What Organisms Are Algae?

Algae, those brightly colored blobs that swim around in the ocean or entrench themselves in wet soil, are subject to a lot of debate and scrutiny among scientists. Many people disagree about what constitutes algae and how the term should actually be defined. Most scientists agree on certain organisms that are algae, but the debate surrounds other organisms that may be algae or may be other eukaryotic organisms.

  1. Classification

    • Traditionally, algae was classified as cyanobacteria, although recently scientists consider it to be a cyanelle organism. Within the cyanelle kingdom, algae are chloroplasts, because they derive energy directly from the sun. Of the various types of chloroplasts, algae are considered to be in one of these groups: euglenophytes, chlorophytes, charophytes, embryophytes or chlorarachniophytes. Although these are the generally accepted categorizations of algae, algae's unique composition and behavior makes it very hard to classify, which is why scientists are constantly changing its classification.

    Characteristics

    • The characteristics of algae lend clues as to why it they are so difficult to define. Algae derive energy from the sun, directly, through photosynthesis. Whereas this would make algae similar to other chloroplasts and plants, algae move around in fluid motions, as an animal would. This leads many to find algae as an animalistic organism, instead of a plant. Making matters even more convoluted, algae are not only found in water, but can be found in soil and ice.

    Types

    • There are many types of algae. Colonial algae are algae that are very small and consist of a few cells, and capsoid algae are non-moving cells that are embedded in other plants. Another type of algae, coccoid, have cell walls and resemble plants. Filamentous and parenchymatous algae are larger forms of algae that branch out and form large structures. Parenchymatous algae even have specialized tissue for performing different tasks, which is a trait of more highly evolved organisms.

    Role in Plant Evolution

    • Algae played a large role in the evolution of plants and continue to do so today. Cyanobacteria, a group of prokaryotes that played large role in plant evolution, are considered to be algae and represent some of the earliest fossil findings. Stemming from these primitive forms of algae, other forms of diverse plant life began to arise, which eventually yielded eukaryotic cells, or multi-celled organisms. Algae, in this process, were predisposed to create genetically diverse DNA, which is why algae formed the building blocks of the diversity of plant life that exists today.