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Chapter 26 Fungi

Table of Contents

Section 1 Overview of Fungi Section 2 Classification of Fungi Section 3 Fungi and Humans

Section 1 Overview of Fungi

Chapter 26

Objectives

• (^) List the characteristics of fungi.
• (^) Describe how fungi obtain nutrients.
• (^) Distinguish between hyphae and a mycelium.
• (^) Compare the ways fungi reproduce.
• (^) Describe one hypothesis about the origin of fungi.

Section 1 Overview of Fungi

Chapter 26

Characteristics, continued

Obtaining Nutrients

• Fungi are among the most important decomposers of organic matter.
• Fungi obtain nutrients by secreting enzymes and absorbing simple organic molecules from their environment.

Section 1 Overview of Fungi

Chapter 26

Characteristics, continued

Structure of Fungi

• Fungi are made up of short filaments called hyphae. - Mats of hyphae are called mycelium. - Some species have partitions called septa in their hyphae, making individual cells.
• Fungal cell walls contain chitin rather than cellulose, which is found in plant cell walls.

Chapter 26

Hyphae in Fungi

Section 1 Overview of Fungi

Chapter 26

Click below to watch the Visual Concept.

Visual Concept

Body Structure of Fungi

Section 1 Overview of Fungi

Section 1 Overview of Fungi

Chapter 26

Reproduction, continued

Asexual Reproduction

• Asexually, fungi produce thousands of genetically identical haploid spores, usually on modified cells of the hyphae.
• When these spores are placed in favorable environmental conditions, they germinate and grow new hyphae, each of which can form a mycelium and produce thousands of new asexual spores.

Section 1 Overview of Fungi

Chapter 26

Reproduction, continued

Sexual Reproduction

• Fungi occur in mating types that are sometimes called minus and plus.
• When two different mating types of the same species encounter one another, the hyphae of one mating type fuse with the hyphae of the opposite mating type.
• These fused hyphae give rise to a specialized structure, which produces and scatters genetically diverse spores.

Section 1 Overview of Fungi

Chapter 26

Evolution

• (^) Fungi evolved about 460 million years ago.
• (^) Fungi probably evolved from endosymbiotic prokaryotes and then adapted to various terrestrial environments.

Section 2 Classification of Fungi

Chapter 26

Objectives

• (^) List characteristics that distinguish three phyla of fungi.
• (^) Compare the life cycles of zygomycetes, basidiomycetes, and ascomycetes.
• (^) Distinguish between mycorrhizae and lichens.
• (^) Explain the importance of mycorrhizae and lichens to the environment.

Section 2 Classification of Fungi

Chapter 26

Phylum Zygomycota

• (^) The phylum Zygomycota is coenocytic (their hyphae lack septa).
• (^) Asexual sporangiospores form within sacs called sporangia.
• (^) Sexual reproduction results in zygospores.

Chapter 26

Life Cycle of Zygomycetes

Section 2 Classification of Fungi

Chapter 26

Click below to watch the Visual Concept.

Visual Concept

Sexual Reproduction in Zygomycetes

Section 2 Classification of Fungi

Section 2 Classification of Fungi

Chapter 26

Phylum Basidiomycota

• (^) The phylum Basidiomycota includes mushrooms.
• (^) Mushrooms are spore-bearing, aboveground sexual reproductive structures called basidiocarps.
• (^) Basidiocarps produce small, clublike reproductive structures called basidia, on which basidiospores form.