The key difference between Chlorophyceae Phaeophyceae and Rhodophyceae is that Chlorophyceae is a class of green algae while Phaeophyceae is a class of brown algae and Rhodophyceae is a class of red algae.
Algae are a photosynthetic eukaryotic aquatic group of organisms. They are found in fresh and seawater. They are plant-like organisms that belong to Kingdom Protista. Many members are unicellular while some are multicellular. Moreover, some algae are microscopic, while some are macroscopic. Though algae are usually green, there are different coloured algae as well. Based on pigmentation and other characteristics such as types of flagella, reserve food materials, thallus structure and reproduction, etc. algae are classified into several classes. Chlorophyceae, Phaeophyceae and Rhodophyceae are three popular classes of algae.
CONTENTS
1. Overview and Key Difference
2. What is Chlorophyceae
3. What is Phaeophyceae
4. What is Rhodophyceae
5. Similarities Between Chlorophyceae Phaeophyceae and Rhodophyceae
6. Side by Side Comparison – Chlorophyceae vs Phaeophyceae vs Rhodophyceae in Tabular Form
7. Summary
What is Chlorophyceae?
Chlorophyceae is a class of green algae. Most members of this class are aquatic (freshwater or marine water). They are photosynthetic plant-like organisms. They contain chlorophyll a and b. They also contain beta carotene. The shape of chloroplasts varies among green algae species. Chlamydomonas has a cup-shaped big chloroplast while Spirogyra has a spiral-shaped chloroplast.
Figure 01: Green Alga
Moreover, some members of Chlorophyceae have stellate, discoid, reticulate, plate-like or girdle-shaped chloroplasts. Some green algae are unicellular while others are colonial, filamentous or multicellular. Their cell wall contains cellulose. Furthermore, they contain storage bodies called pyrenoids. They store starch. Green algae species possess flagella. Hence, they are motile. Chlorella, Chlamydomonas, Volvox, Spirogyra, Ulothrix, Chara and Ulva are several examples of green algae.
What is Phaeophyceae?
Phaeophyceae is a class of brown algae which are multicellular. Majority of brown algae are marine organisms. They can be filamentous, frond-like or giant kelps. The thallus of brown algae has a leaf-like photosynthetic part, a stalk-like structure and a holdfast.
Figure 02: Brown Alga
Brown algae have chlorophyll a, c, carotenoids and xanthophylls. Moreover, they have fucoxanthin; a golden brown pigment which gives their characteristic greenish-brown colour. The storage foods are mannitol and laminarin fat. Brown algae have two unequal flagella. Sargassum, Laminaria, Fucus and Dictyota are several examples of brown algae. Brown algae are important as a food source and as a habitat.
What is Rhodophyceae?
Rhodophyceae is a class of red algae. They contain a water-soluble red colour pigment called phycoerythrin, which gives them a characteristic red colour. They also contain phycocyanin, chlorophyll a and d. Red algae are mostly marine organisms. They are multicellular thalli. There are unicellular forms as well. The main storage food of red algae is Floridian starch.
Figure 03: Red Algae
Their cell wall contains cellulose. They do not contain flagella. Red algae contribute to coral reefs. Moreover, they are important as a source of nutritional, functional food ingredients and pharmaceutical substances. Ceramium, Polysiphonia, Gelidium, Cryptonemia and Gigartina are several species of red algae.
What are the Similarities Between Chlorophyceae Phaeophyceae and Rhodophyceae?
- Chlorophyceae, Phaeophyceae and Rhodophyceae are three groups of algae.
- They belong to kingdom Protista.
- Both are photosynthetic eukaryotic organisms.
- They are aquatic organisms (found in freshwater, brackish water and saltwater).
- Moreover, they have cellulose in their cell walls.
- They also have chlorophyll a.
- They do not true stems, shoots and leaves.
- Furthermore, they do not have vascular tissues.
- Algae are economically important as a source of crude oil and as sources of food and a number of pharmaceutical and industrial products.
- Moreover, they are ecologically important since most of them produce oxygen.
What is the Difference Between Chlorophyceae Phaeophyceae and Rhodophyceae?
Chlorophyceae is a class of green algae while Phaeophyceae is a class of brown algae and Rhodophyceae is a class of red algae. Thus, this is the key difference between Chlorophyceae Phaeophyceae and Rhodophyceae. Chlorophyceae members are primarily freshwater, while Phaeophyceae members are almost all marine and Rhodophyceae are predominantly marine.
The below infographic lists more differences between Chlorophyceae Phaeophyceae and Rhodophyceae in tabular form.
Summary – Chlorophyceae vs Phaeophyceae vs Rhodophyceae
Chlorophyceae is a class of green algae primarily found in freshwater. Phaeophyceae is a class of brown algae which are almost all marine algae. Rhodophyceae is a class of red algae which are predominantly marine algae. Chlorophyll a and b provide the characteristic green colour to green algae while phycoerythrin and phycocyanin provide characteristic red colour to red algae and fucoxanthin gives the characteristic golden brown colour to brown algae. All three types of algae are food sources and economically important. Thus, this summarizes the difference between Chlorophyceae Phaeophyceae and Rhodophyceae.
Reference:
1. “Classification of Algae.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., Available here.
2. “Red Algae.” Wikipedia, Wikimedia Foundation, 1 Jan. 2021, Available here.
Image Courtesy:
1. “Pediastrum” By Luis Fernández García – Luis Fernández García (CC BY-SA 2.1 es) via Commons Wikimedia
2. “Kelp-forest-Monterey” By Stef Maruch – kelp-forest.jpg (CC BY-SA 2.0) via Commons Wikimedia
3. “Chondrus crispus – Köhler–s Medizinal-Pflanzen-034” By Franz Eugen Köhler, Köhler's Medizinal-Pflanzen – List of Koehler Images (Public Domain) via Commons Wikimedia