Fungi
The fungi lack photosynthetic
pigments. As a group, they are heterotrophic
and must obtain their food either from dead organic matter (saprophytically) or
from living organisms (parasitically). Approximately 100,000 species have been
described, and these are very widely distributed, particularly on land,
although there are a number of common water-growing species.
What were once fungi have been
divided into six phyla: Myxomycophyta and Chytridomycota (now in kingdom
Protista), Oomycota (now in kingdom Chromista), and Zygomycota, Ascomycota, and
Basidiomycota (the true kingdom Fungi). Classification of the three phyla of
true fungi is controversial and based primarily on their sexual reproduction. A
seventh artificial phylum, Deuteromycota, includes all species for which no
sexual stages are known at present. Mycologists consider it their duty to
discover the sexual stages and classify these species into the natural
phyla...easier said than done. Most are clearly members of Ascomycota and a few
are clearly members of Basidiomycota.
The true fungi produce a
vegetative body which is composed of masses of fine branched filaments often
having a cottony appearance. A single filament is called a hypha, while a mass of hyphae
makes up the mycelium. Mycelia may
form reproductive structures, usually both asexual and sexual. While the
mycelia of different species are very much alike in gross appearance, the
reproductive structures are distinctive.
You will look at a few rather
typical representatives of kingdom fungi. Make a record that will give some
idea of the diversity of form that occurs among the fungi and will point out
some of the differences among the kinds of fungi. You should practice making
life cycle diagrams for these taxa as good practice in understanding their
natural history.
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