spores

1. Sexual reproductive structures used to classify fungi
2. Fungi with no known sexual stage are called imperfect fungi
3. Fungi most likely evolved from an aquatic flagellated ancestor shared with animals

1. Chytrids
2. Zygomycetes (zygote fungi)
3. Glomeromycetes
4. Ascomycetes (sac fungi)
5. Basidiomycetes (club fungi)

1. Earliest lineage of fungi
2. Have flagellated spores

1. Zygote fungi form resistant zygosporangia in which haploid spores form by meiosis
2. Group includes black mold

1. Form mycorrhizae in which invasive hyphae branch into treelike arbuscules within plant roots

1. Sac fungi form sac-like asci which produce sexual spores
2. Range in size from yeasts to morels and cup fungi
3. Some form lichens in association with green algae or cyanobacteria

1. Club fungi are mushrooms, puffballs and shelf fungi
2. Have club-shaped spore-producing structures called basidia
3. Important forest decomposers

Causes mycoses
2. Human infections: athletes foot, yeast infections, nail infections
3. Systemic mycoses are rare but serious fungal infections that spread through the body from inhaled spores

1. Termites, citrus mites, aphids
2. Gypsy moths

1. Consist of algae or cyanobacteria within a fungal network
2. Important pioneers on new land where they help to form soil
3. Sensitive to air pollution