The Heterokontophyta (Phaeophyta or brown algae, singular: brown alga) is a large group of mostly marine multicellular algae, including many seaweeds of colder Northern Hemisphere waters. They play an important role in marine environments both as food, and for the habitats they can form. For instance Macrocystis, a member of the Laminariales or kelps, may reach 60 m in length, and forms prominent underwater forests. Another example is Sargassum, which creates unique habitats in the tropical waters of the Sargasso Sea. This is one of the few areas where a large biomass of brown algae may be found in tropical waters. Many brown algae such as members of the order Fucales are commonly found along rocky seashores. Some members of the division are used as food for humans.
Worldwide there are about 1500 — 2000 brown seaweed species.[1]
Brown algae belong to a very large group called the hererokonts, a eukaryotic group of organisms distinguished most prominently by having chloroplasts surrounded by four membranes, suggesting an origin from a symbiotic relationship between a basal eukaryote and another eukaryotic organism. Most brown algae contain the pigment fucoxanthin, which is responsible for the distinctive greenish-brown color that gives them their name. Brown algae are unique among heterokonts in developing into multicellular forms with differentiated tissues, but they reproduce by means of flagellate spores, which closely resemble other heterokont cells. Genetic studies show their closest relatives to be the yellow-green algae.
Phaeophyta first appear in the fossil record in the Mesozoic, possibly as early as the Jurassic. Their occurrence as fossils is rare due to their generally soft-bodied habit, and scientists continue to debate the identification of some finds. Other algae groups, such as the red algae and green algae have a number of calcareous members, which are more likely to leave evidence in the fossil record than the soft bodies of the brown algae. Miocene fossils of a soft-bodied brown macro algae, Julescrania, have been found well-preserved in Monterey Formation diatomites, but few other certain fossils, particularly of older specimens are known in the fossil record
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2007-03-14 04:29:23
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answer #1
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answered by Hope Summer 6
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The Heterokontophyta (Phaeophyta or brown algae, singular: brown alga) is a large group of mostly marine multicellular algae, including many seaweeds of colder Northern Hemisphere waters.
They play an important role in marine environments both as food, and for the habitats they can form.
For instance Macrocystis, a member of the Laminariales or kelps, may reach 60 m in length, and forms prominent underwater forests.
Another example is Sargassum, which creates unique habitats in the tropical waters of the Sargasso Sea.
This is one of the few areas where a large biomass of brown algae may be found in tropical waters.
Many brown algae such as members of the order Fucales are commonly found along rocky seashores.
Some members of the division are used as food for humans.
Worldwide there are about 1500 to 2000 brown seaweed species.
Brown algae belong to a very large group called the hererokonts, a eukaryotic group of organisms distinguished most prominently by having chloroplasts surrounded by four membranes, suggesting an origin from a symbiotic relationship between a basal eukaryote and another eukaryotic organism.
Most brown algae contain the pigment fucoxanthin, which is responsible for the distinctive greenish-brown color that gives them their name.
Brown algae are unique among heterokonts in developing into multicellular forms with differentiated tissues, but they reproduce by means of flagellate spores, which closely resemble other heterokont cells.
Genetic studies show their closest relatives to be the yellow-green algae.
Phaeophyta first appear in the fossil record in the Mesozoic, possibly as early as the Jurassic.
Their occurrence as fossils is rare due to their generally soft-bodied habit, and scientists continue to debate the identification of some finds.
Other algae groups, such as the red algae and green algae have a number of calcareous members, which are more likely to leave evidence in the fossil record than the soft bodies of the brown algae.
Miocene fossils of a soft-bodied brown macro algae, Julescrania, have been found well-preserved in Monterey Formation diatomites, but few other certain fossils, particularly of older specimens are known in the fossil record
2007-03-14 04:26:31
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answer #2
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answered by surez 3
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Common name: Brown algae
Section: Protists
Kingdom: Protista
Phylum: Phaeophyta
Relatives: Red and green algae,
other: protists.
2007-03-14 04:47:51
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answer #3
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answered by onoscity 4
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The other name of Brown algae is phaenophyta.
2007-03-14 06:22:59
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answer #4
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answered by sagar k 1
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Heterokontophyta or Phaeophyta
Most brown algae contain the pigment fucoxanthin, which is responsible for the distinctive greenish-brown color that gives them their name
2007-03-14 04:32:55
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answer #5
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answered by ANITHA 3
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Phaeophyta
2007-03-17 16:54:12
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answer #6
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answered by Gayathri 4
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there r 3 classes of bacteria chlorophycaea - green algae phaeophycae -brown algae and rhodophycaea- red algae. phaeophycae contains carotenoids, xanthophill, FUCOXANTHIN,and chlorophyll b and so it is brown in colour.
2007-03-14 04:32:21
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answer #7
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answered by jkool 1
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Phaeophyceae
2007-03-15 21:19:47
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answer #8
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answered by Anonymous
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Phaeophycophytes.
2007-03-16 00:03:11
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answer #9
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answered by Aksum 2
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Other names these organisms are known as:
Dulse, lava bread, nori
2007-03-14 16:36:24
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answer #10
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answered by dhanush 2
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