Chapter 8

Protists and Fungi

Protists

• Protist- one or many celled organism that lives in moist/wet surroundings.– Eukaryotic cells– Asexual reproduction by cell division or sexual

reproduction with meiosis

Plant-like Protists

• Algae- plant like and contain chlorophyll• Diatoms- found in fresh or salt water• Dinoflagellates- have 2 flagellum, or long whip like

structures for movement• Euglenoids- have characteristics of plants and animals• Red algae- contain chlorophyll but produce red pigment and

can live 200m deep in ocean• Green algae- contain large amounts of chlorophyll• Brown algae- chlorophyll and brown pigment. Found in

cool, saltwater environments. Important food for fish– Ex: kelp

Animal-like Protists

• Protozoans- one celled, animal like protists• Ciliates- have cilia to move around. • Flagellates- whip long flagella to move• Pseudopods- move and feed using temporary

extensions of cytoplasm

Diseases

• Protozoans that cause disease can be transmitted by flies or biting insects or found in contaminated water

Importance of Algae

• Produce oxygen during photosynthesis• Are a food source for many organisms

Slime Molds

• Fungi-like protist that forms delicate, weblike structures on the surface of their food supply– Usually found on decaying logs– Often brightly colored

Water Molds and Downy Mildews

• Fungi-like protists that lives in water or moist places

• Grow as mass of threads over plant or animal;• Some are parasites, decomposers

Importance of Fungi-like Protists

• Break down dead organisms• Cause diseases in animals/plants– Lesions in fish

• Caused the Irish Pot ato Famine during the 1840s

Fungi

• Many celled• Hyphae- when body of fungus is mass of many

celled, thread like tubes• Saprophytes- organisms that obtain food by

absorbing dead or decaying tissues of other organisms

• Grow best in warm, humid areas

Fungi Reproduction

• Asexual and sexual reproduction use production of spores

• Spore- waterproof reproductive cell that can grow into new organism

Classification

• Classified into 3 groups– Club fungi spores

produced in club-shaped structure called basidium

– Sac fungi yeast, molds, morels, truffles. Spores produced in a little, sac like structure called ascus

– Zygote fungi produce spores in a round spore case called sporangium on tips of upright hyphae

Lichens

• An organism made of a fungus and either a green algae or cyanobacterium– Relationship where both benefits• Cyanobacterium or algae get moist, protected place to

live• Fungus gets food made by green algae or

cyanobacterium

– Important food source for animals like caribou and musk oxen

– Help weather rock to create soil

Fungi and Plants

• Fungi interact with plant roots to form network of hyphae and roots called mycorrhizae– Fungus helps plants absorb more of certain

nutrients from soil, while plant provides food and nutrients to fungi

Importance of Fungi

• Food source (but can be poisonous!)• Used to make cheese• Yeast creates bread, alcohol (remember

fermentation!)• Can cause disease that destroys crops or affects

humans (athlete's foot, ringworm)• Can produce antibiotics like pencillin• Decompose organic materials and return

nutrients to soil.