Fungi

Fungi

Middle School

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Learning Objectives

• Describe the main characteristics of organisms in the Fungi kingdom.

• Explain the key differences between fungi and plants.

• Identify the methods of asexual and sexual reproduction in fungi.

• Explain the different roles fungi play in ecosystems, including symbiotic relationships.

Key Vocabulary

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Fungi

A kingdom in the Eukarya domain that includes organisms like molds, mushrooms, and yeasts.

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Chitin

This is a special sugar that builds the strong cell walls of all fungi.

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Hyphae

These are the tiny, thread-like tubes that make up the body of a multicellular fungus.

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Mycelium

This is the main body of a fungus, which is made of a mass of hyphae.

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Mycorrhiza

A partnership where a fungus and a plant live together and help each other survive.

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Lichen

A partnership between a fungus and an organism that can make its own food using sunlight.

Characteristics of Fungi

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Single-Celled Fungi

• Fungi are eukaryotic organisms that exist in their own unique kingdom.

• Some fungi, like yeast, are made of just a single cell.

• These types of fungi are microscopic and not visible to you.

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Multicellular Fungi

• Many fungi are multicellular and made of many cells working together.

• Molds are a common example of multicellular fungi found on food.

• The cell walls of fungi are made of a material called chitin.

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Mushroom Structure

• A mushroom’s body is a network of threads called a mycelium.

• These individual threads making up the mycelium are called the hyphae.

• Mushrooms belong to the phylum Basidiomycota, a major fungi group.

Multiple Choice

What is the main body of a multicellular fungus, composed of a network of hyphae, called?

• Chitin

• Mycelium

• Hypha

• Zygospore

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Fungi vs. Plants

Fungi

• Fungi are heterotrophs, so they cannot make their own food through photosynthesis.

• Their cell walls are made of a tough and protective material called chitin.

• Most fungi lack complex transport structures like the xylem and phloem found in plants.

Plants

• Plants are autotrophs, meaning they produce their own food from sunlight.

• In contrast, the cell walls of all plants are made of cellulose.

• Plants use xylem and phloem to transport water, minerals, and food throughout their bodies.

Multiple Choice

A major difference between fungi and plants is that fungi have cell walls made of what tough carbohydrate?

• Mycelium

• Glucose

• Chitin

• Cellulose

How Fungi Reproduce

• Most fungi reproduce asexually by releasing spores.

• Some single-celled yeasts reproduce by budding.

• Sexual reproduction occurs when two different hyphae fuse.

Multiple Choice

Which of the following is a form of sexual reproduction in fungi that increases genetic variation?

• Budding

• Fission

• Producing spores by mitosis

• Process of palasmogamy

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Fungi's Role in the World

• Fungi act as decomposers, recycling nutrients from dead material back into the soil.

• We use fungi as food like mushrooms and in medicine to make penicillin.

• They form helpful relationships like mycorrhiza with plants and lichens with algae.

• Some are parasites, causing diseases like athlete's foot and harming farm crops.

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Multiple Choice

A lichen is a composite organism formed from a symbiotic relationship between a fungus and what other organism?

• Bacteria

• Algae or cyanobacteria

• Protozoa

• Viruses

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Common Misconceptions About Fungi

Misconception	Correction
Fungi are a type of plant.	Fungi are heterotrophs in their own kingdom with cell walls made of chitin.
All fungi are mushrooms.	The Fungi kingdom also includes molds and single-celled yeasts.
All fungi are harmful.	Many are decomposers. We use them for food and life-saving antibiotics.

Multiple Choice

Why are fungi, which often grow in soil like plants, classified in their own separate kingdom?

• Because they can be both single-celled and multi-celled.

• Because they have similar structures to plants like roots.

• Because they are heterotrophs and have cell walls of chitin.

• Because they reproduce using spores and live in the soil.

Multiple Choice

A fungus is discovered that reproduces by budding. What can you conclude about this fungus?

• It is a multicellular mushroom reproducing sexually.

• It is forming a parasitic relationship with a plant.

• It is a single-celled yeast reproducing asexually.

• It is creating a diploid zygospore for genetic diversity.

Multiple Choice

A farmer notices that her crops grow poorly. A scientist suggests introducing a specific fungus to the soil, after which the crops' health improves dramatically. What is the most likely explanation for this?

• The fungus formed a mycorrhizal relationship, helping the plants absorb nutrients.

• The fungus started producing penicillin, which acted as a fertilizer.

• The fungus started photosynthesizing, providing extra food for the plants.

• The fungus became a parasite, killing harmful insects in the soil.

Multiple Choice

Imagine a new chemical is developed that destroys chitin but is harmless to cellulose. What would be the most significant impact on an ecosystem?

• Insects with exoskeletons would be unaffected, but fungi would thrive.

• Fungi would die, halting decomposition and affecting nutrient cycles.

• Both plants and fungi would be eliminated from the ecosystem.

• Plants would die, because their cell walls would dissolve.

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Summary

• Fungi are eukaryotic heterotrophs with cell walls made of chitin.

• The body of a fungus is a mycelium, made of filaments called hyphae.

• Fungi reproduce both asexually for rapid spread and sexually for genetic diversity.

• They are vital as decomposers and symbionts, and used for food and medicine.

Poll

On a scale of 1-4, how confident are you about the concepts covered in today's review?

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