algae:
Types of Algae
The simplest algae are single cells (e.g., thediatoms); the more complex forms consist of many cells grouped in a spherical colony (e.g.,Volvox), in a ribbonlike filament (e.g.,Spirogyra), or in a branching thallus form (e.g.,Fucus). The cells of the colonies are generally similar, but some are differentiated for reproduction and for other functions. Kelps, the largest algae, may attain a length of more than 200 ft (61 m).Euglenaand similar genera are free-swimming one-celled forms that contain chlorophyll but that are also able, under certain conditions, to ingest food in an animallike manner. The green algae include most of the freshwater forms. Thepond scum, a green slime found in stagnant water, is a green alga, as is the green film found on the bark of trees. The more complex brown algae and red algae are chiefly saltwater forms; the green color of the chlorophyll is masked by the presence of other pigments. Blue-green algae have been grouped with other prokaryotes in the kingdomMoneraand renamedcyanobacteria.
See the separate phyla (divisions)Chlorophyta,Euglenophyta,Dinoflagellata,Chrysophyta,Phaeophyta,Rhodophyta.
Sections in this article:
- Introduction
- Types of Algae
- Uses of Algae
- Bibliography
The Columbia Electronic Encyclopedia,6th ed. Copyright © 2023, Columbia University Press. All rights reserved.
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