BIO 102 DIVERSITY OF FUNGI
BIO 102 PLANT DIVERSITY,
LECTURE NOTE BY DR. BUP OYESIKU,
DEPT OF PLANT SCIENCE AND APPLIED ZOOLOGY.
MODIFIED BY Admin
INTRODUCTION
Fungi belong to the kingdom "fungi" in taxonomy. Most fungi consist of mainly eukaryotic unicellular organisms. They are non photosynthetic, and majorly terrestrial, with a few aquatic (water molds). They are saprophytic, being primary decomposers in any ecosystem, and are equipped with a powerful resource of enzymes which break down complex organic molecules. The study of fungi is called MYCOLOGY.
REPRODUCTION
Generally fungi reproduce via vegetative, asexual or sexual means.
1) The most common form of vegetative means is FRAGMENTATION of the HYPHAE ( any of the long, threadlike filaments of fungi mycelium).
2) Asexual reproduction is by SPORE formation. Spores are produced by special bodies called SPORANGIA (or CONIDIA ) that bear conidiogenous ( spore producing ) cells. Sometimes sexual spores are produced and these act as gametes in sexual reproduction.
3) Sexual reproduction occurs often. A large number of fungi reproduce sexually by fusion of haploid sexual gametes to form a diploid zygote.
GENERAL CHARACTERISTICS
True fungi have the following characteristics;
1) Rigid cell walls made of chitin 2) Glycogen as the basic form of storage polysaccharide 3) Almost all fungi produce spores (CRYPTOGRAMS) 4) All fungi are NON MOTILE in their life cycle 5) All fungi are non photosynthetic 6) Fungi life forms include parasitic, pathogenic and saprophytic forms
FUNGAL FORMS
Fungi are of two forms based on classification by HYPHAE structure. Cross walls which forms partitions in the mycelium (SEPTAE) may be present or absent. COENOCYTIC mycelia (Ascomycota) have such partitions, which may be or may not be perforated. NON-COENOCYTIC mycelia (Basidio and Zygo mycota) have no such partitions.
CLASSIFICATION OF FUNGI
Fungi are classified according to their reproductive structures into the following classes:
1) ZYGOMYCOTA: sexual by fusion of plus and minus strains (hyphae) to formation of zygote. Asexual by non motile spores. E.g Rhizopus stolonifer (bread molds).
2) ASCOMYCOTA: sexual reproduction by fusion of plus minus strains. Zygotes formed from resulting massive hyphae, in SAC-LIKE structures called ASCUS, which bear ascopores and are enclosed in groups by the PERITHECIUM. Important ascomycetes fungi are yeasts and penicillum.
3) BASIDIOMYCOTA: Zygotes produced within special reproductive structures called BASIDIA. Asexual by means of basidiospores. E.g mushrooms 4) MYXOMYCOTA: Cellular slime molds. Curious life cycle. Free living amoebas aggregate into a slimy multicellulate slug. Motile organism. Sporangium develop as an offshoot on the slug.
5)OOMYCOTA: Asexual by non motile conidia (spores) or motile flagellated zygospores. Sexual by conjugion I.e fusion of male and female (plus and minus strains). 6) DEUTEROMYCOTA: The FUNGI IMPERFECTI. They have not been observed to reproduce sexually. So are classed separately.
7) PHYCOMYCOTA: An obsolete name used to describe the joint division of lower fungi. Some are microscopic. They are motile. They include Acrasiomycota, Chytidiomycota, Myxomycota, and Oomycota. N.B groups 4, 5, 6 & 7 are not true fungi because they lack one or two of the general characteristics of true fungi.
HABITATS
Fungi are found in any habitat you can think of. From the ocean floor, to fresh water habitats, in animals and plants, on human skin, 80% are abundant in and associated with forests, with a large quantity of decaying organic matter. ECOLOGY AND ECONOMIC IMPORTANCE
Fungi obtain their food either by living off dead matter as saprobes or on live organisms as parasites. Saprobic fungi contribute to the sustainability of food chains and webs of typical terrestrial ecosystems. Parasitic fungi have an adapted foot called HAUSTORIA for absorbing nutrients from living cells of their hosts. Like bacteria, fungi are known to cause bio deterioration of synthetic materials. They are not effective monitors of environmental pollution, but fungi are known for binding soil particles together. Pathogenic and saprobic fungi reduce the nutritional value of foodstuffs. In pharmaceuticals, fungal extracts are used in drug production e.g cyclosporine "wonder drug". Yeasts are use in baking and in fermentation processes. Next lecture in this series:-
INTRODUCTION
Fungi belong to the kingdom "fungi" in taxonomy. Most fungi consist of mainly eukaryotic unicellular organisms. They are non photosynthetic, and majorly terrestrial, with a few aquatic (water molds). They are saprophytic, being primary decomposers in any ecosystem, and are equipped with a powerful resource of enzymes which break down complex organic molecules. The study of fungi is called MYCOLOGY.
REPRODUCTION
Generally fungi reproduce via vegetative, asexual or sexual means.
1) The most common form of vegetative means is FRAGMENTATION of the HYPHAE ( any of the long, threadlike filaments of fungi mycelium).
2) Asexual reproduction is by SPORE formation. Spores are produced by special bodies called SPORANGIA (or CONIDIA ) that bear conidiogenous ( spore producing ) cells. Sometimes sexual spores are produced and these act as gametes in sexual reproduction.
3) Sexual reproduction occurs often. A large number of fungi reproduce sexually by fusion of haploid sexual gametes to form a diploid zygote.
GENERAL CHARACTERISTICS
True fungi have the following characteristics;
1) Rigid cell walls made of chitin 2) Glycogen as the basic form of storage polysaccharide 3) Almost all fungi produce spores (CRYPTOGRAMS) 4) All fungi are NON MOTILE in their life cycle 5) All fungi are non photosynthetic 6) Fungi life forms include parasitic, pathogenic and saprophytic forms
FUNGAL FORMS
Fungi are of two forms based on classification by HYPHAE structure. Cross walls which forms partitions in the mycelium (SEPTAE) may be present or absent. COENOCYTIC mycelia (Ascomycota) have such partitions, which may be or may not be perforated. NON-COENOCYTIC mycelia (Basidio and Zygo mycota) have no such partitions.
CLASSIFICATION OF FUNGI
Fungi are classified according to their reproductive structures into the following classes:
1) ZYGOMYCOTA: sexual by fusion of plus and minus strains (hyphae) to formation of zygote. Asexual by non motile spores. E.g Rhizopus stolonifer (bread molds).
2) ASCOMYCOTA: sexual reproduction by fusion of plus minus strains. Zygotes formed from resulting massive hyphae, in SAC-LIKE structures called ASCUS, which bear ascopores and are enclosed in groups by the PERITHECIUM. Important ascomycetes fungi are yeasts and penicillum.
3) BASIDIOMYCOTA: Zygotes produced within special reproductive structures called BASIDIA. Asexual by means of basidiospores. E.g mushrooms 4) MYXOMYCOTA: Cellular slime molds. Curious life cycle. Free living amoebas aggregate into a slimy multicellulate slug. Motile organism. Sporangium develop as an offshoot on the slug.
5)OOMYCOTA: Asexual by non motile conidia (spores) or motile flagellated zygospores. Sexual by conjugion I.e fusion of male and female (plus and minus strains). 6) DEUTEROMYCOTA: The FUNGI IMPERFECTI. They have not been observed to reproduce sexually. So are classed separately.
7) PHYCOMYCOTA: An obsolete name used to describe the joint division of lower fungi. Some are microscopic. They are motile. They include Acrasiomycota, Chytidiomycota, Myxomycota, and Oomycota. N.B groups 4, 5, 6 & 7 are not true fungi because they lack one or two of the general characteristics of true fungi.
HABITATS
Fungi are found in any habitat you can think of. From the ocean floor, to fresh water habitats, in animals and plants, on human skin, 80% are abundant in and associated with forests, with a large quantity of decaying organic matter. ECOLOGY AND ECONOMIC IMPORTANCE
Fungi obtain their food either by living off dead matter as saprobes or on live organisms as parasites. Saprobic fungi contribute to the sustainability of food chains and webs of typical terrestrial ecosystems. Parasitic fungi have an adapted foot called HAUSTORIA for absorbing nutrients from living cells of their hosts. Like bacteria, fungi are known to cause bio deterioration of synthetic materials. They are not effective monitors of environmental pollution, but fungi are known for binding soil particles together. Pathogenic and saprobic fungi reduce the nutritional value of foodstuffs. In pharmaceuticals, fungal extracts are used in drug production e.g cyclosporine "wonder drug". Yeasts are use in baking and in fermentation processes. Next lecture in this series:-
BIO 102 DIVERSITY OF FUNGI
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Wednesday, August 17, 2016
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Wednesday, August 17, 2016
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