alga

(noun)

any of many aquatic photosynthetic organisms, whose size ranges from a single cell to giant kelps and whose form is very diverse

Related Terms

  • thalloid
  • basionym

Examples of alga in the following topics:

  • Streptophytes and Reproduction of Green Algae

    • Land plants and closely-related green algae (charophytes) are classified as Streptophytes; the remaining green algae are chlorophytes.
    • The brown, red, and gold algae, however, have been reassigned to the Protista kingdom.
    • The position of green algae is more ambiguous.
    • Green algae contain the same carotenoids and chlorophyll a and b as land plants, whereas other algae have different accessory pigments and types of chlorophyll molecules in addition to chlorophyll a.
    • Both green algae and land plants also store carbohydrates as starch.
  • Archaeplastida

    • Red algae and green algae are included in the supergroup Archaeplastida.
    • The red algae life cycle is an alternation of generations.
    • Other red algae exist in terrestrial or freshwater environments.
    • The most abundant group of algae is the green algae.
    • Describe the relationship between red algae, green algae, and land plants
  • Edible Algae

    • Edible algae have been used as food for centuries in many coastal regions all over the world.
    • Cyanobacteria are sometimes called blue-green algae but they are prokaryotic organisms and are not true algae.
    • Seaweeds are edible algae that have been used for centuries as food in many coastal regions all over the world.
    • They may belong to one of three groups of multicellular algae: red, green or brown.
    • They are usually of marine origin since freshwater algae are often poisonous.
  • Chromalveolata: Stramenopiles

    • Stramenophiles include photosynthetic marine algae and heterotrophic protists such as diatoms, brown and golden algae, and oomycetes.
    • Like diatoms, golden algae are largely unicellular, although some species can form large colonies.
    • The brown algae are primarily marine, multicellular organisms that are known colloquially as seaweeds.
    • Giant kelps are a type of brown algae.
    • Describe characteristics of the following Stramenophiles:  diatoms, brown algae, golden algae, and oomycetes
  • The Phosphorus Cycle

    • Phosphorous can be transfered to other organisms when they consume the plants and algae.
    • When phosphorous levels are high, algae and plants reproduce rapidly.
    • As phosphorous levels begin to increase at the end of the summer, primary plants and algae begin to rapidly grow again.
    • Artificial phosphorous can cause over growth of algae and plants in aquatic ecosytems.
    • The bright green color of the water is the result of algae blooms in response to the addition of phosphorous based fertilizers.
  • Charales

    • Green algae in the order Charales, and the coleochaetes, microscopic green algae that enclose their spores in sporopollenin, are considered the closest-living relatives of embryophytes.
    • In Charales, large cells form the thallus: the main stem of the alga.
    • New information from recent, extensive DNA sequence analysis of green algae indicates that the Zygnematales are more closely-related to the embryophytes than the Charales.
    • A representative charophyte alga, Chara, is a noxious weed in Florida, where it clogs waterways.
  • The Evolution of Plastids

    • The chloroplasts of red and green algae, for instance, are derived from the engulfment of a photosynthetic cyanobacterium by an early prokaryote .
    • Some of the major groups of algae became photosynthetic by secondary endosymbiosis; that is, by taking in either green algae or red algae as endosymbionts.
    • Chlorarachniophytes are rare algae indigenous to tropical seas and sand.
    • In fact, secondary endosymbiosis of green algae also led to euglenid protists, whereas secondary endosymbiosis of red algae led to the evolution of dinoflagellates, apicomplexans, and stramenopiles.
    • (a) Red algae and (b) green algae (visualized by light microscopy) share similar DNA sequences with photosynthetic cyanobacteria.
  • Algae

    • However notable examples of algae acting as pathogens are known.
    • For example Cephaleuros which is a genus of parasitic thalloid alga comprising approximately 14 species.
    • Examples of algae acting as a mammalian pathogen are known as well, notably the disease Protothecosis.
    • Protothecosis is a disease found in dogs, cats, cattle, and humans caused by a type of green alga known as Prototheca that lacks chlorophyll.
    • The grayish-white and darker "crusts" are lichens of the genus Strigula resulting from fungal colonization of the alga.
  • Carotenoids and Phycobilins

    • Photosynthesis in many plants and algae depend on chlorophylls which absorb light closer to the ultraviolet side of the spectrum, and emit light in the green end of the spectrum.
    • Chromoplasts of plants and some other photosynthetic organisms like algae, some bacteria, and some fungi .
    • They serve two key roles in plants and algae: they absorb light energy for use in photosynthesis, and they protect chlorophyll from photodamage.
    • Phycobilins (from Greek: φ (phykos) meaning "alga", and from Latin: bilis meaning "bile") are chromophores (light-capturing molecules) found in cyanobacteria and in the chloroplasts of red algae, glaucophytes and some cryptomonads (though not in green algae and higher plants).
    • The color of the mats of algae and bacteria is due to the ratio of chlorophyll to carotenoid molecules produced by the organisms.
  • Oxygenic Photosynthesis

    • In plants, algae and cyanobacteria, photosynthesis releases oxygen .
    • Although there are some differences between oxygenic photosynthesis in plants, algae, and cyanobacteria, the overall process is quite similar in these organisms.
    • In plants, algae and cyanobacteria, photosynthesis releases oxygen.
    • Although there are some differences between oxygenic photosynthesis in plants, algae, and cyanobacteria, the overall process is quite similar in these organisms.
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