Difference Between Algae and Plants

Some algae like Euglenoids are unicellular, while others like Oedogonium are multicellular organisms. Alternatively, there are no unicellular plants.

This seminal difference is implicated in several other notable divergences between the two.

Algae vs Plants

The main difference between algae and plants is that while algae can be either unicellular or multicellular organisms, plants are always multicellular organisms.

Algae may be found as organisms with only a single cell or they may be multicellular beings living in colonies.

Hence, sometimes they have to be examined under the microscope to be visible to the human eye. Plants have several diverse body parts like roots, shoots, flowers, etc. and thus cannot be unicellular.

Comparison Table Between Algae and Plants

What are Algae?

Algae are one of the simplest forms of life visible on the earth. As either single cellular or multicellular autotrophic organisms, algae use sunlight and chlorophyll to produce their own food.

Their bodies are devoid of any structural differentiations as well as vascular bundles.

Although earlier they were classed as a sub-category of the plant kingdom, Algae now belong to the Protista Kingdom. Usually, algae colonies can be found underwater.

Some forms of algae also tend to grow in snow and on the fur coats of certain animals like the sloth. Current research suggests that there are about 320,500 diverse species of algae around the world.

Some Algae have a high degree of mobility. Algae colonies found underwater may freely float in the water. Some may have flagellums to help enhance their mobility.

What are Plants?

Plants are multicellular autotrophic organisms that use air, sunlight, and water to produce food, oxygen, and energy. They belong to the Kingdom Plantae and include several sub-categorizations within their broader classification.  

Most plants are highly vascular organisms. They have complex root and shoot systems consisting of connective tissues that help transport food and water through the body.

These xylem and phloem bundles are essential for the transportation of minerals as well as water.

The body of a plant has several parts like the shoot, branches, leaves, roots, etc. Each part has a specific function to perform. Most plants are found on the surface of the earth, tethered to the soil.

Although, one can also find aquatic plants growing on the seafloor. However, in both cases, the mobility of a plant is extremely limited.

Main Differences Between Algae and Plants

1. The main difference between algae and plants is that they are different in their cell compositions. Algae can be found as unicellular or multicellular organisms, while plants cannot be unicellular. They are always multicellular organisms.
2. The second important difference between the two organisms is that unlike algae, plants have vascular anatomies. Vascular structures like veins, connective tissues, the xylem and phloem systems, etc. are important parts of a plant’s body. Such complex vascularization is absent from the anatomy of algae.
3. Plants and algae belong to different biological categorizations. Plants are classified under the ‘Kingdom Plantae’, while algae are categorized under the ‘Kingdom Protista’.
4. The degree of mobility available to each organism is also different. While plants are generally tethered to the ground and are therefore immobile, algae are free-floating. They have a higher degree of mobility.
5. The differentiation between the root and shoot system that is commonly found in plants is not found in algae.
6. Plants thrive by the absorption of water and mineral nutrients from the soil. Algae do not absorb such nutrients from any surface they may be attached to.  
7. The two organisms also differ in terms of their chemical compositions. While plants have the pigments chlorophyll and carotenoid in them, algae have these pigments along with the phycobilin pigment.
8. Algae are mostly found underwater or floating on the surface of water bodies. Although they are mostly aquatic, sometimes they can be found on land and snow. While plants are terrestrial organisms, found tethered to the top-soil. Sometimes they can be found underwater as well.
9. The reproductive systems of plants and algae are also different from each other. Plants have a complex reproductive system, while algae use sporadic reproduction as a means of propagating their species. They can also self-replicate.

Conclusion

People often tend to get confused between algae and plants. Both species are autotrophs that use sunlight to self-produce food and energy.

Although at certain instances they may appear to be overwhelmingly similar, there are some potent and insurmountable differences between the two.

Algae are organisms belonging to the Protista Kingdom. They may be unicellular or multicellular organisms occurring in colonies without a vascular system.

While plants are members of the Plantae Kingdom and have complex vascular bundles that transport water and food throughout the system.

Moreover, algae are generally found underwater. They tend to float freely in the aquatic waters. Some have flagellums that help expand their mobility.

Conversely, plants are terrestrial organisms that remain tethered to the soil. They thrive on land. There may be aquatic plants, but their numbers are fewer than the terrestrial ones.

These differences between the two species of organisms must be cognized to effectively understand each and refrain from making the common mistake of thinking both categories are synonymous with each other.

References

1. https://www.nature.com/articles/s41477-018-0211-0
2. https://www.nature.com/articles/nrm3064