Moss vs Algae
All organisms are grouped in to five kingdoms. Those are Monera, Protoctista, Fungi, Plantae and Animalia. The division is made based on 3 criteria. Those are cellular organization, arrangement of cells, and type of nutrition. Cellular organization is whether they are eukaryotic or prokaryotic. Cell arrangement is whether they are unicellular, multicellular, with or without true tissue differentiation etc. Type of nutrition is whether they are autotrophic or heterotrophic. Kingdom Protoctista includes algae, protozoans, oomycota and slime moulds. Kingdom plantae includes bryophytes, pterophytes, lycophytes, cycadophytes and anthophytes. In other words, algae come under kingdom Protoctista and mosses come under kingdom plantae.
There are four phyla in kingdom Protoctista that includes different types of algae. Those are phylum Chlorophyta that includes green algae, phylum Phaeophyta that includes brown algae, phylum Rhodophyta that includes red algae, and phylum Bacillariophyta, which includes diatoms. Algae are a large group of organisms (protoctistans) that are of high biological importance. They are often photosynthetic eukaryotes living in water. Algae can be found in both marine and fresh water. Body of algae lacks stems, leaves or roots. Therefore, their body is called a thallus. Algae are grouped into different phyla based on the type of their photosynthetic pigments. All those phyla have some general characteristics in common. Almost all are well adapted to life in water. They show a large diversity among the group members in terms of size and form. They include unicellular, filamentous, colonial, and thalloid forms.
Phylum bryophyta includes the simplest land plants. It is assumed that they have evolved from green algae. There are two main classes in the phylum bryophyta. Those are class Hepaticae that includes liverworts and class Musci, which includes mosses. These groups are not well adapted to life on land. They are confined to moist, shady places. These plants are only few centimeters tall. Alternation of generations is present where the gametophyte is dominant. In class Musci or mosses, the gametophyte is differentiated into ‘stem’ and ‘leaves’. Leaves are arranged spirally around the stem in three rows. Gametophyte is anchored to the ground by rhizoids. These rhizoids are multicellular. The sporophyte grows attached to the female gametophyte. The sporophyte partially depends on the female gametophyte. The spore dispersal is by an elaborate mechanism. It depends on dry conditions, and there are no elaters.
What is the difference between Algae and Mosses?
• Algae belong to phylum Chlorophyta, Phaeophyta, Rhodophyta or Bacillariophyta of kingdom Protoctista, whereas mosses belong to class Musci of phylum Bryophyta of kingdom Plantae.
• Although algae do not have true body differentiation in to roots, stems, and leaves, mosses have somewhat differentiation in stems and leaves.
• Mosses are anchored to the ground by rhizoids and algae are anchored to the substratum by a structure known as the holdfast.
• Alternation of generations is present in mosses, and there is no alternation of generations in algae.
• Most of the algae live in marine or fresh water, whereas the mosses live in moist, shady terrestrial habitats.
• There can be unicellular algae but never unicellular mosses.