Questions and Answers
Which of the following statements about Euglenophyta is true?
What is the primary feature of diatoms?
They are encased by a silica shell known as a frustule.
Pyrrophyta are only found in freshwater environments.
False
What reproductive method is associated with red algae?
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What is one example of brown algae?
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Yellow-green algae appear lighter in color due to the lack of a certain ______.
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Which type of algae typically lives in freshwater environments?
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Study Notes
Euglenophyta
- Euglena are protists found in fresh and salt water, with both autotrophic (photosynthetic) and heterotrophic (feeding on organic material) capabilities.
- Covering consists of a protein-rich pellicle instead of a cell wall.
- Characteristics of photosynthetic euglenoids include an eyespot, flagella, and organelles like nucleus and chloroplasts.
- Scientifically linked to endosymbiotic relationships with green algae, leading to debate on their classification.
Chrysophyta
- Comprises golden-brown algae and diatoms, totaling around 100,000 species in fresh and salt water.
- Diatoms are highly abundant, forming plankton and encased in unique silica shells (frustules).
- Golden-brown algae, while fewer, rival diatoms in ocean productivity and are categorized as nanoplankton with small cell sizes.
Pyrrophyta (Fire Algae)
- Unicellular organisms prevalent in oceans and some fresh waters, utilizing flagella for movement.
- Classified into dinoflagellates and cryptomonads; dinoflagellates are known for causing red tides and bioluminescence.
- Certain species produce neurotoxins that can disrupt muscle function, posing risks to other organisms.
Chlorophyta
- Predominantly found in freshwater, with some marine species, characterized by cellulose-based cell walls.
- Contain chloroplasts, enabling photosynthesis, with a mix of unicellular and multicellular forms.
- Multicellular species often form colonies and reproduce via non-motile aplanospores or motile zoospores.
Rhodophyta
- Red algae typically thrive in tropical marine environments and lack flagella and centrioles.
- Found on solid surfaces like reefs; cell walls made of cellulose and carbohydrates.
- Reproduce asexually via monospores and undergo sexual reproduction with alternation of generations.
Phaeophyta
- Brown algae encompass large varieties of seaweed and kelp in marine habitats, characterized by differentiated tissues.
- Structures include anchoring organs, buoyancy pockets, and photosynthetic organs, with a life cycle featuring alternation of generations.
- Examples include sargassum weed, rockweed, and giant kelp, reaching lengths up to 100 meters.
Xanthophyta
- Contains 450 to 650 species, making it the least abundant group of algae, primarily unicellular.
- Characterized by cellulose and silica cell walls and one or two flagella for movement.
- Chloroplasts lack certain pigments, resulting in a lighter color; generally form small cell colonies and prefer freshwater habitats.
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Description
Test your knowledge on the fascinating classifications and characteristics of Euglenophyta, Chrysophyta, and Pyrrophyta. This quiz covers their unique features, ecological roles, and classification debates. Dive deep into the world of these diverse protists!
