Protists and Fungi

Lesson 6.02

Why was the mushroom invited to the party?

Biology Bytes

SC.912.L.15.1 Evolution

• Practice Questions (Here)
• State EOC Resources (Here)
• Tutorial Video (Here

Darwin defined evolution as "descent with modification," the idea that species change over time, give rise to new species, and share a common ancestor. The mechanism that Darwin proposed for evolution is natural selection.

Evidence for Evolution

1. Fossil Record

2. Comparative Anatomy

3. Biogeography

4. Comparative embryology

5. Molecular Biology (DNA)

All living things on Earth share the same universal code in DNA and RNA molecules, which indicates that they share a common ancestor. The more nucleotide sequences two species' DNA molecules have in common, the more closely related they appear to be on the evolutionary timeline.

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Lesson 6.02

Protists and Fungi

Lets recap, how many Domains are there? What about Kingdoms?

3/13/2025

Kingdom Protista (Protists)

Classifying protists has been a difficult task for scientists.

Protists were traditionally subdivided into several groups based on their physical similarities to the "higher" kingdoms of Animals, Plants, and Fungi. For example, the unicellular, “animal-like” protozoa, the “plant-like” algae, and the “fungus-like” slime molds and water molds are all protists. The features that define these groups often overlap.

Newer classifications attempt to group protists based on their cell structure and their biochemistry.

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Kingdom Protista (Protists)

Protists are also classified based on some of the following traits:

• The presence or absence of certain organelles such as mitochondria and chloroplasts.
• The number of membranes that surround the chloroplast (two, three, or four).
• The types of chlorophylls and accessory pigments in the cell.
• The ability to move and the method of movement.
• The way they obtain their food (photosynthetic or heterotrophic)

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Animal-like protists use three common forms of locomotion: flagella, pseudopodia, and cilia. Each of these forms distinguishes animal-like protists from one another.

Kingdom Protista (Protists)

All protists have the following similarities:

• Simple structure
• Unicellular (or multicellular colonies)
• Eukaryotic
• Lack specialization within cells
• Most have mitochondria
• They can reproduce asexually or sexually
• Many are parasites
• All prefer aquatic or moist environments
• Some contain chloroplasts for photosynthesis

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3 Divisions; Animal Like “swallow their food”, Fungus like “absorb from environment”, and Plant like “are autotrophic” with sunlight.

Kingdom Protista (Protists)

Animal Like Protists: Animal-like protists, referred to as protozoa, share two characteristics with animals: they are mobile and heterotrophic.

Animal-like protists can consume food using endocytosis or pinocytosis. In both processes, the cell membrane folds inward to take in substances from the outside, but in pinocytosis, protists also use their cell membranes to form food vacuoles around their prey, which is usually a bacterium. The protists produce toxins that paralyze the bacteria. Once paralyzed, bacteria are brought into the protist’s cytoplasm for breakdown and consumption.

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Protists:

Algae, slime molds, and amoebas are types of protists. A protist is any eukaryotic organism that isn't a plant, animal, or fungi.

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Here are their traits:

• multicellular or single-celled
• eukaryotic
• may be autotrophic or heterotrophic
• belong to the Eukarya domain

Fungi:

What do mushrooms, mold, mildew, and yeast have in common? These are some common household things in the kitchen or even unwanted in the bathroom!

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Here are their traits:

• mostly multicellular; some single-celled
• eukaryotic
• heterotrophic (get nutrition through absorption of dead or decaying organisms)
• belong to the Eukarya domain

Kingdom Fungi

• All fungi are eukaryotic cells
• The cells of fungi:
• Possess non-cellulose cell walls (often made of the polysaccharide chitin)
• Fungi are saprotrophs:
• They obtain energy and carbon by digesting dead/decaying matter extracellularly or from being parasites on living organisms
• Fungi reproduce asexaully using spores that disperse onto the ground nearby. The spores may be released actively or passively. Yeast using budding as a form of asexaul reproduction.

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The oldest organism in the world is thought to be a fungus.

Kingdom Fungi

• Fungi have a simple body form:
• They can be unicellular (like the common baker’s yeast Saccharomyces cerevisiae)
• Some consist of long threads called hyphae that grow from the main fungus body (mycelium)
• Larger fungi possess fruiting bodies that release large numbers of spores

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Rhizoids are root like growths that absorb nutrients from soil. They do NOT contain vascular tissues like plants do. Their membranes are porous so water and nutrients can pass through.

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Stolons (or Hyphae) are connective outgrowth from

one fungus to another.

Why are they important?

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1. Recycling – They play a major role in recycling the dead and decayed matter.
2. Food – The mushrooms species which are cultured are edible and are used as food by humans.
3. Medicines – There are many fungi that are used to produce antibiotics and to control diseases in humans and animals. Penicillin antibiotic is derived from a common fungus called Penicillium.
4. Biocontrol Agents – Fungi are involved in exploiting insects, other small worms and help in controlling pests. Spores of fungi are used as a spray on crops.
5. Food spoilage – Fungi play a major role in recycling organic material and are also responsible for major spoilage and economic losses of stored food.

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EOC Practice

Organisms classified as fungi have unique characteristics. Which of the following characteristics is found only in organisms classified in the kingdom fungi?

A. single cells without a nucleus

B. multicellular with chloroplasts

C. multicellular filaments that absorb nutrients

D. colonies of single, photosynthetic cells that reproduce asexually

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EOC Practice

Organisms classified as fungi have unique characteristics. Which of the following characteristics is found only in organisms classified in the kingdom fungi?

A. single cells without a nucleus

B. multicellular with chloroplasts

C. multicellular filaments that absorb nutrients

D. colonies of single, photosynthetic cells that reproduce asexually

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These filaments, called hyphae extend into the fungi’s food source and absorb nutrients.

Fungi are not able to make their own food.

Complete Quiz 6.02