Algae

:This article is about an organism. See algae programming language for a programming language in computing.

Related Topics:
Algae programming language - Programming language - Computing

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The algae (singular alga) comprise several different groups of living organisms usually found in wet places or water bodies and that capture light energy through photosynthesis, converting inorganic substances into simple sugars with the captured energy. Algae were traditionally regarded as simple plants, and some are closely related to the higher plants. Others appear to represent different protist groups, alongside other organisms that are traditionally considered more animal-like (protozoa). Thus algae do not represent a single evolutionary group, but a level of organization that may have developed several times in the early evolutionary history of life on earth.

Related Topics:
Photosynthesis - Plant - Higher plant - Protist - Protozoa

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Algae range from single-celled organisms to multi-cellular organisms, some with fairly complex differentiated form and called seaweeds. All lack leaves, roots, flowers, and other organ structures that characterize higher plants. They are distinguished from other protozoa in that they are photoautotrophic, although this is not a hard and fast distinction as some groups may contain members that are mixotrophic, deriving energy both from photosynthesis as well as through the uptake of organic carbon either by osmotrophy, myzotrophy, or phagotrophy. Some unicellular algae rely entirely on external energy sources and have reduced or lost their photosynthetic apparatus.

Related Topics:
Seaweed - Leaves - Root - Flower - Protozoa - Photoautotrophic - Mixotrophic - Osmotrophy - Myzotrophy - Phagotrophy

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All algae have photosynthetic machinery ultimately derived from the cyanobacteria, and so produce oxygen as a by-product of photosynthesis, unlike other, non-cyanobacterial photosynthetic bacteria.

Related Topics:
Cyanobacteria - Oxygen

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Algae are common in terrestrial as well as aquatic environments, but usually inconspicuous on the land and more common in moist, tropical climates (see, however Lichens). The various sorts of algae play significant roles in aquatic ecology. Microscopic forms that live suspended in the water column, called phytoplankton, provide the food base for most marine food chains. In very high densities (so-called algal blooms) they may discolor the water and outcompete or poison other life forms. The seaweeds grow mostly in shallow marine waters; some are used as human food or are harvested for useful substances such as agar or fertilizer. The study of algae is called phycology or algology.

Related Topics:
Lichen - Phytoplankton - Food chain - Algal bloom - Agar

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