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Protists
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Protists
- a protist is a one- or many- celled organism that lives in wet surroundings.
- all protists have eukaryotic cells (cells with a nucleus and other membrane-bound organelles)
- protists may be plant-like, animal-like, or fungus-like
(Copy Table 1 on page 211)
- Some protists reproduce asexually, resulting in genetically identical offspring
- Some protists reproduce sexually, and produce genetically different offspring
- Scientists think that protists evolved from a one-celled organism with a nucleus and other structures.
• - Plantlike protists have cell walls and contain chlorophyll
• - Animal-like protists are separated into groups according to how they move
• - Funguslike protists have characteristics found in both fungi and protists
• Algae are plantlike protists. - algae contain chlorophyll and produce oxygen as a
result of photosynthesis
- There are many different types of algae. They include diatoms, dinoflagellates, red or green algae commonly called seaweed, and brown algae known as kelp.
• - Dinoflagellates have two flagellum, long, thin, whiplike structures used for movement.
• - Protozoans are one-celled, animal-like protists - Protozoans can live in water, soil, and in living or dead organisms
• - Protists called ciliates are covered in cilia, short, thread-like structures that extend from the cell membrane.
• - cilia help the organism to move quickly in any direction.
• - a Paramecium is a ciliate that has two nuclei
• - Paramecium are found in freshwater environments and consume bacteria.
• - Pseudopods are extensions of cytoplasm used by some protists to move through their environment.
• - the word “pseudopod” means “false foot”
http://www.youtube.com/watch?v=PsYpngBG394
• Fungi
- Fungi are organisms that grow in soil and have a cell wall. Because they do not contain chlorophyll or have the structures of plants, they cannot be categorized as plants.
• - Most species of fungi are many-celled
• - Hyphae are the mass of threadlike tubes which form the body of a fungus
• - Most fungi are saprophytes.
- A saprophyte is an organism that gets food by absorbing dead or decaying tissues of other organisms
- Some species of fungi are parasites, obtaining their food directly from living things
• - Fungi can reproduce sexually or asexually. In either case, fungi reproduce through spores
• - A spore is a waterproof reproductive cell that can grow into a new organism.
http://www.youtube.com/watch?v=A1uQ5rXmbO8
• - Common fungi include mushrooms and yeast.
- yeasts can reproduce by budding, a form of asexual reproduction in which a new organism forms on the side of a parent organism.
Lichen• - a lichen is an organism that is made up of
fungus and either a green algae or a cyanobacterium.
- lichens are food sources for many animals. - lichens are used to determine pollution levels in
an area
• http://www.youtube.com/watch?v=Te4qnLkHnS4