Table of Contents – pages iii

Table of Contents – pages iii Unit 1:What is Biology? Unit 2:Ecology Unit 3:The Life of a Cell Unit 4:Genetics Unit 5:Change Through Time Unit 6:Viruses, Bacteria, Protists, and Fungi Unit 7:Plants Unit 8:Invertebrates Unit 9:Vertebrates Unit 10:The Human Body

Table of Contents – pages vii-xiii Unit 1: What is Biology? Chapter 1:Biology: The Study of Life Unit 2: Ecology Chapter 2:Principles of Ecology Chapter 3:Communities and Biomes Chapter 4:Population Biology Chapter 5:Biological Diversity and Conservation Unit 3:The Life of a Cell Chapter 6:The Chemistry of Life Chapter 7:A View of the Cell Chapter 8:Cellular Transport and the Cell Cycle Chapter 9:Energy in a Cell

Unit 4: Genetics Chapter 10:Mendel and Meiosis Chapter 11:DNA and Genes Chapter 12:Patterns of Heredity and Human Genetics Chapter 13:Genetic Technology Unit 5: Change Through Time Chapter 14:The History of Life Chapter 15:The Theory of Evolution Chapter 16:Primate Evolution Chapter 17:Organizing Life’s Diversity Table of Contents – pages vii-xiii

Unit 6: Viruses, Bacteria, Protists, and Fungi Chapter 18:Viruses and Bacteria Chapter 19:Protists Chapter 20:Fungi Unit 7: Plants Chapter 21:What Is a Plant? Chapter 22:The Diversity of Plants Chapter 23:Plant Structure and Function Chapter 24:Reproduction in Plants Table of Contents – pages vii-xiii

Table of Contents – pages vii-xiii Unit 8: Invertebrates Chapter 25:What Is an Animal? Chapter 26:Sponges, Cnidarians, Flatworms, and Roundworms Chapter 27:Mollusks and Segmented Worms Chapter 28:Arthropods Chapter 29:Echinoderms and Invertebrate Chordates

Table of Contents – pages vii-xiii Unit 9: Vertebrates Chapter 30:Fishes and Amphibians Chapter 31:Reptiles and Birds Chapter 32:Mammals Chapter 33:Animal Behavior Unit 10: The Human Body Chapter 34:Protection, Support, and Locomotion Chapter 35:The Digestive and Endocrine Systems Chapter 36:The Nervous System Chapter 37:Respiration, Circulation, and Excretion Chapter 38:Reproduction and Development Chapter 39:Immunity from Disease

Unit Overview – pages 472-473 Viruses, Bacteria, Protists, and Fungi Viruses and Bacteria Protists Fungi

Chapter Contents – page ix Chapter 20Fungi 20.1:What is a fungus? 20.1:Section Check 20.2:The Diversity of Fungi 20.2:Section Check Chapter 20Summary Chapter 20Assessment

Chapter Intro-page 528 What You’ll Learn You will identify the characteristics of the fungi kingdom. You will differentiate among the phyla of fungi.

20.1 Section Objectives – page 529 Section Objectives: • Identify the basic characteristics of the fungi kingdom. • Explain the role of fungi as decomposers and how this role affects the flow of both energy and nutrients through food chains.

Section 20.1 Summary – pages 529-534 The Characteristics of Fungi • Fungi are everywhere—in the air and water, on damp basement walls, in gardens, on foods, and sometimes even between people’s toes.

Section 20.1 Summary – pages 529-534 The Characteristics of Fungi • Some fungi are large, bright, and colorful, whereas others are easily overlooked. • Many species grow best in moist environments at warm temperatures between 20°C and 30°C.

Section 20.1 Summary – pages 529-534 The Characteristics of Fungi • Fungi used to be classified in the plant kingdom because, like plants, many fungi grow anchored in soil and have cell walls. • However, as biologists learned more about fungi, they realized that fungi belong in their own kingdom.

Section 20.1 Summary – pages 529-534 The structure of fungi • Although there are a few unicellular types of fungi, such as yeasts, most fungi are multicellular. • The basic structural units of multicellular fungi are their threadlike filaments called hyphae (HI fee) (singular, hypha), which develop from fungal spores.

Section 20.1 Summary – pages 529-534 The structure of fungi Germinating Spore Mycelium Spore Food Source

Section 20.1 Summary – pages 529-534 The structure of fungi • There are different types of hyphae in a mycelium. Some anchor the fungus, some invade the food source, and others form fungal reproductive structures.

Section 20.1 Summary – pages 529-534 The structure of fungi • Unlike plants, which have cell walls made of cellulose, the cell walls of most fungi contain a complex carbohydrate called chitin (KI tun). • Chitin gives the fungal cell walls both strength and flexibility.

Section 20.1 Summary – pages 529-534 The structure of fungi Click image to view movie.

Section 20.1 Summary – pages 529-534 Inside hyphae • In many types of fungi, cross walls called septa (singular, septum) divide hyphae into individual cells that contain one or more nuclei. • Septa are usually porous, allowing cytoplasm and organelles to flow freely and nutrients to move rapidly from one part of a fungus to another.

Section 20.1 Summary – pages 529-534 Inside hyphae Septum Nuclei Cell Wall Cytoplasm

Section 20.1 Summary – pages 529-534 Inside hyphae • Some fungi consist of hyphae with no septa. Nuclei Cytoplasm Cell Wall

Section 20.1 Summary – pages 529-534 Inside hyphae • Under a microscope, you see hundreds of nuclei streaming along in a continuous flow of cytoplasm. • As in hyphae with septa, the flow of cytoplasm quickly and efficiently disperses nutrients and other materials throughout the fungus.

Section 20.1 Summary – pages 529-534 Adaptations in Fungi • Fungi can be harmful. • Some cause food to spoil. Some cause diseases, and some are poisonous. However, they play an important and beneficial role. • In a world without fungi, huge amounts of wastes, dead organisms, and debris, which consist of complex organic substances, would litter Earth.

Section 20.1 Summary – pages 529-534 Adaptations in Fungi • Many fungi, along with some bacteria and protists, are decomposers. • They break down complex organic substances into raw materials that other living organisms need.

Section 20.1 Summary – pages 529-534 How fungi obtain food • Fungi are heterotrophs, and they use a process called extracellular digestion to obtain nutrients. • In this process, food is digested outside a fungus’s cells, and the digested products are then absorbed.

Section 20.1 Summary – pages 529-534 How fungi obtain food Chemicals released by hyphae digest dead materials. Hyphae absorb the digested food.

Section 20.1 Summary – pages 529-534 How fungi obtain food • For example, as some hyphae grow into the cells of an orange, they release digestive enzymes that break down the large organic molecules of the orange into smaller molecules.

Section 20.1 Summary – pages 529-534 How fungi obtain food • These small molecules diffuse into the fungal hyphae and move in the free-flowing cytoplasm to where they are needed for growth, repair, and reproduction.

Section 20.1 Summary – pages 529-534 Different feeding relationships • A fungus may be a saprophyte, a mutualist, or a parasite depending on its food source. • Saprophytes are decomposers and feed on waste or dead organic material. • Mutualists live in a symbiotic relationship with another organism, such as an alga.

Section 20.1 Summary – pages 529-534 Different feeding relationships • Parasites absorb nutrients from the living cells of their hosts.

Section 20.1 Summary – pages 529-534 Different feeding relationships Fungal hypha Haustorium Host cell

Section 20.1 Summary – pages 529-534 Reproduction in Fungi • Depending on the species and on environmental conditions, a fungus may reproduce asexually or sexually. • Fungi reproduce sexually by fragmentation, budding, or producing spores.

Section 20.1 Summary – pages 529-534 Fragmentation and budding • In fragmentation, pieces of hyphae that are broken off of a mycelium grow into new mycelia.

Section 20.1 Summary – pages 529-534 Fragmentation and budding • The unicellular fungi called yeasts often reproduce by a process called budding—a form of asexual reproduction in which mitosis occurs and a new individual pinches off from the parent, matures, and eventually separates from the parent. Yeast budding

Section 20.1 Summary – pages 529-534 Reproducing by spores • Most fungi produce spores. • When a fungal spore is transported to a place with favorable growing conditions, a threadlike hypha emerges and begins to grow, eventually forming a new mycelium. • The mycelium becomes established in the food source.

Section 20.1 Summary – pages 529-534 Reproducing by spores Spores Bread Mold Sporangium Hyphae

Section 20.1 Summary – pages 529-534 Reproducing by spores • Many fungi can produce two types of spores—one type by mitosis and the other by meiosis—at different times during their life cycles. • One important criterion for classifying fungi into divisions is their patterns of reproduction, especially sexual reproduction, during the life cycle.

Section 20.1 Summary – pages 529-534 The adaptive advantages of spores • Many adaptive advantages of fungi involve spores and their production.

Section 20.1 Summary – pages 529-534 The adaptive advantages of spores • First, the sporangia protect spores and, in some cases, prevent them from drying out until they are ready to be released. • Second, most fungi produce a large number of spores at one time.

Section 20.1 Summary – pages 529-534 The adaptive advantages of spores • Producing so many spores increases the germination rate and improves the species survival chances. • Finally, fungal spores are small and lightweight and can be dispersed by wind, water, and animals such as birds and insects.

Section 1 Check Question 1 Hyphae develop from _______. (TX Obj 2; 8C) A. spores B. chitin C. cellulose D. rhizoids

Section 1 Check The answer is A, spores. Spores Bread Mold Sporangium Hyphae

Section 1 Check Question 2 A mycelium is composed of _______. (TX Obj 2; 8C) A. spores B. hyphae C. sporangia D. conidiophores The answer is B, hyphae.

Section 1 Check Question 3 What are three different functions that hyphae can perform in a mycelium? (TX Obj 2; 8C) Answer Some hyphae anchor the fungus, some invade the food source, and others form fungal reproductive structures.

Section 1 Check Question 4 Explain how a fungus performs extracellular digestion. (TX Obj 2; 8C) Answer Hyphae grow into the cells of the food source, releasing digestive enzymes that break down large organic molecules into smaller molecules. These molecules move in the free-flowing cytoplasm to where they are needed for growth, repair, and reproduction.

Section 1 Check Question 5 Which type of fungi lives in a symbiotic relationship with another organism? (TX Obj 2; 8C) A. parasites B. saprophytes C. mutualists D. decomposers The answer is C, mutualists.

20.2 Section Objectives – page 535 Section Objectives • Identify the four major phyla of fungi. • Distinguish among the ways spores are produced in zygomycotes, ascomycotes, and basidiomycotes. • Summarize the ecological roles of lichens and mycorrhizae.

Section 20.2 Summary – pages 535-543 Zygomycotes • You have probably seen Rhizopus stolonifer, a common bread mold.

Section 20.2 Summary – pages 535-543 Zygomycotes • Rhizopus is probably the most familiar member of the phylum Zygomycota (zy goh mi KOH tuh). • Many other members of about 1500 species of zygomycotes are also decomposers.

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