Difference Between Algae and Plants

Algae vs Plants

Although the meanings and sounds of the words plant and algae are different, some people still find difficult to differentiate those two apart. Therefore, some simple but interesting information would be helpful to differentiate plants and algae according to the basic characteristics. However, both plants and algae are ecologically similar in the ecosystem, and they independently produce their own food being autotrophs. Despite the similarities, the prevailing differences between plants and algae are discussed in this article.


Algae are eukaryotic autotrophs with either unicellular or multicellular forms. Algae are simple life forms that play a great role in the energy circulation throughout the world. Algae being simple, there are no specialised organs and cells. In fact, the tissues found in algae are not considered as true plant tissues. The forms of algae could be of mainly three types known as Unicellular, Thallus, or Filamentous. They are mostly found in the aquatic ecosystems, and the number of terrestrial algal species is low. They could be either sessile or free-floating in the aquatic environment. When they are sessile, the whole body is connected to the substrate through the structure called Hold Fast or Rhizoid. Algae do not absorb nutrients from the substrate through the hold fast, but they are autotrophs. Collectively, they produce the largest amount of food through photosynthesis. Their photosynthetic pigments are chlorophyll, carotenoid, and phycobilin. Algae are a tremendously diverse group with innumerable number of species. One good example to imagine their diversity is that there are over 320,500 specimens of different species collected in the US National Herbarium. Their great diversity is justifiable with their long, long history that goes about a couple of billion years from toady.


Plants could be simply defined taxonomically by describing as members of the Kingdom: Plantae. Plants are highly adapted to capture sunlight and absorb nutrients from the ground. The tissues in the plants are true plant tissues with a high degree of specialization to certain functions, and that implies plants are complex organisms. The majority of the plants are found in the terrestrial ecosystem using those specializations. Except for very few species, plants are sessile with a highly developed system of roots to attach to the substrate. The roots of plants are not only attached to the ground but also absorb nutrients and water from the soil. Those absorbed contents travel through a system of channels called xylem and phloem to perform their functions. Photosynthesis is one of the major functions of plants, which produces the food for animals. Chlorophyll and carotenoid are the most common photosynthetic pigments used to capture sunlight in plants. However, the body form of plants contains mainly three major structures known as Leaves, Roots, and Trunk. Additionally, plants could never be unicellular but always eukaryotic multicellular. There are about 315,000 species of plants extant on the Earth, which is a great diversity; most of those (about 290,000 species) are flowering plants. The earliest plant fossil has been studied, and age is found to be more than 450 million years.


What is the difference between Algae and Plant?

• Algae could be unicellular or multicellular while plants are always multicellular.

• Plants have true tissues but not in algae.

• Algae could be unicellular, filamentous, or thallus in their structure whereas plants always have roots connected to a trunk that extends leaves.

• Plants are mostly sessile while algae are mostly free-floating.

• Plants have roots to attach to the substrate and to absorb water and nutrients, whereas algae have root-like hold fast or rhizoid only to attach but not to absorb anything.

• Plants are mostly terrestrial while algae are mostly aquatic.

• Chlorophyll and carotenoid are the photosynthetic pigments present in plants while algae have phycobilin in addition.