Plantlike Protists: Red, Brown and Green Algae
§ have cell walls and photosynthetic pigments
§ highly specialized tissue
§ multicellular like plants
§ 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
§ phylum Phaeophyta meaning "dusky plants"
§ contain chlorophyll a and c plus a brown accessory pigment called
► 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.
§ 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:
Unicellular Green Algae - Chlamydomonas which is a single-celled green alga growing in ponds, ditches and, wet soil
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.
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
§ 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