Chapter 9 Protists and Fungi

Kingdom Protista A protist is a single or many-celled organism that lives in moist or wet surroundings. All protists have a nucleus and are therefore eukaryotic. Protists are:Plantlike Animal-like Funguslike

Plantlike Protists Plantlike protists are known as algae. Some species of algae are one-celled and others are many-celled. All algae can make their own food because they contain the pigment chlorophyll in their chloroplasts. Species of algae are grouped into six main phyla mainly according to their pigments and the form in which they store food.

Six Main Phyla of Algae Euglenas Diatoms Dinoflagellates Green Algae Red Algae Brown Algae

Euglenas They have characteristics of both plants and animals. These one celled algae have chloroplasts and produce carbohydrate as food. An animal-like characteristic is the adaptation called an eyespot that responds to light.

Diatoms Diatoms are photosynthetic, one-celled algae that store food in the form of oil. They have golden-brown pigment that masks the green chlorophyll. Diatoms reproduce in extremely large numbers. When they die, their small shells sink to the floor of the body of water and collect in deep layers. They are mined with power shovels and used in insulation, filters, road paint, and toothpaste.

Pictures of Diatoms

Diatoms

Algae to Biodiesel

Algae to Biofuel

Dinoflagellates They are one-celled and have red pigments. Dinoflagellate means “spinning flagellates.” One of the flagella moves the cell, and the other circles the cell, causing it to spin with a motion similar to a top. Almost all live in salt water. They are an important food source for many saltwater organisms.

Pictures of Dinoflagellates

Green Algae There are several thousand species of green algae. The presence of chlorophyll tells you that they undergo photosynthesis and produce food in the form of starch. They can be one-celled or many-celled. Most live in water, others can live in trunks of trees and even on other organisms.

Pictures of Green Algae

Red Algae If you’ve ever eaten pudding or used toothpaste, you have used something made of red algae. A carbohydrate called carrageenan is used to give these things their smooth texture. Most are many-celled. Some species of red algae can live up to 175m deep in the ocean. That’s 574 feet – almost 2 football fields.

Pictures of Red Algae

Brown Algae Members of this phylum are many-celled and vary greatly in size. Kelp is an important food source for many fish and invertebrates. Small fish and other animals live in the dense mat of stalks and their leaflike blades. The thick texture of foods such as ice cream and marshmallows is produced by a carbohydrate called algin found in these algae

Pictures of Brown Algae

Animal-Like Protists One-celled animal-like protists are known as protozoa. They live in water, soil, and both living and dead organisms. Many types are parasites. Protozoans contain special vacuoles for digesting food and getting rid of excess water.

Four Kinds of Protozoan Based on their method of movement Sarcodines Flagellates Ciliates Sporozoans

Sarcodines Sarcodines move about and feed using temporary extensions of their cytoplasm called pseudopods. Pseudopod means “false foot” Sarcodines are found in freshwater and saltwater environments, and certain types are found in animals as parasites.

Examples of Sarcodines

Flagellates Protozoans that move using flagella are called flagellates. Trypanosoma is a flagellate that causes African sleeping sickness in humans and other animals. Another flagellate lives in the digestive system of termites. They produce enzymes that digest the wood the termites eat. Tsetse Fly

Examples of Flagellates

Termites

The Formosan subterranean termite is often nicknamed the super-termite because of its destructive habits. This is because of the large size of its colonies, and the termites' ability to consume wood at a rapid rate. A single colony may contain several million individuals (compared with several hundred thousand termites for other subterranean termite species) that forage up to 300 feet (100 m) in soil. A mature [1] Formosan colony can consume as much as 13 ounces of wood a day (ca. 400 g) and severely damage a structure in as little as three months.colonieswood[1]ounces

Ciliates Members of this phylum move by using cilia. Cilia are short, threadlike structures that extend from the cell membrane. A typical ciliate is Paramecium. Paramecium usually feed on bacteria swept into the oral groove. Once the food is inside the cell, a food vacuole forms and the food is digested.

Examples of Ciliates

Sporozoans They are parasistic and have no way of moving on their own. All are parasites that live and feed on the blood of humans and other animals. Malaria is a sporozoan that is spread when an infected mosquito bites a human.

Examples of Sporozoans

Video Segment of Protists (6:59)

Funguslike Protists They have features of both protists and fungi. Slime molds and water molds are funguslike protists. They obtain energy by decomposing organic materials. They form a delicate, weblike structure on the surface of their food supply.

Slime Molds Many have beautiful colors. During part of their life cycle, the cells of slime molds move by means of pseudopods and behave like amoebas. They reproduce with spores the way fungi do. Most live on decaying logs or dead leaves in moist, cool, shady woods.

Examples of Slime Molds

Water Molds and Downy Mildew Most live in water or moist places. Most appear as fuzzy, white growths on decaying matter. They grow as a mass of threads over a plant or animal, digest it, and then absorb the organism’s nutrients They produce reproductive cells with flagella at some point in their reproductive cycles.

Water Molds and Downy Mildew Some water molds are parasites of plants while others feed on dead organisms, such as fish. A water mold caused the Irish potato famine in the 1840’s. It caused potatoes to rot in the field leaving many people with no food. Nearly one million people died. This water mold continues to be a problem for potato growers. Downy mildew causes serious disease in many plants

Potato Field

Examples of Water Molds (Top) and Downy Mildew (Bottom)

Red Tides For reasons that are not completely understood, every once in a while the population of certain species of dinoflagellates increases rapidly. The population of algae may be so dense that red pigments in the algae cause the water to look red. Each species of dinoflagellates releases a different kind of toxin. Fish and shellfish may eat the dinoflagellates that are a part of the plankton. People who eat the fish or shellfish may become ill or sometimes die.

Underlying Causes of Red Tide Red tides often occur where water becomes heated or where freshwater runoff creates a layer of warm surface water above a coldwater layer that is rich in nutrients. Sometimes the red tides spread for hundreds of miles along a coastline.

Red Tide Video Segment (3:47)

Picture of Red Tide

Kingdom Fungi Fungi do not make their own food or have the specialized tissues and organs of plants. Most species are many-celled. The body of a fungus is usually a mass of many-celled, threadlike tubes called hyphae. Most feed on dead or decaying tissues. A fungus secretes enzymes to digest food outside of itself. Then the fungus cells absorb the digested food.

Kingdom Fungi Fungi that cause athlete’s foot and ringworm are parasites. They obtain their food directly from living things. Fungi grow best in warm, humid areas, such as tropical forests or the spaces between your toes. Spores are reproductive cells that form new organisms without fertilization. The structures that produce spores are used to classify fungi into one of four divisions.

Zygote Fungi Fuzzy black mold you might find growing on old bread or a piece of fruit. They produce spores in round spore cases called sporangia. When a sporangia opens, hundreds of spores are released into the air.

Sac Fungi Yeasts, molds, morels, and truffles are all examples of sac fungi. Spores of these fungi are produced in a little saclike structure called an ascus. Many sac fungi destroy plant crops: Dutch elm disease, apple scab, and ergot disease of rye.

Pictures of Sac Fungi Bakers Yeast Morels Truffles

Diseases caused by Sac Fungi Dutch Elm Disease Apple Scab

Disease caused by Sac Fungi Ergot Disease of Rye

Club Fungi The spores of these fungi are produced in a club-shaped structure called a basidium. Many of the club fungi are economically important. Cultivated mushrooms are an important food crop, but you should never eat a wild mushroom because many are poisonous.

Examples of Club Fungi

Mushrooms Grown in Pennsylvania Enoki Button Cap CriminiShitake

Mushrooms Grown in Pennsylvania Bluefoot (Blewit) Royal Trumpets Honey (Nameko) Hen of the Woods Beech (White or Brown) Pom-Poms

Mushrooms Grown in Pennsylvania Pioppini Abalone Nebrodini Chanterelle Porcini Lobster

Imperfect Fungi They are a species of fungi in which a sexual stage has never been observed. When a sexual stage of one of these fungi is observed, the species is immediately classified as one of the other three phyla. Penicillium is one example from this group. Penicillin, an antibiotic, is an important product of this fungus. Other examples are species that cause ringworm and athlete’s foot.

Examples of Imperfect Fungi

Ringworm Athlete’s Foot

Lichens A lichen is an organism that is made of a fungus and either a green alga or a cyanobacteria. Lichens are an important food source for many animals. Lichens are important in the erosion process because they are able to grow on bare rock. Lichens release acids which break down rock. Soil is eventually formed. Lichen are pioneer species.

Examples of Lichens

Lichens on a Roof

Mount St. Helens Before Eruption Mount St. Helens After Eruption

Pioneer Species

Video Segment of Fungi (14:28)