Algae
hideAlgae (pronounced /ˈældʒiː/; singular alga /ˈælɡə/, Latin for "seaweed") are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms. The largest and most complex marine forms are called seaweeds. They are photosynthetic, like plants, and "simple" because they lack the many distinct organs found in land plants. For that reason they are currently excluded from being considered plants.
Though the prokaryotic Cyanobacteria (commonly referred to as Blue-green Algae) were traditionally included as "Algae" in older textbooks, many modern sources regard this as outdated and restrict the term Algae to eukaryotic organisms. All true algae therefore have a nucleus enclosed within a membrane and chloroplasts bound in one or more membranes. Algae constitute a paraphyletic and polyphyletic group, as they do not include all the descendants of the last universal ancestor nor do they all descend from a common algal ancestor, although their chloroplasts seem to have a single origin.
Algae lack the various structures that characterize land plants, such as phyllids and rhizoids in nonvascular plants, or leaves, roots, and other organs that are found in tracheophytes. Many are photoautotrophic, although some groups contain members that are mixotrophic, deriving energy both from photosynthesis and uptake of organic carbon either by osmotrophy, myzotrophy, or phagotrophy. Some unicellular species rely entirely on external energy sources and have limited or no photosynthetic apparatus.
Nearly all algae have photosynthetic machinery ultimately derived from the Cyanobacteria, and so produce oxygen as a by-product of photosynthesis, unlike other photosynthetic bacteria such as purple and green sulfur bacteria. Fossilized filamentous algae from the Vindhya basin have been dating back to 1.6 to 1.7 billion years ago.
The first alga to have its genome sequenced was Cyanidioschyzon merolae.
For more information about Algae, read the full article at
Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.
News tagged with algae
'Safety valve' protects photosynthesis from too much light
Nov 25, 2009 |
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Photosynthetic organisms need to cope with a wide range of light intensities, which can change over timescales of seconds to minutes. Too much light can damage the photosynthetic machinery and cause cell death. Scientists ...
NASA Develops Algae Bioreactor as a Sustainable Energy Source
Nov 18, 2009 |
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(PhysOrg.com) -- As a clean energy alternative, NASA invented an algae photo-bioreactor that grows algae in municipal wastewater to produce biofuel and a variety of other products.
Researchers turn algae into high-temperature hydrogen source
Nov 12, 2009 |
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In the quest to make hydrogen as a clean alternative fuel source, researchers have been stymied about how to create usable hydrogen that is clean and sustainable without relying on an intensive, high-energy ...
15,000 reasons to worry about invasive species
Nov 09, 2009 |
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A day at the beach in Wisconsin's North Woods didn't used to go like this. Candy Dailey spent a Fourth of July holiday splashing with grandkids on the sandy shore of Lake Metonga when she felt a nasty sting on her foot.
Caribbean, Gulf spared widespread coral damage
Nov 06, 2009 |
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(AP) -- Lower-than-feared sea temperatures this summer gave a break to fragile coral reefs across the Caribbean and the central Gulf of Mexico that were damaged in recent years, scientists said Thursday.
Clean algae biofuel project leads world in productivity
Nov 04, 2009 |
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Australian scientists are achieving the world's best production rates of oil from algae grown in open saline ponds, taking them a step closer to creating commercial quantities of clean biofuel for the future.
Algae may be secret weapon in climate change war
Oct 22, 2009 |
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Driven by fluctuations in oil prices, and seduced by the prospect of easing climate change, experts are ramping up efforts to squeeze fuel out of a promising new organism: pond scum.
Killer algae a key player in mass extinctions
Space & Earth / Earth Sciences
Oct 19, 2009 |
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Algae, not asteroids, were the key to the end of the dinosaurs, say two Clemson University researchers. Geologist James W. Castle and ecotoxicologist John H. Rodgers have published findings that toxin producing ...
Eutrophication affects diversity of algae
Oct 19, 2009 |
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Eutrophication of the seas may have an impact on genetic variation in algae, research at the University of Gothenburg shows.
Last time carbon dioxide levels were this high: 15 million years ago, scientists report
Space & Earth / Earth Sciences
Oct 08, 2009 |
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You would have to go back at least 15 million years to find carbon dioxide levels on Earth as high as they are today, a UCLA scientist and colleagues report Oct. 8 in the online edition of the journal Science.
NASA Conducts Airborne Science Aboard Zeppelin Airship
Oct 07, 2009 |
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(PhysOrg.com) -- NASA launched its first airborne science mission this week featuring a 246-foot-long Zeppelin NT airship equipped with two imaging instruments to learn more about environmental conditions in the San Francisco ...
Fill 'er up -- with algae
Oct 07, 2009 |
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Imagine filling up your car with fuel that comes from inexpensive algae that grow quickly, don't use up freshwater supplies and can be cultivated in areas where they won't compete with traditional food crops, ...
A new day dawned fast: Recovery from marine mass extinction happened much faster than thought
Space & Earth / Earth Sciences
Oct 02, 2009 |
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(PhysOrg.com) -- In 1979, Luis Alvarez and his collaborators stunned the world with their discovery that an asteroid impact 65 million years ago probably killed off the dinosaurs and much of the the world's ...
Coral bleaching increases chances of coral disease
Oct 01, 2009 |
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Mass coral bleaching has devastated coral colonies around the world for almost three decades. Now scientists have found that bleaching can make corals more susceptible to disease and, in turn, coral disease ...
Algae and pollen grains provide evidence of remarkably warm period in Antarctica's history
Space & Earth / Earth Sciences
Oct 01, 2009 |
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For Sophie Warny, LSU assistant professor of geology and geophysics and curator at the LSU Museum of Natural Science, years of patience in analyzing Antarctic samples with low fossil recovery finally led to a scientific breakthrough. ...
