Fungi: Chapter 21

Characteristics of the common morel

• the most prized of all foods

• grows wild in woodlands throughout the United States.

• Its ridged cap is often camouflaged by dead leaves that collect in abandoned orchards or underneath old oaks or tulip poplars.

• Some morels grow alone, but others grow in groups.

• They appear suddenly, often overnight,

• live for only a few days.

• are fungi

Fungi

eukaryotic heterotrophs that have cell walls.

Fungi were once classified as ____________________________

Nonphotosynthetic plants. The way in which many fungi grow from the ground once led scientists to classify them as nonphotosynthetic plants.

chitin

a complex carbohydrate that is also found in the external skeletons of insects.

If fungi do not ingest their food, what do they do?

they digest food outside of their bodies and then absorb it.

Two ways fungi can absorb food

Many fungi feed by absorbing nutrients from decaying matter in the soil.

Others live as parasites, absorbing nutrients from the bodies of their hosts.

hyphae

tiny filaments that make up multicellular fungi

Each hypha is only ___ cell thick.

one

What can divide the hyphae into cells?

Cross walls can divide the hyphae into cells contained one or two nuclei.

In the cross walls, there are ______________________________________

tiny openings through which the cytoplasm and nuclei can move.

mycelium.

The bodies of multicellular fungi composed of many hyphae tangled together into a thick mass

Why is the mycelium well suited to absorb food?

it permits a large surface area to come in contact with the food source through which it grows.

fruiting body

a reproductive structure that develops from a mycelium that grows below the surface of the ground.

Clusters of mushrooms are often part of

the same mycelium, which means that they are part of a single organism.

What causes fairy rings?

As time goes by, soil nutrients near the center of the mycelium become depleted. As a result, new mushrooms sprout only at the edges of the mycelium,

Over many years, fairy rings can become enormous — from __ to __ meters in diameter.

10, 30

When does asexual reproduction occur in fungi?

when cells or hyphae break off from a fungus and begin to grow on their own.

Some fungi also produce spores, which can scatter and grow into new organisms.

Sporangia

A structure at the tip of a sporangiophore wherein spores are produced

sporangiophores

specialized hyphae

Fungal mating types

"+" (plus) and "-" (minus).

Why fungal gametes aren't called male and female

Because they are about the same size.

Gametangium

A structure formed by hyphae that produces gametes.

Zygote formation in fungi

Formed when haploid nuclei from joined gametangia fuse.

Role of meiosis in fungal reproduction

Takes place after the zygote forms, producing haploid nuclei.

Diploid cells in the fungal life cycle

In most fungi, the zygote is the only diploid cell.

Distribution of fungal spores

Found in almost every environment.

Wind-dispersed fungal spores

Dry and almost weightless, scattering easily in the wind.

Spore germination requirements

Must land in a favorable environment with proper temperature, moisture, and food.

Probability of a spore producing a mature organism

Can be less than one in a billion.

Stinkhorn spore dispersal method

Smells like rotting meat to attract flies, which pass spores unharmed.

Asexual reproduction in fungi

Often involves spore formation, such as via raindrops hitting puffballs.