PROTISTS AND FUNGI Chapter 8

PROTISTS Section 1

PROTISTS Eukaryotic One- or many celled organisms which live in a moist or wet environment Some are plant-like and contain chlorophyll while others are animal- like and can move

Protists reproduce asexually by cell division or regeneration; most protists can also reproduce sexually. Protists are difficult to classify; they are usually grouped based on characteristics shared with plants, animals, or fugi. The evolution of protists is studied through fossils and genetic material

Plant-like protists are called ALGAE; they contain chlorophyll and make their own food. Diatoms, found in fresh and salt water, make glasslike boxes

Dinoflagellates use flagella ( singular flagellum) long, thin, whiplike structures to move in their saltwater environment.

Euglenoids have characteristics of bioth plants and animals. When light is present, they can make their own food; an eye spot helps them move toward the light. In the absence of light, they can eat bacteria or other protists

Red algae- also called seaweeds, are usually many-celled, can live at depths of 200m, and contain chlorophyll and large amounts of red pigment.

Green Algae- contains large amounts of chlorophyll and can be one-celled or many- celled; some scientists hypothesize that plants evolved from green algae.

Brown Algae- many celled saltwater form called kelp. Is an important source of food and shelter for aquatic organisms.

Algae, source of food for ocean organisms, are called grasses of the ocean. Algae have an environmental impact. Algae produce oxygen through photosynthesis A result of imbalances, an algal bloom can cause environmental problems. Some people eat alae; algae are used in many cosmetic and food products.

PROTOZOANS-one celled animal protists. They are classified by how they move. Ciliates- Threadlike structures called cilia extend from their cell membranes. A paramecium has two nuclei; the micronucleus is involved in reproduction while the macronucleus controls the other cell functions. Ciliates usually eat bacteria.

FLAGELLATES- move by whipping their long flagella Many flagellates live in freshwater, and some are parasites.proterospongia grow in cell colonies and have cells that are similar in structure to cells in sponges.

Some protozoans move and eat using “false feet”, pseudopods, temporary extensions of their cytoplasm. An amoeba traps its food with pseudopods. Some shelled protozoans can push a pseudopod through a hole in the shell.

One group of protozoans has no way to move on its own. These protozoans are parasites in humans and other animals. Their complex lifecycle may have them living a part of their life in one animal and another part in a different animal.

Protozoans are important food sources for many animals. Shelled protozoans become a part of sediment layers; geologists can use them as an indicator species to help locate petroleum reserves. Some parasites can cause diseases in humans.

Funguslike protists produce spores and must take in food from outside their body; many like amoeba can move using pseudopods. Slime molds are often found on decaying vegetation in moist, cool areas. Water molds live in wet places; downy mildews can weaken or kill plants. Some funguslike protists help break down dead organisms; many cause disease in plants and animals.

FUNGI Section 2

FUNGI Fungi can be food sources or ingredients; they can also grow on spoiling food or in damp places like a shower or curtain.

Scientists are not sure how fungi are related to other organisms. Most fungi are saprophytes, feeding on dead or decaying material; some fungi are parasites, obtaining their food from living things.. Threadlike tubes called HYPHAE produce enzymes for digestion.

Fungi grow anchored in soil like plants, but do not make their own food; they grow best in warm, humid places.

Fungi can reproduce both sexually and asexually. In asexual reproduction, cell division produces spores. In sexual reproduction, the hyphae of two genetically different fungi of the same species produce spores that differ genetically from both parents.

FUNGI are classified into three groups on the type of structure formed by the joining of hyphae. 1. Club Fungi produce spores in a club shaped structure called basidium.

Sac Fungi produce spores in a small sac like structure called an ascus; yeasts can also reproduce by budding.

A zygote fungus produces spores in a round case called a sporangium.

Some fungi like penicillin, are called imperfect because they have never been observed reproducing sexually or they only reproduce asexually.

Lichens- are organisms composed of a fungus and either a green alga or a cyanobacterium; they can appear crusty, leafy or grow upright.

Lichens can be an important food source for animals. Lichens help weather, or break down, rocks. Since lichens are sensitive; they help scientists monitor pollution levels.

Some fungi form a hyphae network with plant roots called mycorrihizae; this may have allowed plants to move from water to land about 500 million years ago.

Some fungi, such as cultivated mushrooms, are food sources. Many fungi cause plant and animal diseases but they also produce antibiotics, such as penicillin, which can fight disease. Fungi are important as decomposers, recycling organic matter.