alga

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.