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THE KINGDOM FUNGI

OBJECTIVES 21.1

Identify the defining characteristics of fungi.

Describe the main structures of a fungus.

Explain how fungi reproduce.

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The common _____ grows wild in the woodlands throughout the US. It has a rigid cap that is often camouflaged by dead leaves in abandoned orchards.

What are fungi?

They are ________heterotrophs that cell walls.

The cell walls of fungi are made of ______ (a derivative of glucose).

Chitin is also found in the external skeletons of _____.

3Zygomycosis fungus

entomopathogenic fungus Zombie fungus

Spider

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Fungi are ________.

Fungi do not _____ their food. Instead they digest food outside of their bodies and then absorb it.

Many fungi obtain nutrients by absorbing them from decaying matter, while others live as ______.

Parasitic fungi absorb their nutrients from the ______ of their host.

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Cell wall

Cross wall

Nuclei

Cytoplasm

Hypae without cross walls

In the ____walls there are tiny openings that allow ______ and nuclei to move

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Fruiting body

The bodies of multicellular fungi are composed of many hypae tangled together into a thick mass called a _______.

The mycelium ______ food.

A fruiting body is a _________ structure

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Some mycelia can live for many years. As time goes by, soil nutrients near the center of mycelium become depleted. As a result, new _______ sprout only at the edges, producing a ring

Fairy ring

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Most fungi produce both sexually and ________.

In some fungi, spores are produced in structures called _____. They are found at the tips of special hyphae called ___________.

Asexual reproduction

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Sexual reproduction in fungi usually involves two different mating _____.

Because the gametes are about the same size they are called + (___) and – (____).

When opposing mating types meet, they start the processing of sexual reproduction by ______.

After a period of growth and development, these nuclei form a ______ zygote.

Most fungi, then enters _____, completing the sexual phase of its life cycle by producing haploid spores

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Devil snuff Stinkhorn

Fungi _____ are spread in many ways.

The puff ball disperses spores when stepped on or by rain.

______ smell like rotting meat and attracts flies.

The flies then eat the sticky substance on the stinkhorn and passes the spores out through its ________ system.

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CLASSIFICATION OF FUNGI

OBJECTIVE: 21.2

Identify the characteristics of the four main groups of fungi.

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The kingdom Fungi has over 100,000 species.

Fungi are classified according to their structure and method of reproduction.

The four main groups of fungi are the common mold (Zygomycota), the sac fungi (Ascomycota), the club fungi (Basidiomycota), and the imperfect fungi (Deuteromycota).

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Common mold

Zygomycetes have life cycles that include a zygospore (a resting spore that contains zygotes formed during the sexual phase of the mold’s life).

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Black bread mold

BBM has two types of hyphae.

Rhizoids are rootlike hyphae that penetrate the surface fo the bread.

Stolons are the stemlike hyphae that run along the surface of the bread.

BBM sexual phase starts when hyphae from different mating types fuse to produce gamete-forming structures known as gametangia.

Mating gametes may fuse and remain dormant for months until conditions are favorable to undergo meiosis.

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The Ascomycota is named for the ascus, a reproductive structure that contains spores.

Ascomycota is the largest phylum of the kingdom Fungi.

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The life cycle usually includes sexual and asexual reproduction.

In asexual reproduction, tiny spores called conidia are formed at the tips of specialized hyphae called conidiophores.

Sexual reproduction occurs when the haploid hyphae of two different mating types (+ and - ) grow close together.

The N + N hyphae then produces a fruiting body in which sexual reproduction continues.

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The ascus forms within the fruiting body.

Within the ascus, two nuclei of different mating types fuse to form a diploid zygote.

In most ascomycetes, meiosis is followed by a cycle of mitosis,so that eight cells known as ascospores are produced.

18Budding yeast cells

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Club fungi

The phylum Basidiomycota gets its name from a specialized reproductive structure that resembles a club.

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When the right combination of moisture and nutrients occurs, spore-producing fruiting bodies push above the ground.

When the cap opens, it exposes hundreds of tiny gills on its underside.

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Each gill is lined with basidia.

The two nuclei in each basidium fuse to form a 2N zygote, which then undergoes meiosis, forming a cluster of N basidiospores.

The basidiospores form at the of of each basidium and , within a few hours, are ready to be scattered.

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Deuteromycota (imperfect fungi) are fungi tht cannot be placed in other phyla because a sexual phase has never been observed in their life cycle.

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One of the best known imperfect fungi is penicillium.

Penicillium is a mold that frequently grows on fruit and is the source of the antibiotic penicillin.

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ECOLOGY OF FUNGI

OBJECTIVES 21.3

Explain what the ecological role of fungi is.

Describe problems that parasitic fungi cause.

Describe the kinds of mutualistic relationships that fungi form with other organisms.

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All fungi are heterotrophs, they cannot manufacture their own energy.

They rely on other organisms for their food.

Fungi cannot move to capture food.

Their mycelia can grow very fast into the tissue and cells of plants and other organisms.

Some fungi are saprobes, organisms that obtain food from decaying organic matter.

Others are parasites, which harm other organisms while living directly on or within them.

Still other fungi are symbionts that live in close and mutually benefical association with other species.

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Fungi play an essential role in maintaining equilibrium in nearly every ecosystem, where they recycle nutrients by breaking down the bodies and wastes of other organisms.

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Parasitic fungi cause serious plant and animal diseases.

A few cause diseases in humans.

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Mildew Rust

Fungal diseases such as corn smut, mildew, and wheat rust are responsible for the loss of about 15% of corps grown in tropical areas.

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Some fungi (lichens) form symbiotic relationships in which bother partners benefit.

Lichen and mycorrhizae are essential to many ecosystems.

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Mycorrhizae is essential for the growth of many plants.

The seeds of some plants cannot geminate without mycorrhizae.