Green algae

Green algae are a large, informal grouping of algae consisting of the Chlorophyte and Charophyte algae, which are now placed in separate divisions.

Overview

The land plants, or Embryophyta, are thought to have emerged from the Charophytes.<ref>Becker, B & Marin, B (2009). "Streptophyte Algae and the Origin of Embryophytes". Annals of Botany. 103 (7): 999–1004. doi:10.1093/aob/mcp044. PMC 2707909. PMID 19273476.</ref> Therefore, in modern classification systems, green algae are considered relatives of the land plants.

Characteristics

Green algae are eukaryotic organisms that follow a reproduction cycle that involves alternation of generations.<ref>Hoek, C. van den, Mann, D.G. and Jahns, H.M. (1995). Algae An Introduction to Phycology. Cambridge University Press, Cambridge.</ref> They contain two forms of chlorophyll, chlorophyll a and chlorophyll b, which gives them a bright green color. They also contain the accessory pigments beta carotene (a yellow pigment) and xanthophylls (yellow-green pigments).

Classification

The green algae include unicellular and multicellular flagellates, usually but not always with two flagella per cell, as well as various colonial, coccoid, and filamentous forms. In the Charales, the closest relatives of higher plants, full differentiation of tissues occurs.<ref>Lewis, L.A & McCourt, R.M. (2004). "Green algae and the origin of land plants". American Journal of Botany. 91 (10): 1535–1556. doi:10.3732/ajb.91.10.1535. PMID 21652308.</ref>

Uses

Green algae are used in many cultures for various purposes. For example, Chlorella and Spirulina are used as dietary supplements. Some species of green algae, particularly of genera Trebouxia of the class Trebouxiophyceae and Chlorella of the class Chlorophyceae, are symbionts with fungi to form lichen.

See also

• Algae
• Chlorophyte
• Charophyte
• Embryophyta
• Chlorophyll
• Chlorella
• Spirulina
• Trebouxia
• Lichen

References

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  Green algae
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  Intertidal green algae
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  Conjugate algae
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  Freshly harvested algae