24.2 Classifications of Fungi

Chytridiomycota

(also, chytrids) primitive phylum of fungi that live in water and produce gametes with flagella

Basidiomycota

(also, club fungi) phylum of fungi that produce club-shaped structures (basidia) that contain spores

Zygomycota

(also, conjugated fungi) phylum of fungi that form a zygote contained in a zygospore

Ascomycota

(also, sac fungi) phylum of fungi that store spores in a sac called ascus

Which of the following statements is true? A basidium is the fruiting body of a mushroom-producing fungus, and it forms four basidiocarps. The result of the plasmogamy step is four basidiospores. Karyogamy results directly in the formation of mycelia. A basidiocarp is the fruiting body of a mushroom-producing fungus.

A basidiocarp is the fruiting body of a mushroom-producing fungus.

Which of the following statements is true? A dikaryotic ascus that forms in the ascocarp undergoes karyogamy, meiosis, and mitosis to form eight ascospores. A diploid ascus that forms in the ascocarp undergoes karyogamy, meiosis, and mitosis to form eight ascospores. A haploid zygote that forms in the ascocarp undergoes karyogamy, meiosis, and mitosis to form eight ascospores. A dikaryotic ascus that forms in the ascocarp undergoes plasmogamy, meiosis, and mitosis to form eight ascospores.

A dikaryotic ascus that forms in the ascocarp undergoes karyogamy, meiosis, and mitosis to form eight ascospores.

Ascomycota: The Sac Fungi

Ascomycota: The Sac Fungi

By ingesting spores and disseminating them in the environment as waste, animals act as agents of dispersal. The benefit to the fungus outweighs the cost of producing fleshy fruiting bodies.

By ingesting spores and disseminating them in the environment as waste, animals act as agents of dispersal. The benefit to the fungus outweighs the cost of producing fleshy fruiting bodies.

The fungi that do not reproduce sexually use to be classified as ________. Ascomycota Deuteromycota Basidiomycota Glomeromycota

By ingesting spores and disseminating them in the environment as waste, animals act as agents of dispersal. The benefit to the fungus outweighs the cost of producing fleshy fruiting bodies.

The most primitive phylum of fungi is the ________. Chytridiomycota Zygomycota Glomeromycota Ascomycota

Chytridiomycota

Section Summary

Chytridiomycota (chytrids) are considered the most primitive group of fungi. They are mostly aquatic, and their gametes are the only fungal cells known to have flagella. They reproduce both sexually and asexually; the asexual spores are called zoospores. Zygomycota (conjugated fungi) produce non-septated hyphae with many nuclei. Their hyphae fuse during sexual reproduction to produce a zygospore in a zygosporangium. Ascomycota (sac fungi) form spores in sacs called asci during sexual reproduction. Asexual reproduction is their most common form of reproduction. Basidiomycota (club fungi) produce showy fruiting bodies that contain basidia in the form of clubs. Spores are stored in the basidia. Most familiar mushrooms belong to this division. Fungi that have no known sexual cycle were classified in the form phylum Deuteromycota, which the present classification puts in the phyla Ascomycota and Basidiomycota. Glomeromycota form tight associations (called mycorrhizae) with the roots of plants.

Members of which phylum establish a successful symbiotic relationship with the roots of trees? Ascomycota Deuteromycota Basidiomycota Glomeromycota

Glomeromycota

The fungi that do not reproduce sexually use to be classified as ________. Ascomycota Deuteromycota Basidiomycota Glomeromycota

Glomeromycota

Members of which phylum produce a club-shaped structure that contains spores? Chytridiomycota Basidiomycota Glomeromycota Ascomycota

Members of which phylum produce a club-shaped structure that contains spores? Chytridiomycota Basidiomycota Glomeromycota Ascomycota

Zygomycota

The Conjugated Fungi

The zygomycetes are a relatively small group of fungi belonging to the Phylum Zygomycota

They include the familiar bread mold, Rhizopus stolonifer, which rapidly propagates on the surfaces of breads, fruits, and vegetables

basidium

club-shaped fruiting body of basidiomycetes

This form of sexual reproduction in fungi is called conjugation (although it differs markedly from conjugation in bacteria and protists), giving rise to the name "conjugated fungi".

conjugated fungi".

Deuteromycota

former form phylum of fungi that do not have a known sexual reproductive cycle (presently members of two phyla: Ascomycota and Basidiomycota)

former form phylum of fungi that do not have a known sexual reproductive cycle (presently members of two phyla: Ascomycota and Basidiomycota)

former form phylum of fungi that do not have a known sexual reproductive cycle (presently members of two phyla: Ascomycota and Basidiomycota)

ascocarp

fruiting body of ascomycetes

basidiocarp

fruiting body that protrudes from the ground and bears the basidia

mycota

is used to designate a phylum

Arbuscular mycorrhizae

mycorrhizae commonly involving Glomeromycetes in which the fungal hyphae penetrate the cell walls of the plant root cells (but not the cell membranes)

Cryptococcus

neoformans causes severe respiratory illness.

Glomeromycota

phylum of fungi that form symbiotic relationships with the roots of trees

ascomyceter life cycle

pic

Zygomycetes play a considerable commercial role. The metabolic products of other species of Rhizopus are intermediates in the synthesis of semi-synthetic steroid hormones.

semi-synthetic steroid hormones.

zygospore

structure with thick cell wall that contains the zygote in zygomycetes

mold

tangle of visible mycelia with a fuzzy appearance

The only class in the Phylum Chytridiomycota

the Chytridiomycetes

the aflatoxins released by fungi of the genus Aspergillus.

the aflatoxins

The chytrids are

the simplest and most primitive Eumycota, or true fungi. Chytrids usually live in aquatic environments