Algae stationKEY

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					                               Algae (the seaweeds)
                                    Station 2
   Open the “A look at the algae” PowerPoint. Use the PowerPoint and the algae article found at
    your station to answer the following questions.
   Observe any other resources found at your station.

        1. What is meant by “primitive plant”?
            A primitive plant is a plant that does not have true roots, stems and
            leaves.
        2. Why is the word “algae” confusing?
            The word algae is confusing because biologists use the term to
            describe many different groups that are not related to one another.
        3. What is a thallus?
            A thallus is the plant body of an alga. It contains no vascular tissue
            and is not separated into roots, stems, or leaves.
        4. What is a holdfast?
            A holdfast is the lowermost cell of a thallus filament that anchors the
            filament to rocks or mud.
        5. List a few places you might go to find algae.
            Fast-flowing streams, lakes, quiet ponds, drainage ditches, near
        shores, tidal zones
        6. In what ways are algae important to us?
            Algae supply oxygen through photosynthesis.
        7. What four (4) characteristics do biologists use to classify algae into
            groups?
            (i)     color
            (ii)    type of storage product in the cells
            (iii)   size
            (iv)    structure of the thallus
        8. What is the difference between isogametes and heterogametes?
            Isogametes are when the sperm and egg cells are alike in size and
            shape.
            Heterogametes are when the sperm and egg cells are different in size
            and shape.
        9. What are three (3) asexual methods of reproduction in algae?
            (i)     mitosis
            (ii)    fragmentation
            (iii)   zoospores
        10. What is a zoospore?
            A zoospore is a small reproductive cell with at least two flagella.
        11. What types of plant bodies are found in green algae?
            Chlorophylls and other pigments that store starch in their cells.
        12. Why do biologists think that ancient green algae were the ancestors of
            higher plants?
            Algae also store starch (like true plants!!) and contain the same
            pigments as green algae.
    FILL IN THE CHART BELOW USING THE ALGAE POWERPOINT

Common name    Phylum Name                Characteristics (list…)
                                Most abundant & widely distributed of
                                 all algae
 Green algae
               Chlorophyta      unicellular & multicellular
                                approx. 6000 species
                                contain cholorphylls (like higher plants)
                                store starch in their cells (like higher
                                 plants)
                                Believed higher plants evolved from
                                 green algae.

                                Many species grow in cool waters along
                                 rocky coasts (anchored to rocks by their
 Brown algae
               Phaeophyta        root-like parts & gas-filled structures
                                 that function as floats ).
                                important source of iodine.
                                Can be used as fertilizer or as food for
                                 humans.Other species are a source of
                                 algin, which is used to thicken ice crème
                                 and other foods.

                                Multicellular but never as large as the
                                 largest brown algae
  Red algae
               Rhodophyta       More complex that other forms of algae
                                Most live in salt water but in warmer
                                 waters and greater depths
                                Very beautiful colors (red, green, yellow,
                                 purple), feathery
                                Cell walls contain cellulose as well as
                                 other substances like agar (thickener in
                                 foods like ice crème, puddings, and cake
                                 icing; medium on which bacteria and
                                 fungi are grown in laboratories)
                                Carrageenan is another product of red
                                 algae which is a type of stabilizing agent
                                 used to prevent separation of food
                                 mixtures (i.e. chocolate and milk)

				
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