Fungi Phyla
Zygomycota
Including fast-growing molds, zygomycetes are a decomposer
of dead organisms and a parasite of living organisms. However, some may form
commensal, symbiotic relationships with animals. They usually reproduce
asexually, by producing hundreds of haploid spores through mitosis. But when
environmental conditions deteriorate, they reproduce sexually. This is done by
the production of haploid nuclei when two neighboring mycelia of different
mating types meet. Meiosis occurs, and a diploid nuclei is formed. A sporangium
germinates, which produces haploid spores that will mature into new mycelia. Zygomycetes
are a major agricultural and economic cost to humans everywhere, as they cause
foods to rot during storage. An example is Phycomyces blakesleeanus.
|
Glomeromycetes
Glomeromycetes
were thought to be zygomycetes, since they share the same reproductive cycle
and many other traits. But DNA sequence analysis shows they form a separate monophyletic
clade from the zygomycetes. Glomeromycetes are a major agricultural and
economic benefit for humans. Nearly 90% of plants have formed a mutualistic
relationship with them. Glomeromycetes form arbuscular mycorrhizae, where the
tips of the hyphae push into plant root cells. The surface area of the roots
are vastly increased, with more water and other nutrients being absorbed by the
plant, ensuring healthier and more prosperous plants to harvest. An example is Gigaspora margarita.
|
Ascomycota
Ascomycetes vary from unicellular yeasts to complex fungi.
Unique to their phylum is the production of spores in the sac-like asci during
sexual reproduction. For asexual reproduction, they form external spores call
conidia. Ascomycetes form a diverse set of mutualistic relationships, with
cyanobacteria or green algae to form lichen, mycorrhizae with plants or in the
mesophyll of leaves where they emit toxic compounds to drive out insects. An
important commercial value to humans is that ascomycetes are decomposers of dead
material and waste, so they help keep the earth clean. An example is Sarcoscypha coccinea.
|
Basidiomycota
Basidiomycetes can be either helpers or hurters. By forming
mutualistic relationships with plants, they greatly increase surface area and
water intake. But they can also be destructive plant parasites, like the rusts
and smuts. Unique to Basidiomycetes is their long-lived dikaryotic mycelium. Fruiting
bodies are called basidiocarps, and they may release up to a billion basidiospores.
They have major economic value to humans, as they are best at decomposing
lignin, an important protein in wood. Wood is normally hard to rid of, but
basidiomycetes aid us in doing so. An example is Macrolepiota procera.
|
Click on the following link to learn about the Kingdom Plantae: