What is the Difference Between Algae and Moss

The main difference between algae and moss is that algae are a diverse group of lower plants belonging to the kingdom Protista, whereas moss is a small, flowerless plant belonging to the division Bryophyta under the kingdom of Plantae. Furthermore, algae are thallophytes, while moss develops root-like, shoot-like, and leaf-like structures. 

Algae and moss are two types of primitive plants, which are non-vascular, non-flowering, and non-seed producing. Generally, they grow in aquatic or damp environments. 

Key Areas Covered 

1. What is Algae
     – Definition, Features, Classification
2. What is Moss
     – Definition, Features, Classification
3. What are the Similarities Between Algae and Moss
     – Outline of Common Features
4. What is the Difference Between Algae and Moss
     – Comparison of Key Differences

Key Terms 

Algae, Brown Algae, Bryophytes, Gametophyte, Green Algae, Moss, Red Algae

What is Algae 

Algae are plant-like, unicellular or multicellular organisms with a thallic plant body. They belong to the kingdom Protista. Furthermore, they only live in aquatic habitats: in both freshwater and marine water. Besides, they contain chlorophyll and undergo photosynthesis. Therefore, most algae are autotrophs. However, some of the algae can be heterotrophs or mixotrophs. Besides, algae serve as primary producers of most of the aquatic food chains. They also produce 70% of the atmospheric oxygen.

Figure 1: Green Algae

Furthermore, the three divisions of algae are Chlorophyta (green algae), Rhodophyta (red algae), and Phaeophyta (brown algae). They contain different combinations of photosynthetic pigments. Generally, green algae are a diverse group of algae, and they contain chlorophyll, beta-carotene, and xanthophyll. Phycoerythrin is the main type of photosynthetic pigment in red algae. On the other hand, chlorophyll c and fucoxanthin are the two main photosynthetic pigments in brown algae. 

What is Moss 

Moss is a primitive plant classified under the division Bryophyta. Generally, they are non-seed producing, non-flowering, and non-vascular plants. Also, they undergo an alteration of generations, and their dominant stage of the life cycle is the gametophyte. Further, their sporophyte depends on the gametophyte and produces spores. Besides, they also contain chlorophyll and undergo photosynthesis.

Figure 2: Mosses

Basically, mosses are terrestrial plants that inhabit shady and moist places. Moreover, multicellular mosses grow up to several meters. In mosses, rhizoids are the root-like structures that anchor the plant to the surface. Normally, the leaf-like structures of mosses are single-cell thick. Besides, the other two divisions of the clade Embryophyta are liverworts (Marchantiophyta) and hornworts (Anthocerotophyta). Here, the leaf-like structures of liverworts are flat and liver-like. In contrast, hornworts contain sporophytes, which are elongated horn-like structures. 

Similarities Between Algae and Moss 

• Algae and moss are the two most primitive types of plants. 
• Both are eukaryotes. 
• They mostly live in aquatic or damp environments. 
• Also, both are non-vascular plants. 
• Their plant body is not differentiated into leaf, stem, and root. 
• Moreover, they are non-flowering plants and do not produce seeds. 
• But, both contain chlorophyll; hence, they undergo photosynthesis.  
• Therefore, they are autotrophs. 
• Besides, their major photosynthetic pigments are chlorophyll a, b, and carotenes. 
• On the other hand, they contain a type of plastids called pyrenoids. 
• Both undergo vegetative reproduction through fragmentation and adventitious tubers.  
• Their dominant stage of the life cycle is the gametophyte. 
• Furthermore, they produce flagellated sperms, which are mobile. 
• Therefore, their fertilization requires water. 

Difference Between Algae and Moss 

Definition 

Algae refer to a photosynthetic group of organisms that possess pigments such as chlorophyll but, lack true roots, stems, and leaves, while moss refers to a small, flowerless, green plants, which lack true roots, growing in low carpets or rounded cushions in damp habitats. Thus, this is the main difference between algae and moss.

Taxonomy 

Algae belong to the kingdom Protista while mosses belong to the division Bryophyta under kingdom Plantae. 

Habitat 

Also, another difference between algae and moss is that algae grow in aquatic habitats while moss grows in moist, shady places. 

Unicellular/Multicellular 

There are both unicellular and multicellular algae, but all mosses are multicellular. 

Plant Body 

Further, their plant body structure is another difference between algae and moss. Algae can be filamentous, thalloid or leafy while mosses contain leaf-like, root-like, and stem-like structures. 

Division of Labor 

The plant body of algae exhibits no division of labor, while the plant body of mosses internally divides into photosynthetic and storage zones. 

Number of Chloroplasts 

Each cell of algae contains one or few chloroplasts, while many chloroplasts present per each cell of moss. 

Pores or Stomata 

Moreover, algae lack pores or stomata, while mosses contain pores or stomata for gas exchange. 

Rhizoids 

Importantly, algae lack rhizoids, while mosses contain two types of rhizoids: smooth-walled and tuberculated. 

Growth and Reproduction 

Each and every cell of algae can undergo reproduction, while only apical cells of mosses can undergo reproduction.  

Asexual Reproduction 

Zoospores, aplanospores, and hypnospores are the asexual spores of algae, while mosses produce spores in their sporophyte. 

Sexual Reproduction 

Sexual reproduction of algae occurs through the production of isogamous, anisogamous or oogamous gametes, while sexual reproduction in mosses occurs only through oogamous gametes. Hence, this is also a difference between algae and moss.

Sterile Jacket 

The sterile jacket does not occur covering sex organs of algae, while sterile jacket occurs surrounding sex organs of mosses. 

Female Sex Organ 

Oogonium is the female sex organ of algae, while the archegonium is the female sex organ in mosses. 

Zygote 

The zygote of algae liberates from the mother plant, while the zygote of mosses remains in the archegonium. 

Embryo 

No embryo formation occurs in algae, while the embryo forms from the zygote of mosses. 

Sporophyte 

The sporophyte of algae is independent upon the gametophyte, while the sporophyte of mosses depends on the gametophyte. 

Sporophyte Differentiation 

Sporophyte does not differentiate into distinct structures in algae, while the sporophyte of mosses differentiates into the root, seta, and capsule. 

Mitospores 

Mitospores are present in algae, while mitospores are absent in mosses. 

Alteration of Generation 

Alteration of generation in algae is isomorphic, while alteration of generation in mosses is heteromorphic. 

Role in Ecosystems 

Algae serve as the primary producers in aquatic food chains while releasing a high proportion of breathable oxygen to the atmosphere. Meanwhile, moss produces important buffer systems for other plants. 

Types 

The three main types of algae are green algae, red algae, and brown algae, while the three main divisions of division Embryophyta are mosses, hornworts, and liverworts. 

Conclusion 

Algae are a type of lower plants that belong to the kingdom Protista. They can be either unicellular or multicellular. Their plant body is a thallus. Generally, they live in aquatic habitats. The three types of algae are green algae, red algae, and brown algae. On the other hand, moss is a type of primitive plant that belongs to the division Bryophyta. Generally, mosses are multicellular, and their plant body differentiates into root-like, stem-like, and leaf-like structures. Furthermore, the other two groups of division Bryophyta are liverworts and hornworts. Therefore, the main difference between algae and moss is the structure of the plant body. 

References:

1. Vidyasagar, Aparna. “What Are Algae?” LiveScience, Purch, 4 June 2016, Available Here.
2. Posey, Lauren. “What Is Moss? – Definition, Types & Characteristics.” Study.com, Study.com, Available Here.

Image Courtesy:

1. “Stigeoclonium sp zugespitzte seitenzweige” By Kristian Peters Own work (CC BY-SA 3.0) via Commons Wikimedia   
2. “Moss Gametophytes Sporophytes” By Bob Blaylock – Own work (CC BY-SA 4.0) via Commons Wikimedia