Difference Between Red Algae and Green Algae

Main Difference

The main difference between red algae and green algae is that red algae generally have chlorophyll d, chlorophyll a and phycoerythrin while green algae have chlorophyll a, chlorophyll b, and xanthophylls.

Red Algae vs. Green Algae

Red algae comprise chlorophyll d, chlorophyll a and phycoerythrin and generally red whereas green algae have chlorophyll a, chlorophyll b, and xanthophylls and appear generally green in color. Red algae include many seaweeds that are chiefly red while green algae refer as photosynthetic algae which comprise chlorophyll and store starch in discrete chloroplasts. Red algae found in marine habitats; on the other hand, green algae mostly live in freshwater. Red algae are primarily multicellular; on the contrary, green algae contain unicellular species. This cellular structure is also a difference between red algae and green algae. Red algae are sessile and attach to the substrate while green algae are motile and contain flagella which help in movement. As both red and green algae contain chlorophyll, so the thylakoids of red algae are unstacked, on the flip side, green algae contain stacked thylakoids of 2-20. Red algae also do not produce motile stages during their life cycle, but green algae form motile sperms with multiple numbers of flagella. Red algae stock food in the form of floridean starch while green algae reserve food in the form of starch. The cell wall of red algae is a form of sulfated phycocolloids and cellulose whereas green algae mainly have cellulose in its cell wall.

Comparison Chart

Red AlgaeGreen Algae
A large group of algae that contains many seaweeds appear as mainly red.Photosynthetic algae which comprise chlorophyll and store starch in discrete chloroplasts, appear as green in color.
Habitat
Found in marineLive in freshwater
Store Food
In the form of floridean starchIn the form of starch
Thylakoids
UnstackedStacked thylakoids of 2-20
Cellular Structure
Mainly multicellularUnicellular species
Motility
SessileMotile and contain flagella
Cell Wall
Composed of sulfated phycocolloids and celluloseComposed of cellulose
Pigments
Chlorophyll d, chlorophyll a and phycoerythrinChlorophyll a, chlorophyll b, and xanthophylls
Phylum
RhodophytaChlorophyta
Examples
Coralline algae, Irish moss, dulse (Palmaria Palmata), etc.Codium sp., sea lettuce, which commonly found in tidal pools, etc

What is Red Algae?

A large group of algae that contains many seaweeds appear as mainly brilliant red. The red color in red algae is due to the presence of photosynthetic pigment phycoerythrin. Further, red algae comprise pigments chlorophyll d and chlorophyll a. Red algae belong to phylum Rhodophyta. Red algae found in marine habitats in the deeper sea because of their ability to absorb blue light. Red algae in some Asian countries used as food additives because of high vitamin and protein content. Red algae are primarily multicellular, and this cellular structure is also the main difference in the three types of algae. Red algae are sessile and mainly attach to their substrate. As red algae contain chlorophyll, so the thylakoids of red algae are unstacked. Red algae play a vital role in the making of tropical reefs. As red algae are sessile, so during their life cycle, red algae also do not produce motile stages. Red algae stock food in the form of floridean starch. Red algae are also used to produce agar. The cell wall of red algae is a form of sulfated phycocolloids and cellulose.

What is Green Algae?

Photosynthetic algae which comprise chlorophyll and store starch in discrete chloroplasts, appear as green in color. This color is due to the occurrence of chlorophyll, but in unfavorable conditions, they may appear as red. Additionally, green algae have chlorophyll a, chlorophyll b, and xanthophylls as their pigments. Green algae belong to phylum Chlorophyta. Green algae found in humid soil, freshwater and some are found in marine water also. Green algae may be present in unicellular or multicellular or have colonial form. They have flagella; long or threadlike, because they are motile, which helps them in moving. Green algae absorb red light, which is low length energy wavelength than the red algae. Green algae are found in rocks or low tide areas, as red light cannot penetrate much deeper in the sea. Some green algae also show symbiotic association with fungi and lichens. Green algae are used and considered as potential biofuels.

Key Differences

  1. Red algae are a large group of algae that includes many seaweeds appear as mainly red whereas green algae are a photosynthetic alga which comprises chlorophyll and store starch in discrete chloroplasts, appear as green in color.
  2. Red algae comprise chlorophyll d, chlorophyll a and phycoerythrin whereas green algae have chlorophyll a, chlorophyll b, and xanthophylls.
  3. Red algae found in marine habitats; on the other hand, green algae mostly live in freshwater.
  4. Red algae are primarily multicellular, on the contrary, green algae contain unicellular species.
  5. Red algae are sessile and attach to the substrate while green algae are motile and contain flagella which help in movement.
  6. As both red and green algae contain chlorophyll, so the thylakoids of red algae are unstacked, on the flip side, green algae contain stacked thylakoids of 2-20.
  7. Red algae also do not produce motile stages during their life cycle, but green algae form motile sperms with multiple numbers of flagella.
  8. The cell wall of red algae is a form of sulfated phycocolloids and cellulose whereas green algae mainly have cellulose in its cell wall.
  9. Red algae stock food in the form of floridean starch while green algae reserve food in the form of starch.

Conclusion

Above discussion concludes that red algae comprise chlorophyll d, chlorophyll a and phycoerythrin and generally red while green algae have chlorophyll a, chlorophyll b, and xanthophylls and appear generally green in color.

Janet White

Janet White is a writer and blogger for Difference Wiki since 2015. She has a master's degree in science and medical journalism from Boston University. Apart from work, she enjoys exercising, reading, and spending time with her friends and family. Connect with her on Twitter @Janet__White

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