They are eukaryotic and heterotrophic, because they lack chlorophyll.
They have a great diversity and range from microscopic yeast to macroscopic mushrooms.
They are multicellular and filamentous, except yeast which is unicellular.
The cell wall of fungi is composed of chitin and polysaccharide.
They have slender thread like structures(individual filaments), called hyphae. The network of hyphae is called mycelium.
Hyphae are continues tube that consists of multinucleated cytoplasm, called Coenocytic hyphae.
The cross walls in hyphae are called septe.
Fungi are heterotrophs and get their food from dead organic matters, hence called as saprophytes.
Some fungi are parasites or symbionts (lichens and mycorrhiza).
Some of the fungi are beneficial (Yeast) whereas, several causes diseases in animals and plants (Puccinia).
They reproduce vegetatively, sexually and asexually.
Vegetative reproduction takes place by fragmentation, fission and budding.
Asexual reproduction is by means of spores called conidia or sporangiospores or zoospores.
Sexual reproduction is by oospores, ascospores and basidiospores. The spores are produced in distinct structures called fruiting bodies.
The sexual cycle of fungi involves three steps,
a) Fusion of protoplasm between two motile or non-motile gametes called plasmogamy.
b) Fusion of two nuclei called karyogamy. It leads to zygote formation.
c) Meiosis in zygote, resulting in haploid spores.
In sexual reproduction, two dissimilar haploid hyphae of compatible type come together and fuse, forming diploid nucleus(2n).
However, in some fungi, fusion of two haploid cells results in dikaryotic stage i.e. two nuclei per cell (n+n), called dikaryon. Later parental nucleus fuse and form diploid nucleus.
During reproduction in fruiting body, meiosis or reduction division occurs, forming haploid spores(n). These spores forms dissimilar thallus called heterothallism.
Classification of Kingdom Fungi
It is classified into various classes based on morphology of the mycelium, mode of spore formation and fruiting bodies.
(i) Phycomycetes
(ii) Ascomycetes
(iii) Basidiomycetes
(iv) Deuteromycetes
Phycomycetes
These are also called as zygomycetes.
The phycomycetes are found in aquatic habitats on decaying wood and moist places.
They are the obligate parasites on plants.
Mycelium is non-septate and coenocytic.
Phycomycetes reproduce asexually by forming motile zoospores or by non-motile aplanospores.
They reproduce sexually by fusion of gametes, resulting in formation of diploid zygospores. In favourable conditions, these zygospores undergo meiosis and produce haploid hypha.
Ex: Rhizopus (Bread mould), Mucor, Albugo
Ascomycetes
They are commonly called sac fungi.
They are either unicellular (yeast) or multicellular (Penicillium).
They are saprophytic or parasitic, some are decomposers.
They have a branched and septate mycelium.
Asexual reproduction is by producing spores called conidia, exogenously on the tip of some hyphae called conidiophores.
Sexual reproduction is by production of sexual spores called ascospores, exogenously in sac like structures called Asci.
The asci are arranged in fruiting bodies called ascocarps.
Ex: Aspergillus, Neurospora, Saccharomyces (yeast)
Basidiomycetes
They are commonly known as Club fungi.
Common forms are mushroom, puffball, bracket fungi etc.
They grow as parasites in the form of rusts and smuts on wood logs, soil and in living plant bodies.
They have branched and septate mycelium.
Vegetative reproduction takes place by fragmentation and asexual spores are generally not found.
Fusion of somatic cells of different strain, leads to plasmogamy. This results in dikaryotic condition, which forms basidium.
Karyogamy and meiosis takes place in the basidium producing four basidiospores.
Haploid basidiospores gives rise to haploid hyphae.
Ex: Agaricus, Ustilago, Puccinia
Deuteromycetes
They are commonly known as imperfect fungi because, only asexual or vegetative phases of these fungi are known.
The mycelium is septate and branched.
They are parasites, saprophytes or decomposers.
They reproduce only by asexual means by producing conidia.
Ex: Alternaria, Colletotrichum, Trichoderma
.
They have a great diversity and range from microscopic yeast to macroscopic mushrooms.
They are multicellular and filamentous, except yeast which is unicellular.
The cell wall of fungi is composed of chitin and polysaccharide.
They have slender thread like structures(individual filaments), called hyphae. The network of hyphae is called mycelium.
Hyphae are continues tube that consists of multinucleated cytoplasm, called Coenocytic hyphae.
The cross walls in hyphae are called septe.
Fungi are heterotrophs and get their food from dead organic matters, hence called as saprophytes.
Some fungi are parasites or symbionts (lichens and mycorrhiza).
Some of the fungi are beneficial (Yeast) whereas, several causes diseases in animals and plants (Puccinia).
They reproduce vegetatively, sexually and asexually.
Vegetative reproduction takes place by fragmentation, fission and budding.
Asexual reproduction is by means of spores called conidia or sporangiospores or zoospores.
Sexual reproduction is by oospores, ascospores and basidiospores. The spores are produced in distinct structures called fruiting bodies.
The sexual cycle of fungi involves three steps,
a) Fusion of protoplasm between two motile or non-motile gametes called plasmogamy.
b) Fusion of two nuclei called karyogamy. It leads to zygote formation.
c) Meiosis in zygote, resulting in haploid spores.
In sexual reproduction, two dissimilar haploid hyphae of compatible type come together and fuse, forming diploid nucleus(2n).
However, in some fungi, fusion of two haploid cells results in dikaryotic stage i.e. two nuclei per cell (n+n), called dikaryon. Later parental nucleus fuse and form diploid nucleus.
During reproduction in fruiting body, meiosis or reduction division occurs, forming haploid spores(n). These spores forms dissimilar thallus called heterothallism.
Classification of Kingdom Fungi
It is classified into various classes based on morphology of the mycelium, mode of spore formation and fruiting bodies.
(i) Phycomycetes
(ii) Ascomycetes
(iii) Basidiomycetes
(iv) Deuteromycetes
Phycomycetes
The phycomycetes are found in aquatic habitats on decaying wood and moist places.
They are the obligate parasites on plants.
Mycelium is non-septate and coenocytic.
Phycomycetes reproduce asexually by forming motile zoospores or by non-motile aplanospores.
They reproduce sexually by fusion of gametes, resulting in formation of diploid zygospores. In favourable conditions, these zygospores undergo meiosis and produce haploid hypha.
Ex: Rhizopus (Bread mould), Mucor, Albugo
Ascomycetes
They are either unicellular (yeast) or multicellular (Penicillium).
They are saprophytic or parasitic, some are decomposers.
They have a branched and septate mycelium.
Asexual reproduction is by producing spores called conidia, exogenously on the tip of some hyphae called conidiophores.
Sexual reproduction is by production of sexual spores called ascospores, exogenously in sac like structures called Asci.
The asci are arranged in fruiting bodies called ascocarps.
Ex: Aspergillus, Neurospora, Saccharomyces (yeast)
Basidiomycetes
Common forms are mushroom, puffball, bracket fungi etc.
They grow as parasites in the form of rusts and smuts on wood logs, soil and in living plant bodies.
They have branched and septate mycelium.
Vegetative reproduction takes place by fragmentation and asexual spores are generally not found.
Fusion of somatic cells of different strain, leads to plasmogamy. This results in dikaryotic condition, which forms basidium.
Karyogamy and meiosis takes place in the basidium producing four basidiospores.
Haploid basidiospores gives rise to haploid hyphae.
Ex: Agaricus, Ustilago, Puccinia
Deuteromycetes
The mycelium is septate and branched.
They are parasites, saprophytes or decomposers.
They reproduce only by asexual means by producing conidia.
Ex: Alternaria, Colletotrichum, Trichoderma
.
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