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Biology 2014-2015

Red, Brown, and Green Algae

SWS Biology
SWS Life Science





Plantlike Protists:  Red, Brown and Green Algae

    have cell walls and photosynthetic pigments

    highly specialized tissue

    multicellular like plants


Red Algae

    phylum Rhodophyta meaning "red plants"

    contain chlorophyll a and reddish accessory pigment called phycobilin

       absorb blue light which allows red algae to live deeper in the ocean

    found in water from the polar regions to the tropics

    important role in the formation of coral reefs

       provide nourishment for coral animals


Brown Algae

    phylum Phaeophyta meaning "dusky plants"

    contain chlorophyll a and c plus a brown accessory pigment called fucoxanthin

       dark, yellow-brown color

    largest and most complex of the algae

    found in cool, shallow coastal waters of temperate or arctic

    largest known alga is giant kelp which grows more than 60 meters in length

    Sargassum forms huge floating mats many kilometers long in the Atlantic Ocean

    Fucus, or rockweed attaches to the bottom by a holdfast.


Green Algae

    phylum Chlorophyta meaning "green plants"

    contain chlorophyll a and b

    cell walls contain cellulose

    store food in the form of starch

    found in fresh and salt water, and even moist areas on land

    Three Types include:

1.      Unicellular Green Algae - Chlamydomonas which is a single-celled green alga growing in ponds, ditches and, wet soil

2.      Colonial Green Algae - Spirogyra (freshwater) forms long thread like colonies called filaments resembling cells that are stacked like aluminum cans placed end to end.  Volvox consist of as few as 500 to as many as 50,000 cells arranged to form hollow spheres.

3.      Multicellular Green Algae - Ulva or "sea lettuce" is a bright-green marine alga that is commonly found along rocky seacoasts


Human Uses of Algae

    major food source for life in the ocean

    brown kelp forests are home to many animal species

    performs about half of all the photosynthesis thus providing much of Earth's oxygen

    rich in vitamin C and iron

    used to treat stomach ulcers, high blood pressure, arthritis

    used to make plastics, waxes, transistors, deodorants, paints, lubricants, and even artificial wood

    agar, derived from seaweed, thickens the nutrient mixtures used to grow bacteria

    used in food products such as ice cream, salad dressing, pudding, candy bars, pancake syrup and eggnog

    the red algae Porphyra, called nori in Japanese, is used to wrap rice, fish and vegetables to make sushi